http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–8 ! 2014 Informa UK Ltd. DOI: 10.3109/14767058.2014.954537
ORIGINAL ARTICLE
Maternal and fetal signs and symptoms associated with uterine rupture in women with prior cesarean delivery
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Joseph G. Ouzounian, Johanna Quist-Nelson, David A. Miller, and Lisa M. Korst Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, LAC + USC Medical Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA Abstract
Keywords
Objective: To describe the association between maternal and fetal physical signs and symptoms (signs/symptoms) and childbirth outcomes in women with prior cesarean delivery (CD). Methods: Cases of uterine rupture at a single institution were reviewed to examine risk factors for experiencing signs/symptoms and poor childbirth outcomes. Results: Among 21 014 deliveries, 3252 (15.5%) had prior CD, and 75 (2.3%) had uterine rupture. Of these, 66 (88.0%) labored. Among those who labored, 51 (77.3%) demonstrated signs/ symptoms prior to delivery. Signs/symptoms included vaginal bleeding, abdominal pain, fetal bradycardia and decreased fetal heart rate (FHR) variability. Laboring patients with signs/ symptoms were seven times more likely than those without them to have poor maternal/ neonatal outcome (27/51 [52.9%] versus 2/15 [13.3%], OR ¼ 7.31 [95% CI 1.34–52.43], p ¼ 0.0155). In multivariate analysis, risk factors for poor fetal outcome were cervical ripening (OR 4.99 [95% CI 0.86–28.99, p ¼ 0.0735) and prolonged FHR deceleration/bradycardia (OR 2.78 [95% CI 0.86–9.10], p ¼ 0.0905). Fetal tachycardia was a risk factor for poor maternal outcome (OR 8.10 [95% CI 1.40–46.84], p ¼ 0.0195). Conclusions: Among laboring women with uterine rupture, 77% demonstrated maternal or fetal signs/symptoms before delivery. The presence of at least one sign/symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes.
Childbirth morbidity, fetal tachycardia, silent uterine rupture, uterine rupture classification, uterine rupture documentation
Introduction Uterine rupture is a potentially serious complication of trial of labor after cesarean (TOLAC). It occurs in 778 per 100 000 women who undergo TOLAC at term versus 22 per 100 000 for women who undergo elective repeat cesarean delivery (CD) [1]. In the evidence report supporting the National Institutes of Health (NIH) Consensus Development Conference on Vaginal Birth After Cesarean (VBAC) in 2010 [2], Guise et al. recommend that ‘‘it would be ideal to understand the signs and symptoms of uterine rupture and what, if any, interventions might reduce the likelihood of morbidity and mortality in the event that a uterine rupture does occur’’. There have been few reports regarding maternal and fetal physical signs and symptoms associated with uterine rupture.
Address for correspondence: Joseph G. Ouzounian, MD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, LAC + USC Medical Center, Keck School of Medicine, University of Southern California, 2020 Zonal Ave., IRD Rm 220, Los Angeles, CA 90033, USA. Tel: 323.226.3416. Fax: 323.226.2710. E-mail: [email protected]
History Received 21 May 2014 Revised 21 July 2014 Accepted 11 August 2014 Published online 10 September 2014
The most common sign is a disturbance of the fetal heart rate (FHR), which has a prevalence of 55–87% in good or fair quality studies [2,3]. This is followed by reports of maternal vaginal bleeding, pain and uterine tone disturbances. Prior studies have often included the presence of signs and symptoms in the definition of uterine rupture itself and many studies have referred to asymptomatic uterine rupture of a prior uterine scar as uterine ‘‘dehiscence’’ [2]. In 2010, the NIH Consensus Development Conference on VBAC attempted to standardize the definition by stating that uterine rupture is an ‘‘anatomic separation of uterine muscle, with or without symptoms’’ [1]. The use of such a definition raises the question of whether serious maternal or neonatal consequences occur in patients who undergo uterine rupture without detectable signs or symptoms. What proportion of uterine ruptures, as now defined, are ‘‘silent’’, and are silent cases associated with poor maternal or fetal outcomes? Our objective was to examine a large case series of women who underwent uterine rupture and describe the extent to which their signs and symptoms were associated with serious maternal and fetal outcomes. In contrast to examining risk factors for uterine rupture and attempting to predict who will experience uterine rupture, here we examine risk factors
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for poor outcomes among women who are known to have experienced uterine rupture.
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Methods We conducted a retrospective cohort study of women who delivered liveborn infants at the Los Angeles County + University of Southern California Medical Center from August 1995 to February 2004. The study was approved by the Institutional Review Board for Human Subjects, and complied with all patient protection criteria stipulated therein. To obtain information regarding maternal and neonatal characteristics and outcomes during hospitalization, clinical data were extracted from a perinatal database comprised of records from routine ongoing medical record review that were matched to administrative records containing International Classification of Diseases, Version 9, Clinical Modification (ICD-9-CM) codes. These linkages were made because clinical and administrative data sources are both highly specific and have different levels of sensitivity for capturing a variety of important data items [4–6]. Of the total deliveries during the study period, all patients with a history of a previous CD were identified by clinical data. From this group, all patients identified as having a uterine scar separation were identified by either clinical data or ICD-9-CM code (i.e. 665.0,1 or 674.1). Medical records for these patients were reviewed to identify the final study population, i.e. those patients who had a previous CD and a uterine rupture, defined here to include either complete (entire thickness of the uterine wall including visceral serosa) or incomplete uterine rupture (intact serosa) [2] as the current definition does not distinguish between the two. Maternal medical records were reviewed to ascertain clinical characteristics of these patients and their hospital course. Neonatal complications were tabulated from administrative data [7] and FHR characteristics were reviewed and tabulated from physician and nursing notes. Physical signs or symptoms potentially associated with uterine scar rupture or dehiscence were classified either as FHR abnormalities versus maternal signs and symptoms. Because the study period predated the classification of FHR patterns by the NIH criteria [8], a mutually exclusive descriptive classification of abnormal FHR patterns as noted in the medical record prior to delivery was performed using the following hierarchy: (1) prolonged deceleration or bradycardia; (2) non-reactive FHR; (3) tachycardia with or without decelerations; (4) late decelerations with or without other decelerations; (5) FHR variable decelerations: prolonged and/ or repetitive; and (6) decreased FHR variability only. Maternal signs and symptoms were recorded from the medical record, and included any abnormal pain or vaginal bleeding, loss of fetal station, increased uterine tone, or changes in the abdominal examination. The identification of placental abruption and extrusion of placental or fetal parts was recorded from the operative note, and for purposes of analysis, these conditions were not aggregated with other signs and symptoms because they were unlikely to be definitively diagnosed prior to the laparotomy. The presence of labor was abstracted from the medical record; patients presenting with spontaneous rupture of
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membranes (SROM) without uterine contractions were classified as presenting in labor. All pregnancy complications (e.g. pre-eclampsia, oligohydramnios), obstetrical complications (e.g. chorioamnionitis, arrest of dilatation or descent) and maternal childbirth outcomes (e.g. bladder rupture, hysterectomy, blood transfusion) were recorded as identified in the medical record for the delivery admission, and were not defined by any other set of criteria. Severe Maternal Childbirth Complications included the above examples of maternal childbirth outcomes and any intra- or post-operative surgical complications, such as organ injury or return to the operating room; endometritis and perineal lacerations were not classified as severe. Severe Neonatal Childbirth Complications were defined as neonatal mortality, or a neonatal intensive care unit (NICU) admission for acute care. Respiratory distress syndrome (RDS) was defined by ICD-9-CM criteria (769), and excludes transient tachypnea of the newborn (770.6). The category, ‘‘Any Severe Childbirth Complication’’, included those patients who had either Severe Maternal or Neonatal Childbirth Complications. Patients who did and did not labor were analyzed separately. For the laboring group, univariate analysis examining the relationship between (a) gestational characteristics and the presence of signs or symptoms, and (b) gestational characteristics and signs or symptoms and the presence of Severe Childbirth Complications was performed. Means are expressed ± the standard deviation (SD), with median and range. Analyses of continuous variables were performed with the Kruskal–Wallis testing; analyses of categorical variables were performed using Chi-square testing, with Yates’ correction or Fisher’s exact testing if appropriate. Those gestational characteristics that appeared to be associated with signs or symptoms (p50.20) were examined using multivariable logistic regression models. Similarly, gestational characteristics that appeared to be associated with childbirth complications (any, maternal or fetal) were examined using multivariable logistic regression models. For logistic regression models, odds ratios (OR) and 95% Confidence Intervals (95% CI) are expressed. All analyses were performed using SAS statistical software (Version 9.2, SAS Institute Inc., Cary, NC).
Results Of 21 014 deliveries that occurred during the study period, 3252 (15.5%) were to women with a prior history of CD. A total of 95 records were identified indicating the occurrence of uterine rupture. Medical records were available for 91 (95.8%), and 75 cases of uterine rupture were positively identified, yielding a prevalence of 2.3% (75/3252). False positives (four for ICD-9-CM codes and 10 for the clinical database) appeared largely associated with medical record documentation of ‘‘rule out uterine rupture’’ (data not shown). Even with careful review of the original medical record, documentation was frequently insufficient to classify cases regarding whether the rupture was complete or incomplete. Of the final 75 patients, 66 (88.0%) labored and nine did not. All gestations were singletons. There were no recorded maternal, fetal or neonatal deaths. Tables 1 and 2 describe
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Table 1. Patient characteristics stratified by the presence of labor.
Patient characteristic
Laboring patients (N ¼ 66)
Non-laboring patients (N ¼ 9)
Maternal race/Ethnicity Hispanic Black Asian White
59 (89.4%) 4 (6.1%) 2 (3.0%) 1 (1.5%)
6 2 1 0
Maternal age (years)
31.1 ± 5.4 30.9 (19.0–43.8)
29.9 ± 4.9 28.9 (21.8–39.7)
Gestational age (weeks)
39.3 ± 2.0 39.3 (29.9–42.1)
38.9 ± 1.8 38.9 (36.1–41.3)
Prenatal care
62 (93.9%)
8 (88.9%)
Previous cesarean number 1 2 3 6
N ¼ 65 52 (80.0%) 12 (18.5%) 0 (0%) 1 (1.5%)
2 4 3 0
Previous vaginal birth after cesarean number 0 1 2 3
55 (83.35) 8 (12.1%) 1 (1.5%) 2 (3.0%)
0 (0%)
Uterine scar history Classical Low transverse Undocumented
2 (3.0%) 20 (30.3%) 44 (66.7%)
2 (22.2%) 1 (11.1%) 6 (66.7%)
Non-vertex presentation
3 (4.5%)
1 (9.1%)
Reason for admission
Spontaneous labor (N ¼ 44) Induced labor (N ¼ 22)
Abdominal pain (N ¼ 1) Elective repeat cesarean (not in labor) (N ¼ 8)
(66.7%) (22.2%) (11.1%) (0%)
N¼9 (22.2%) (44.4%) (33.3%) (0%)
Data expressed as n (%), or mean ± SD, median (range).
patient characteristics and reasons for hospital admission and the types of signs or symptoms experienced. Laboring patients Of the 66 laboring patients, 42 (63.6%) underwent CD during the first stage of labor, 15 (22.7%) underwent CD during the second stage of labor, and nine (13.6%) underwent a postpartum laparotomy after having a vaginal delivery. Eight (12.1%) had an open classical or midline scar, 54 (81.8%) had an open low transverse scar, and four (6.1%) did not have the rupture or dehiscence site described. Of those with an open low transverse scar, 12 (22.2%) had a further extension into or rupture of the lower uterine segment, broad ligament or bladder. FHR abnormalities were documented for 48 laboring patients (72.7%), and 16 (33.3%) of these had a prolonged deceleration or bradycardia. Maternal signs or symptoms were present in 11 laboring patients (16.7%); of these, eight (72.7%) were associated with ‘‘crash’’ CD. In total, 51 laboring patients (77.3%) had either maternal or fetal signs or symptoms that may have been associated with uterine rupture. There were no differences in the prevalence of signs or symptoms by maternal age or race group, or history of
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prenatal care. Risk factors for a ‘‘silent’’ rupture included: more than one prior CD (46.2 versus 15.4%, p ¼ 0.0581); no prior VBAC (37.5 versus 0%, p ¼ 0.0569); and no use of oxytocin (41.1 versus 16.3%, p ¼ 0.0477). Patients who were found at laparotomy to have an abruption (25.5%) or extrusion of the cord or fetal parts into the abdomen (23.5%) all demonstrated maternal or fetal signs or symptoms. Using multivariate logistic regression modeling, the only statistically significant predictor of any maternal or fetal signs or symptoms was the presence of more than one prior CD (OR ¼ 0.29 [95% CI 0.06–0.80], p ¼ 0.0218, c-statistic ¼ 0.646). In other words, patients with multiple prior CD were more likely to have a ‘‘silent’’ scar separation (OR ¼ 3.45, [95% CI 1.25–16.7], p ¼ 0.0218). Table 3 describes all complications for mother and newborn. Seven patients (13.7%) had severe maternal complications and, independently, 25 patients (37.9%) had severe neonatal complications. Laboring patients with signs or symptoms were seven times more likely than those without them to have Any Severe Maternal or Neonatal Complication (27/51 [52.9%] versus 2/15 [13.3%], OR ¼ 7.31 [95% CI 1.34–52.43], p ¼ 0.0155). Although documented signs or symptoms varied widely, the presence of at least one sign or symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes. The two patients who had no signs or symptoms but who experienced severe complications had the following histories: (1) a patient with a uterus didelphys and history of a prior classical uterine incision arrived in early labor at 36 gestational weeks and delivered a neonate with sepsis and respiratory distress; and (2) a patient who had an induction of labor because of cholestasis at 36 gestational weeks underwent CD secondary to an arrest of dilatation, was found to have an open low-transverse uterine scar, and delivered a neonate with respiratory distress. The association of patient characteristics and physical signs or symptoms with severe maternal and neonatal outcomes is described in Table 4. Specific patient characteristics and signs or symptoms potentially associated with Any Severe Childbirth Complication included: more than one prior CD (10.3 versus 27.8%, p ¼ 0.1514) (protective), FHR late decelerations (34.5 versus 18.9%, p ¼ 0.1691), and FHR prolonged deceleration or bradycardia (34.5 versus 16.2%, p ¼ 0.1466). Multivariable logistic regression predicting Any Severe Childbirth Complication using these variables yielded a model for FHR late decelerations (OR ¼ 2.60 [95% CI 0.81–8.34], p ¼ 0.1074) and prolonged deceleration (OR ¼ 3.09 [95% CI 0.93–10.22], p ¼ 0.0649), with a c-statistic ¼ 0.655. Testing the same group of variables and including placental abruption in the equation yielded a final model with abruption as the sole variable (OR ¼ 3.7 [95% CI 1.01–13.65], p ¼ 0.0484, c-statistic ¼ 0.601). The only specific patient characteristic associated with a Severe Maternal Childbirth Complication was fetal tachycardia (3/7 [42.9%] versus 5/58 [8.6%]), which was confirmed in a logistic regression model yielding an OR ¼ 8.10 [95% CI 1.40–46.84], p ¼ 0.0195, and c-statistic ¼ 0.672. Those with tachycardia had a mean ± SD estimated blood loss of 1407 ± 821 cc compared to 728 ± 77 cc in those without tachycardia (p ¼ 0.0105). Fetal tachycardia was also associated with abruption (4/8 [50.0%] versus 9/58 [15.5%], p ¼ 0.0421), and
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Table 2. Physical signs and symptoms potentially associated with uterine rupture occurring in laboring patients (N ¼ 66). Patient characteristic
Laboring patients
No (N ¼ 17, 25.8%) Yes (N ¼ 48, 72.7%): mutually exclusive hierarchy Prolonged deceleration or bradycardia (N ¼ 16) Fetal heart rate non-reactive & late decelerations (N ¼ 1) Tachycardia with or without decelerations (N ¼ 7) Late decelerations with & without other decelerations (N ¼ 9) Amnioinfusion for variable decelerations (N ¼ 4) FHR variables: prolonged and/or repetitive (N ¼ 4) Decreased beat-to-beat variability (N ¼ 7) Unknown (N ¼ 1, 1.5%) (Presented with severe vaginal bleeding) Late decelerations 17 (25.8%) Prolonged deceleration 16 (24.2%) Fetal tachycardia 8 (12.1%) Variable decelerations 18 (27.3%) Maternal signs or symptoms (Antepartum) No (N ¼ 55, 83.3%) Yes (N ¼ 11, 16.7%) Abdominal pain (N ¼ 2) Abdominal pain + increased tone (N ¼ 1) Abdominal pain + palpable fetal parts (N ¼ 1) Abdominal shape change, vertex to breech (N ¼ 1) Loss of station (N ¼ 1) Vaginal bleeding (N ¼ 3) Vaginal bleeding and loss of station (N ¼ 1) Vaginal bleeding, abdominal pain, loss station (N ¼ 1) Any signs or symptoms (maternal signs or symptoms No (N ¼ 15, 22.7%) or fetal heart rate disturbance) Yes (N ¼ 51, 77.3%) Fetal heart rate only (N ¼ 39) Fetal heart rate + abdominal shape change (N ¼ 1) Fetal heart rate + abdominal pain (N ¼ 1) Fetal heart rate + abdominal pain + palpable fetal parts (N ¼ 1) Fetal heart rate + abdominal pain + increased uterine tone (N ¼ 2) Fetal heart rate + vaginal bleeding (N ¼ 2) Fetal heart rate + vaginal bleeding + loss of station (N ¼ 1) Abdominal pain (N ¼ 1) Loss of station (N ¼ 1) Vaginal bleeding + loss of station (N ¼ 1) Vaginal bleeding (fetal heart rate unknown) (N ¼ 1) Signs or symptoms present on admission 10 (15.2%)
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Fetal heart rate abnormal during hospitalization
maternal packed red blood cell (PRBC) transfusion (2/8 [25.0%] versus 1/58 [1.7%], p ¼ 0.0367). It was also associated with chorioamnionitis (6/8 [75.0%] versus 11/58 [19.0%], p ¼ 0.0027). Non-laboring patients The characteristics of the nine non-laboring patients were generally unremarkable. Only one patient was symptomatic prior to laparotomy, and she presented with severe abdominal pain. The others presented for scheduled elective repeat cesarean delivery. None of the patients had experienced a prior VBAC. Three asymptomatic patients (33.3%) had severe outcomes: (1) neonate with respiratory distress who was admitted to the NICU; (2) mother who received a PRBC transfusion; and (3) neonate with meconium aspiration and respiratory distress who was admitted to the NICU.
Discussion The purpose of this study was to examine a population-based cohort of women who underwent uterine rupture as defined by the NIH Consensus Conference in 2010, describe their
physical signs and symptoms, and the extent to which these symptoms were associated with serious maternal and fetal outcomes. The descriptive results of this study show that the majority (88%) of uterine ruptures occurred in the presence of labor and 77% were accompanied by maternal or fetal signs or symptoms (i.e. 23% were ‘‘silent’’). The sole patient characteristic significantly associated with silent rupture in laboring women was more than one prior CD. This is a clinically compelling finding that should be factored into clinical management of such patients. Among laboring patients, the prevalence of a FHR abnormality was 73%, which is consistent with the prevalence of FHR abnormalities reported in the literature (55–87%) [3]. While the types of FHR abnormalities varied, one-third of these cases (and 24% of all laboring women with uterine rupture) demonstrated a prolonged deceleration or bradycardia. Maternal signs or symptoms in laboring women were more unusual (17% of cases), and were predominantly associated with ‘‘crash’’ CD. Vaginal bleeding and abdominal pain were equally prevalent (7.6%), followed by a loss of station (4.6%). The occurrence of physical signs or symptoms appeared to be associated with
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Table 3. Patient complications associated with clinical signs or symptoms in laboring patients (N ¼ 66).
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Patients with signs or symptoms (N ¼ 51)
Patients without signs or symptoms (N ¼ 15)
MATERNAL *Bladder rupture (N ¼ 2) Chorioamnionitis (N ¼ 12) Chorioamnionitis + fourth degree perinatal laceration (N ¼ 1) *Chorioamnionitis + intestinal obstruction (N ¼ 1) *Cesarean hysterectomy (N ¼ 1) Cystoscopy (N ¼ 1) *Transfusion of packed red blood cells + chorioamnionitis (N ¼ 2) *Transfusion of packed red blood cells + fresh frozen plasma (N ¼ 1) None (N ¼ 30)
MATERNAL Chorioamnionitis (N ¼ 1) Uterine inversion (N ¼ 1) None (N ¼ 13)
NEONATAL *CNS symptoms + intubation (N ¼ 1) *CNS symptoms + perinatal infection (N ¼ 3) *CNS symptoms + perinatal infection + meconium aspiration (N ¼ 1) *CNS symptoms + respiratory distress syndrome + perinatal infection + ventilation + hypoglycemia (N ¼ 1) Infant of a diabetic mother (N ¼ 1) Infant of a diabetic mother + metabolic disturbance (N ¼ 1) *Meconium aspiration syndrome + respiratory distress syndrome (N ¼ 1) *Meconium (N ¼ 1) Meconium (N ¼ 1) Neonatal intensive care unit for weight criteria (N ¼ 1) *Perinatal infection (N ¼ 3) *Perinatal infection + intubation (N ¼ 1) Perinatal infection + intubation (N ¼ 1) *Perinatal infection + gastrointestinal hemorrhage (N ¼ 1) *Perinatal infection + meconium (N ¼ 1) *Respiratory distress syndrome (N ¼ 1) *Respiratory distress syndrome + perinatal infection + ventilation + hypoglycemia at 30 weeks’ gestational age (N ¼ 1) *Respiratory distress syndrome + infant of a diabetic mother (N ¼ 1) *Respiratory distress syndrome + perinatal infection (N ¼ 2) Respiratory distress syndrome + phototherapy (N ¼ 1) *Sepsis (N ¼ 1) *Sepsis + hypoglycemia (N ¼ 1) Substance use (N¼2) *Transient tachypnea of the newborn (N ¼ 2) None (N ¼ 20)
NEONATAL Infant of a diabetic mother (N ¼ 1) *Respiratory distress syndrome (N ¼ 1) *Respiratory distress syndrome + sepsis (N ¼ 1) Meconium (N ¼ 2) None (10)
Cases classified as severe are indicated by an asterisk.
a longer mean duration of ruptured membranes and admission-delivery time. Prolonged labor is known to be a risk factor for uterine rupture, and this excess time may also lead to further opportunities for FHR abnormalities to appear [2,9–11]. Of note, nearly all patients had epidural analgesia during labor (94%), but the duration of epidural analgesia was not associated with the appearance of physical signs or symptoms [9,12]. The analytical portion of this study demonstrated that laboring patients with physical signs or symptoms were seven times more likely than those without them to have a poor maternal or neonatal outcome. Although women with multiple prior cesarean deliveries initially appeared less likely to have Any Severe Childbirth Outcome, this relationship did not persist in the multivariable models, where only FHR late decelerations and bradycardia were retained as important risk factors. It is important to emphasize that such physical signs were associated with poor outcomes of patients undergoing uterine rupture and such information does not assist in determining who will undergo uterine rupture. FHR abnormalities, for example, are common findings in many labors that do not result in uterine rupture and the positive predictive value of such information is likely to be low. Furthermore,
severe outcomes were not causally linked to uterine rupture for each individual case, and it may be argued that some outcomes, e.g. respiratory distress or sepsis, did not directly result from uterine rupture. However, neonatal respiratory morbidity can be attributed to hypoxia caused by uterine rupture, and sepsis can contribute to the onset of neonatal encephalopathy [13]. A full developmental history of each neonate would have to be undertaken to determine definitive causation in each case. An important new finding in this study was the association of fetal tachycardia with poor maternal outcomes. This was highly associated with abruption, maternal blood loss and transfusion. Previous studies indicate that fetal tachycardia does not appear to distinguish cases of uterine rupture from non-rupture in women undergoing TOLAC [14]. Although documented physical signs and symptoms varied widely, the presence of at least one sign or symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes. Two cases of silent uterine ruptures during labor were associated with poor neonatal outcomes (including respiratory distress). Furthermore, recent evidence suggests that complete uterine ruptures can be ‘‘masked’’, whereby the rupture site may remain localized either externally
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Table 4. Risk factors for Severe Childbirth Outcomes in laboring women.
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Patient characteristics Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
Percent of Patients with ANY severe outcome who have characteristic (N ¼ 29)
5 (13.5%)
0.7383 0.0107
10 (34.5%) 18/42 (42.9%) 7/15 (46.7%) 4/9 (44.4%)
8 (21.6%)
0.2765 0.9674
8 9 12 5 23 3/29 6 10 10 5 10
(27.6%) (31.0%) (41.4%) (17.2%) (79.3%) (10.3%) (20.7%) (34.5%) (34.5%) (17.2%) (34.5%)
4 4 10 2 26 10/36 5 7 6 3 8
(10.8%) (10.8%) (27.0%) (5.4%) (70.3%) (27.8%) (13.5%) (18.9%) (16.2%) (18.1%) (21.6%)
Percent of Patients WITHOUT severe MATERNAL complication who have characteristic (N ¼ 59)
0.1521 0.0821 0.2942 0.2259 0.5717 0.1514 0.5153 0.1691 0.1466 0.2852 0.2765
p value
2 (28.6%) 0/3 (0%) 5/41 (12.2%) 2/7 (28.6%) 0/15 (0%)
8 (13.6%)
0.2853 0.2012
4 (57.1%) 3/42 (7.1%) 2/15 (13.3%) 2/9 (22.2%)
14 (23.7%)
0.0816 0.3810
3 (42.9%) 3 (42.9%) 2 (28.6%) 0 (0%) 6 (85.7%) 0/7 (0%) 2 (28.6%) 3(42.9%) 2 (28.6%) 3 (42.9%) 2 (28.6%) Percent of Patients with severe FETAL complication who have characteristic (N ¼ 25)
Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
p value
5 (17.2%) 1/3 (33.3%) 20/41 (48.8%) 6/7 (85.7%) 2/15 (13.3%)
Percent of Patients with Severe MATERNAL complication who have characteristic (N ¼ 7) Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
Percent of Patients WITHOUT ANY severe outcome who have characteristic (N ¼ 37)
9 10 20 7 43 13/58 9 14 14 5 16
(15.3%) (16.9%) (33.9%) (11.9%) (72.9%) (22.4%) (15.3%) (23.7%) (23.7%) (8.5%) (27.1%)
Percent of Patients WITHOUT severe FETAL complication who have characteristic (N ¼ 41)
0.1066 0.1314 1.0000 1.0000 0.6670 0.3287 0.3300 0.3618 1.0000 0.0344 1.0000
p value
3 (12.0%) 1/3 (33.3%) 16/41 (39.0%) 6/7 (85.7%) 2/15 (13.3%)
7 (17.1%)
0.7304 0.0135
8 (32.0%) 17/42 (40.5%) 5/15 (33.3%) 3/9 (33.3%)
10 (24.4%)
0.5740 0.3810
6 7 10 5/25 20 3/25 5/25 8 9 4 9
(24.0%) (28.0%) (40.0%) (20.0%) (80.0%) (12.0%) (20.0%) (32.0%) (36.0%) (16.0%) (36.0%)
5 5 12 2 29 10/40 6/41 9 7 4 9
(12.2%) (12.2%) (29.3%) (4.9%) (70.7%) (25.0%) (14.6%) (22.0%) (17.1%) (9.8%) (22.0%)
0.3082 0.1864 0.4258 0.0948 0.5634 0.3390 0.7352 0.3966 0.1372 0.4650 0.2603
Uterine rupture
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DOI: 10.3109/14767058.2014.954537
(e.g. through coverage by the omentum) or internally (e.g. through coverage by fetal parts), and maternal or fetal signs or symptoms may be undetected [15]. Given that nearly a quarter (23%) of laboring patients with uterine rupture had no maternal or fetal signs or symptoms, it is evident that physicians whose patients are undergoing TOLAC are unaware clinically of the impending rupture and are not always ‘‘put on notice’’ [16]. Furthermore, 35% of those who did have signs or symptoms underwent a ‘‘crash’’ CD, implying that there was little opportunity for earlier intervention. Duration of the insult is not the only a factor that may lead to poor outcomes, as the severity of the insult (e.g. whether or not placental abruption occurred) and the fetal status and reserves prior to the insult (e.g. whether intrauterine growth restriction or fetal acidemia were present) also likely contribute to fetal outcomes [17], and are often not measureable in retrospect. Of interest is that in the non-laboring group (N ¼ 9), all three cases with severe outcomes occurred in asymptomatic women. It has long been generally assumed that asymptomatic uterine scar rupture, or what has often been referred to as ‘‘dehiscence’’ is unassociated with maternal or neonatal morbidity, and there are few reports of uterine scar dehiscence rates or outcomes associated with such dehiscence, largely because women undergoing VBAC have not been systematically evaluated. Spong et al. [18], studying approximately 15 000 women from 19 institutions over four years, found the risk of uterine rupture to be 0.74% and the risk of uterine dehiscence to be 0.67% in women with singleton term pregnancies undergoing TOLAC. It is likely that the prevalence of a rupture of previous cesarean scar in our population was higher than expected (2.3%) because of the broad definition of uterine rupture used here. Even so, prior reports have shown varying prevalence depending on the definition and documentation, and have reached up to 3.7% among women undergoing TOLAC with more than one prior CD [1,9]. It is also likely that our higher prevalence of uterine rupture was due to practice patterns during the study period (e.g. more cervical ripening), as well as the high proportions of women with more than one prior uterine scar and with undocumented direction of prior uterine scar. Previously we have shown that labor induction in patients undergoing TOLAC may be a reasonable consideration in some patients [19]. The definition of uterine rupture has remained a subject of controversy over the years. The evidence report prepared for the Agency for Healthcare Research and Quality (AHRQ) regarding VBAC in 2003 documents the discussion held at a ‘‘Uterine Rupture Terminology Conference’’ in 2002, and found many inconsistencies and ambiguities in terminology used for uterine rupture [3]. There was some agreement on the following terms: ‘‘incomplete’’ uterine rupture of a cesarean scar – separation that was not completely through all layers of the uterine wall (e.g. serosa intact), and ‘‘complete’’ uterine rupture of a cesarean scar – entire thickness of the uterine wall including visceral serosa. The subsequent evidence report prepared for the AHRQ in 2010 focused on ‘‘complete’’ uterine rupture in order to compare similar studies [2]. However, the actual guidelines produced by the NIH
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Consensus Conference in 2010 state that ‘‘uterine rupture is defined as an anatomic separation of the uterine muscle with or without symptoms’’, and does not distinguish between complete and incomplete ruptures [1]. In the current study, we combined women with both complete and incomplete ruptures because: (1) medical record documentation often did not distinguish between the two, and (2) both complete and incomplete uterine ruptures were associated with maternal and fetal signs and symptoms and poor childbirth outcomes. Similar findings of under-reporting of uterine rupture secondary to abstraction from plain text (as opposed to ‘‘check boxes’’ or other structured reporting options) have been noted [20]. In summary, this study demonstrated that with the current NIH Consensus Conference definition of uterine rupture, 77% of laboring women undergoing TOLAC who experienced uterine rupture demonstrated maternal or fetal physical signs or symptoms before delivery. Although documented signs and symptoms varied widely, the presence of at least one sign or symptom identified nearly all cases (27/29 [93.1%]) with poor outcomes. Thus, in laboring patients with uterine rupture, lack of signs or symptoms appears to be reassuring. Conversely, 33% of non-laboring women (3/9 cases) had serious neonatal outcomes, and all these women were asymptomatic. Our finding regarding the relationship between fetal tachycardia and maternal symptoms was also clinically compelling and warrants further analysis. Finally, the documentation of uterine rupture and its associated physical signs and symptoms, timing, and outcomes, appears to be inadequate for research studies, and standardization should be a common goal across all health systems.
Declaration of interest The authors report no declarations of interest.
References 1. Cunningham FG, Bangdiwala S, Brown SS, et al. National Institutes of Health Consensus Development Conference Statement: vaginal birth after cesarean: new insights. Obstet Gynecol 2010;115:1279–95. 2. Guise J-M, Eden K, Emeis C, et al. Vaginal birth after cesarean: new insights. Evidence Report/Technology Assessment No. 191 (Prepared by the Oregon Health & Science University Evidencebased Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality. March 2010. Available from: http://www.ahrq.gov/research/findings/evidence-based-reports/ er191-abstract.html [last accessed 22 Dec 2013]. 3. Guise J-M, McDonagh MS, Hashima J, et al. Vaginal Birth After Cesarean (VBAC). Evidence Report/Technology Assessment Number 71 (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-97-0018). AHRQ Publication No. 03-E018. Rockville, MD: Agency for Healthcare Research and Quality. March 2003. Available from: http://www.ncbi.nlm.nih.gov/books/NBK36821/ [last accessed 22 Dec 2013]. 4. Korst LM, Gregory KD, Gornbein JA. Elective primary cesarean delivery: accuracy of administrative data. Paediatr Perinatal Epidemiol 2004;18:112–19. 5. Yasmeen S, Romano PS, Schembri ME, et al. Accuracy of obstetric diagnoses and procedures in hospital discharge data. Am J Obstet Gynecol 2006;194:992–1001. 6. Lain SJ, Hadfield RM, Raynes-Greenow CH, et al. Quality of data in perinatal population health databases: a systematic review. Med Care 2012;50:e7–20.
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7. Gregory KD, Fridman M, Shah S, Korst LM. Global measures of quality- and patient safety-related childbirth outcomes: should we monitor adverse or ideal rates? Am J Obstet Gynecol 2009; 681.e1–e7. 8. American College of Obstetricians and Gynecologists (ACOG). ACOG Practice Bulletin. Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. Number 106, July 2009. 9. American College of Obstetricians and Gynecologists. Practice bulletin: clinical management guidelines for obstetrician-gynecologists. Vaginal birth after previous cesarean delivery. Obstet Gynecol 2010:115:450–63. 10. Leung AS, Farmer RM, Leung EK, et al. Risk factors associated with uterine rupture during trial of labor after cesarean delivery: a case-control study. Am J Obstet Gynecol 1993;168:945–50. 11. Harper LM, Cahill AG, Roehl KA, et al. The pattern of labor preceding uterine rupture. Am J Obstet Gynecol 2012;207:210.e1–6. 12. Cahill AG, Odibo AO, Allsworth JE, Macones GA. Frequent epidural dosing as a marker for impending uterine rupture in patients who attempt a vaginal birth after a previous cesarean: a case-control study. J Reprod Med 2011;56:313–20. 13. American College of Obstetricians and Gynecologists’ Task Force on Neonatal Encephalopathy and Cerebral Palsy, American College
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14. 15. 16. 17. 18. 19. 20.
of Obstetricians and Gynecologists (ACOG) and American Academy of Pediatrics (AAP). Neonatal encephalopathy and cerebral palsy: defining the pathogenesis and pathophysiology. Washington, DC: ACOG; 2003. Ridgeway JJ, Weyrich DL, Benedetti TJ. Fetal heart rate changes associated with uterine rupture. Obstet Gynecol 2004; 103:506–12. Matsubara S. ‘‘Masked uterine rupture’’: key to diagnosis. Arch Gynecol Obstet 2012;286:1075–6. Phelan JP, Korst LM, Martin GI. Causation – fetal brain injury and uterine rupture. Clin Perinatol 2007;34:409–38. Holmgren CM. Uterine rupture associated with VBAC. Clinical Obstet Gynecol 2012;55:978–87. Spong CY, Landon MB, Gilbert S, et al. Risk of uterine rupture and adverse perinatal outcome at term after cesarean delivery. Obstet Gynecol 2007;110:801–7. Ouzounian JG, Miller DA, Hiebert C, et al. Vaginal birth after cesarean section: risk of uterine rupture with labor induction. Am J Perinatol 2011;28:593–6. Al-Zirqi I, Stray-Pedersen B, Forsen L, et al.; The Norwegian Uterine Rupture Group. Validation study of uterine rupture registration in the Medical Birth Registry of Norway. ACTA Obstet Gynecol Scand 2013;92:1086–93.
ORIGINAL ARTICLE
Maternal and fetal signs and symptoms associated with uterine rupture in women with prior cesarean delivery
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Joseph G. Ouzounian, Johanna Quist-Nelson, David A. Miller, and Lisa M. Korst Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, LAC + USC Medical Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA Abstract
Keywords
Objective: To describe the association between maternal and fetal physical signs and symptoms (signs/symptoms) and childbirth outcomes in women with prior cesarean delivery (CD). Methods: Cases of uterine rupture at a single institution were reviewed to examine risk factors for experiencing signs/symptoms and poor childbirth outcomes. Results: Among 21 014 deliveries, 3252 (15.5%) had prior CD, and 75 (2.3%) had uterine rupture. Of these, 66 (88.0%) labored. Among those who labored, 51 (77.3%) demonstrated signs/ symptoms prior to delivery. Signs/symptoms included vaginal bleeding, abdominal pain, fetal bradycardia and decreased fetal heart rate (FHR) variability. Laboring patients with signs/ symptoms were seven times more likely than those without them to have poor maternal/ neonatal outcome (27/51 [52.9%] versus 2/15 [13.3%], OR ¼ 7.31 [95% CI 1.34–52.43], p ¼ 0.0155). In multivariate analysis, risk factors for poor fetal outcome were cervical ripening (OR 4.99 [95% CI 0.86–28.99, p ¼ 0.0735) and prolonged FHR deceleration/bradycardia (OR 2.78 [95% CI 0.86–9.10], p ¼ 0.0905). Fetal tachycardia was a risk factor for poor maternal outcome (OR 8.10 [95% CI 1.40–46.84], p ¼ 0.0195). Conclusions: Among laboring women with uterine rupture, 77% demonstrated maternal or fetal signs/symptoms before delivery. The presence of at least one sign/symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes.
Childbirth morbidity, fetal tachycardia, silent uterine rupture, uterine rupture classification, uterine rupture documentation
Introduction Uterine rupture is a potentially serious complication of trial of labor after cesarean (TOLAC). It occurs in 778 per 100 000 women who undergo TOLAC at term versus 22 per 100 000 for women who undergo elective repeat cesarean delivery (CD) [1]. In the evidence report supporting the National Institutes of Health (NIH) Consensus Development Conference on Vaginal Birth After Cesarean (VBAC) in 2010 [2], Guise et al. recommend that ‘‘it would be ideal to understand the signs and symptoms of uterine rupture and what, if any, interventions might reduce the likelihood of morbidity and mortality in the event that a uterine rupture does occur’’. There have been few reports regarding maternal and fetal physical signs and symptoms associated with uterine rupture.
Address for correspondence: Joseph G. Ouzounian, MD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, LAC + USC Medical Center, Keck School of Medicine, University of Southern California, 2020 Zonal Ave., IRD Rm 220, Los Angeles, CA 90033, USA. Tel: 323.226.3416. Fax: 323.226.2710. E-mail: [email protected]
History Received 21 May 2014 Revised 21 July 2014 Accepted 11 August 2014 Published online 10 September 2014
The most common sign is a disturbance of the fetal heart rate (FHR), which has a prevalence of 55–87% in good or fair quality studies [2,3]. This is followed by reports of maternal vaginal bleeding, pain and uterine tone disturbances. Prior studies have often included the presence of signs and symptoms in the definition of uterine rupture itself and many studies have referred to asymptomatic uterine rupture of a prior uterine scar as uterine ‘‘dehiscence’’ [2]. In 2010, the NIH Consensus Development Conference on VBAC attempted to standardize the definition by stating that uterine rupture is an ‘‘anatomic separation of uterine muscle, with or without symptoms’’ [1]. The use of such a definition raises the question of whether serious maternal or neonatal consequences occur in patients who undergo uterine rupture without detectable signs or symptoms. What proportion of uterine ruptures, as now defined, are ‘‘silent’’, and are silent cases associated with poor maternal or fetal outcomes? Our objective was to examine a large case series of women who underwent uterine rupture and describe the extent to which their signs and symptoms were associated with serious maternal and fetal outcomes. In contrast to examining risk factors for uterine rupture and attempting to predict who will experience uterine rupture, here we examine risk factors
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for poor outcomes among women who are known to have experienced uterine rupture.
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Methods We conducted a retrospective cohort study of women who delivered liveborn infants at the Los Angeles County + University of Southern California Medical Center from August 1995 to February 2004. The study was approved by the Institutional Review Board for Human Subjects, and complied with all patient protection criteria stipulated therein. To obtain information regarding maternal and neonatal characteristics and outcomes during hospitalization, clinical data were extracted from a perinatal database comprised of records from routine ongoing medical record review that were matched to administrative records containing International Classification of Diseases, Version 9, Clinical Modification (ICD-9-CM) codes. These linkages were made because clinical and administrative data sources are both highly specific and have different levels of sensitivity for capturing a variety of important data items [4–6]. Of the total deliveries during the study period, all patients with a history of a previous CD were identified by clinical data. From this group, all patients identified as having a uterine scar separation were identified by either clinical data or ICD-9-CM code (i.e. 665.0,1 or 674.1). Medical records for these patients were reviewed to identify the final study population, i.e. those patients who had a previous CD and a uterine rupture, defined here to include either complete (entire thickness of the uterine wall including visceral serosa) or incomplete uterine rupture (intact serosa) [2] as the current definition does not distinguish between the two. Maternal medical records were reviewed to ascertain clinical characteristics of these patients and their hospital course. Neonatal complications were tabulated from administrative data [7] and FHR characteristics were reviewed and tabulated from physician and nursing notes. Physical signs or symptoms potentially associated with uterine scar rupture or dehiscence were classified either as FHR abnormalities versus maternal signs and symptoms. Because the study period predated the classification of FHR patterns by the NIH criteria [8], a mutually exclusive descriptive classification of abnormal FHR patterns as noted in the medical record prior to delivery was performed using the following hierarchy: (1) prolonged deceleration or bradycardia; (2) non-reactive FHR; (3) tachycardia with or without decelerations; (4) late decelerations with or without other decelerations; (5) FHR variable decelerations: prolonged and/ or repetitive; and (6) decreased FHR variability only. Maternal signs and symptoms were recorded from the medical record, and included any abnormal pain or vaginal bleeding, loss of fetal station, increased uterine tone, or changes in the abdominal examination. The identification of placental abruption and extrusion of placental or fetal parts was recorded from the operative note, and for purposes of analysis, these conditions were not aggregated with other signs and symptoms because they were unlikely to be definitively diagnosed prior to the laparotomy. The presence of labor was abstracted from the medical record; patients presenting with spontaneous rupture of
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membranes (SROM) without uterine contractions were classified as presenting in labor. All pregnancy complications (e.g. pre-eclampsia, oligohydramnios), obstetrical complications (e.g. chorioamnionitis, arrest of dilatation or descent) and maternal childbirth outcomes (e.g. bladder rupture, hysterectomy, blood transfusion) were recorded as identified in the medical record for the delivery admission, and were not defined by any other set of criteria. Severe Maternal Childbirth Complications included the above examples of maternal childbirth outcomes and any intra- or post-operative surgical complications, such as organ injury or return to the operating room; endometritis and perineal lacerations were not classified as severe. Severe Neonatal Childbirth Complications were defined as neonatal mortality, or a neonatal intensive care unit (NICU) admission for acute care. Respiratory distress syndrome (RDS) was defined by ICD-9-CM criteria (769), and excludes transient tachypnea of the newborn (770.6). The category, ‘‘Any Severe Childbirth Complication’’, included those patients who had either Severe Maternal or Neonatal Childbirth Complications. Patients who did and did not labor were analyzed separately. For the laboring group, univariate analysis examining the relationship between (a) gestational characteristics and the presence of signs or symptoms, and (b) gestational characteristics and signs or symptoms and the presence of Severe Childbirth Complications was performed. Means are expressed ± the standard deviation (SD), with median and range. Analyses of continuous variables were performed with the Kruskal–Wallis testing; analyses of categorical variables were performed using Chi-square testing, with Yates’ correction or Fisher’s exact testing if appropriate. Those gestational characteristics that appeared to be associated with signs or symptoms (p50.20) were examined using multivariable logistic regression models. Similarly, gestational characteristics that appeared to be associated with childbirth complications (any, maternal or fetal) were examined using multivariable logistic regression models. For logistic regression models, odds ratios (OR) and 95% Confidence Intervals (95% CI) are expressed. All analyses were performed using SAS statistical software (Version 9.2, SAS Institute Inc., Cary, NC).
Results Of 21 014 deliveries that occurred during the study period, 3252 (15.5%) were to women with a prior history of CD. A total of 95 records were identified indicating the occurrence of uterine rupture. Medical records were available for 91 (95.8%), and 75 cases of uterine rupture were positively identified, yielding a prevalence of 2.3% (75/3252). False positives (four for ICD-9-CM codes and 10 for the clinical database) appeared largely associated with medical record documentation of ‘‘rule out uterine rupture’’ (data not shown). Even with careful review of the original medical record, documentation was frequently insufficient to classify cases regarding whether the rupture was complete or incomplete. Of the final 75 patients, 66 (88.0%) labored and nine did not. All gestations were singletons. There were no recorded maternal, fetal or neonatal deaths. Tables 1 and 2 describe
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Table 1. Patient characteristics stratified by the presence of labor.
Patient characteristic
Laboring patients (N ¼ 66)
Non-laboring patients (N ¼ 9)
Maternal race/Ethnicity Hispanic Black Asian White
59 (89.4%) 4 (6.1%) 2 (3.0%) 1 (1.5%)
6 2 1 0
Maternal age (years)
31.1 ± 5.4 30.9 (19.0–43.8)
29.9 ± 4.9 28.9 (21.8–39.7)
Gestational age (weeks)
39.3 ± 2.0 39.3 (29.9–42.1)
38.9 ± 1.8 38.9 (36.1–41.3)
Prenatal care
62 (93.9%)
8 (88.9%)
Previous cesarean number 1 2 3 6
N ¼ 65 52 (80.0%) 12 (18.5%) 0 (0%) 1 (1.5%)
2 4 3 0
Previous vaginal birth after cesarean number 0 1 2 3
55 (83.35) 8 (12.1%) 1 (1.5%) 2 (3.0%)
0 (0%)
Uterine scar history Classical Low transverse Undocumented
2 (3.0%) 20 (30.3%) 44 (66.7%)
2 (22.2%) 1 (11.1%) 6 (66.7%)
Non-vertex presentation
3 (4.5%)
1 (9.1%)
Reason for admission
Spontaneous labor (N ¼ 44) Induced labor (N ¼ 22)
Abdominal pain (N ¼ 1) Elective repeat cesarean (not in labor) (N ¼ 8)
(66.7%) (22.2%) (11.1%) (0%)
N¼9 (22.2%) (44.4%) (33.3%) (0%)
Data expressed as n (%), or mean ± SD, median (range).
patient characteristics and reasons for hospital admission and the types of signs or symptoms experienced. Laboring patients Of the 66 laboring patients, 42 (63.6%) underwent CD during the first stage of labor, 15 (22.7%) underwent CD during the second stage of labor, and nine (13.6%) underwent a postpartum laparotomy after having a vaginal delivery. Eight (12.1%) had an open classical or midline scar, 54 (81.8%) had an open low transverse scar, and four (6.1%) did not have the rupture or dehiscence site described. Of those with an open low transverse scar, 12 (22.2%) had a further extension into or rupture of the lower uterine segment, broad ligament or bladder. FHR abnormalities were documented for 48 laboring patients (72.7%), and 16 (33.3%) of these had a prolonged deceleration or bradycardia. Maternal signs or symptoms were present in 11 laboring patients (16.7%); of these, eight (72.7%) were associated with ‘‘crash’’ CD. In total, 51 laboring patients (77.3%) had either maternal or fetal signs or symptoms that may have been associated with uterine rupture. There were no differences in the prevalence of signs or symptoms by maternal age or race group, or history of
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prenatal care. Risk factors for a ‘‘silent’’ rupture included: more than one prior CD (46.2 versus 15.4%, p ¼ 0.0581); no prior VBAC (37.5 versus 0%, p ¼ 0.0569); and no use of oxytocin (41.1 versus 16.3%, p ¼ 0.0477). Patients who were found at laparotomy to have an abruption (25.5%) or extrusion of the cord or fetal parts into the abdomen (23.5%) all demonstrated maternal or fetal signs or symptoms. Using multivariate logistic regression modeling, the only statistically significant predictor of any maternal or fetal signs or symptoms was the presence of more than one prior CD (OR ¼ 0.29 [95% CI 0.06–0.80], p ¼ 0.0218, c-statistic ¼ 0.646). In other words, patients with multiple prior CD were more likely to have a ‘‘silent’’ scar separation (OR ¼ 3.45, [95% CI 1.25–16.7], p ¼ 0.0218). Table 3 describes all complications for mother and newborn. Seven patients (13.7%) had severe maternal complications and, independently, 25 patients (37.9%) had severe neonatal complications. Laboring patients with signs or symptoms were seven times more likely than those without them to have Any Severe Maternal or Neonatal Complication (27/51 [52.9%] versus 2/15 [13.3%], OR ¼ 7.31 [95% CI 1.34–52.43], p ¼ 0.0155). Although documented signs or symptoms varied widely, the presence of at least one sign or symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes. The two patients who had no signs or symptoms but who experienced severe complications had the following histories: (1) a patient with a uterus didelphys and history of a prior classical uterine incision arrived in early labor at 36 gestational weeks and delivered a neonate with sepsis and respiratory distress; and (2) a patient who had an induction of labor because of cholestasis at 36 gestational weeks underwent CD secondary to an arrest of dilatation, was found to have an open low-transverse uterine scar, and delivered a neonate with respiratory distress. The association of patient characteristics and physical signs or symptoms with severe maternal and neonatal outcomes is described in Table 4. Specific patient characteristics and signs or symptoms potentially associated with Any Severe Childbirth Complication included: more than one prior CD (10.3 versus 27.8%, p ¼ 0.1514) (protective), FHR late decelerations (34.5 versus 18.9%, p ¼ 0.1691), and FHR prolonged deceleration or bradycardia (34.5 versus 16.2%, p ¼ 0.1466). Multivariable logistic regression predicting Any Severe Childbirth Complication using these variables yielded a model for FHR late decelerations (OR ¼ 2.60 [95% CI 0.81–8.34], p ¼ 0.1074) and prolonged deceleration (OR ¼ 3.09 [95% CI 0.93–10.22], p ¼ 0.0649), with a c-statistic ¼ 0.655. Testing the same group of variables and including placental abruption in the equation yielded a final model with abruption as the sole variable (OR ¼ 3.7 [95% CI 1.01–13.65], p ¼ 0.0484, c-statistic ¼ 0.601). The only specific patient characteristic associated with a Severe Maternal Childbirth Complication was fetal tachycardia (3/7 [42.9%] versus 5/58 [8.6%]), which was confirmed in a logistic regression model yielding an OR ¼ 8.10 [95% CI 1.40–46.84], p ¼ 0.0195, and c-statistic ¼ 0.672. Those with tachycardia had a mean ± SD estimated blood loss of 1407 ± 821 cc compared to 728 ± 77 cc in those without tachycardia (p ¼ 0.0105). Fetal tachycardia was also associated with abruption (4/8 [50.0%] versus 9/58 [15.5%], p ¼ 0.0421), and
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Table 2. Physical signs and symptoms potentially associated with uterine rupture occurring in laboring patients (N ¼ 66). Patient characteristic
Laboring patients
No (N ¼ 17, 25.8%) Yes (N ¼ 48, 72.7%): mutually exclusive hierarchy Prolonged deceleration or bradycardia (N ¼ 16) Fetal heart rate non-reactive & late decelerations (N ¼ 1) Tachycardia with or without decelerations (N ¼ 7) Late decelerations with & without other decelerations (N ¼ 9) Amnioinfusion for variable decelerations (N ¼ 4) FHR variables: prolonged and/or repetitive (N ¼ 4) Decreased beat-to-beat variability (N ¼ 7) Unknown (N ¼ 1, 1.5%) (Presented with severe vaginal bleeding) Late decelerations 17 (25.8%) Prolonged deceleration 16 (24.2%) Fetal tachycardia 8 (12.1%) Variable decelerations 18 (27.3%) Maternal signs or symptoms (Antepartum) No (N ¼ 55, 83.3%) Yes (N ¼ 11, 16.7%) Abdominal pain (N ¼ 2) Abdominal pain + increased tone (N ¼ 1) Abdominal pain + palpable fetal parts (N ¼ 1) Abdominal shape change, vertex to breech (N ¼ 1) Loss of station (N ¼ 1) Vaginal bleeding (N ¼ 3) Vaginal bleeding and loss of station (N ¼ 1) Vaginal bleeding, abdominal pain, loss station (N ¼ 1) Any signs or symptoms (maternal signs or symptoms No (N ¼ 15, 22.7%) or fetal heart rate disturbance) Yes (N ¼ 51, 77.3%) Fetal heart rate only (N ¼ 39) Fetal heart rate + abdominal shape change (N ¼ 1) Fetal heart rate + abdominal pain (N ¼ 1) Fetal heart rate + abdominal pain + palpable fetal parts (N ¼ 1) Fetal heart rate + abdominal pain + increased uterine tone (N ¼ 2) Fetal heart rate + vaginal bleeding (N ¼ 2) Fetal heart rate + vaginal bleeding + loss of station (N ¼ 1) Abdominal pain (N ¼ 1) Loss of station (N ¼ 1) Vaginal bleeding + loss of station (N ¼ 1) Vaginal bleeding (fetal heart rate unknown) (N ¼ 1) Signs or symptoms present on admission 10 (15.2%)
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Fetal heart rate abnormal during hospitalization
maternal packed red blood cell (PRBC) transfusion (2/8 [25.0%] versus 1/58 [1.7%], p ¼ 0.0367). It was also associated with chorioamnionitis (6/8 [75.0%] versus 11/58 [19.0%], p ¼ 0.0027). Non-laboring patients The characteristics of the nine non-laboring patients were generally unremarkable. Only one patient was symptomatic prior to laparotomy, and she presented with severe abdominal pain. The others presented for scheduled elective repeat cesarean delivery. None of the patients had experienced a prior VBAC. Three asymptomatic patients (33.3%) had severe outcomes: (1) neonate with respiratory distress who was admitted to the NICU; (2) mother who received a PRBC transfusion; and (3) neonate with meconium aspiration and respiratory distress who was admitted to the NICU.
Discussion The purpose of this study was to examine a population-based cohort of women who underwent uterine rupture as defined by the NIH Consensus Conference in 2010, describe their
physical signs and symptoms, and the extent to which these symptoms were associated with serious maternal and fetal outcomes. The descriptive results of this study show that the majority (88%) of uterine ruptures occurred in the presence of labor and 77% were accompanied by maternal or fetal signs or symptoms (i.e. 23% were ‘‘silent’’). The sole patient characteristic significantly associated with silent rupture in laboring women was more than one prior CD. This is a clinically compelling finding that should be factored into clinical management of such patients. Among laboring patients, the prevalence of a FHR abnormality was 73%, which is consistent with the prevalence of FHR abnormalities reported in the literature (55–87%) [3]. While the types of FHR abnormalities varied, one-third of these cases (and 24% of all laboring women with uterine rupture) demonstrated a prolonged deceleration or bradycardia. Maternal signs or symptoms in laboring women were more unusual (17% of cases), and were predominantly associated with ‘‘crash’’ CD. Vaginal bleeding and abdominal pain were equally prevalent (7.6%), followed by a loss of station (4.6%). The occurrence of physical signs or symptoms appeared to be associated with
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Table 3. Patient complications associated with clinical signs or symptoms in laboring patients (N ¼ 66).
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Patients with signs or symptoms (N ¼ 51)
Patients without signs or symptoms (N ¼ 15)
MATERNAL *Bladder rupture (N ¼ 2) Chorioamnionitis (N ¼ 12) Chorioamnionitis + fourth degree perinatal laceration (N ¼ 1) *Chorioamnionitis + intestinal obstruction (N ¼ 1) *Cesarean hysterectomy (N ¼ 1) Cystoscopy (N ¼ 1) *Transfusion of packed red blood cells + chorioamnionitis (N ¼ 2) *Transfusion of packed red blood cells + fresh frozen plasma (N ¼ 1) None (N ¼ 30)
MATERNAL Chorioamnionitis (N ¼ 1) Uterine inversion (N ¼ 1) None (N ¼ 13)
NEONATAL *CNS symptoms + intubation (N ¼ 1) *CNS symptoms + perinatal infection (N ¼ 3) *CNS symptoms + perinatal infection + meconium aspiration (N ¼ 1) *CNS symptoms + respiratory distress syndrome + perinatal infection + ventilation + hypoglycemia (N ¼ 1) Infant of a diabetic mother (N ¼ 1) Infant of a diabetic mother + metabolic disturbance (N ¼ 1) *Meconium aspiration syndrome + respiratory distress syndrome (N ¼ 1) *Meconium (N ¼ 1) Meconium (N ¼ 1) Neonatal intensive care unit for weight criteria (N ¼ 1) *Perinatal infection (N ¼ 3) *Perinatal infection + intubation (N ¼ 1) Perinatal infection + intubation (N ¼ 1) *Perinatal infection + gastrointestinal hemorrhage (N ¼ 1) *Perinatal infection + meconium (N ¼ 1) *Respiratory distress syndrome (N ¼ 1) *Respiratory distress syndrome + perinatal infection + ventilation + hypoglycemia at 30 weeks’ gestational age (N ¼ 1) *Respiratory distress syndrome + infant of a diabetic mother (N ¼ 1) *Respiratory distress syndrome + perinatal infection (N ¼ 2) Respiratory distress syndrome + phototherapy (N ¼ 1) *Sepsis (N ¼ 1) *Sepsis + hypoglycemia (N ¼ 1) Substance use (N¼2) *Transient tachypnea of the newborn (N ¼ 2) None (N ¼ 20)
NEONATAL Infant of a diabetic mother (N ¼ 1) *Respiratory distress syndrome (N ¼ 1) *Respiratory distress syndrome + sepsis (N ¼ 1) Meconium (N ¼ 2) None (10)
Cases classified as severe are indicated by an asterisk.
a longer mean duration of ruptured membranes and admission-delivery time. Prolonged labor is known to be a risk factor for uterine rupture, and this excess time may also lead to further opportunities for FHR abnormalities to appear [2,9–11]. Of note, nearly all patients had epidural analgesia during labor (94%), but the duration of epidural analgesia was not associated with the appearance of physical signs or symptoms [9,12]. The analytical portion of this study demonstrated that laboring patients with physical signs or symptoms were seven times more likely than those without them to have a poor maternal or neonatal outcome. Although women with multiple prior cesarean deliveries initially appeared less likely to have Any Severe Childbirth Outcome, this relationship did not persist in the multivariable models, where only FHR late decelerations and bradycardia were retained as important risk factors. It is important to emphasize that such physical signs were associated with poor outcomes of patients undergoing uterine rupture and such information does not assist in determining who will undergo uterine rupture. FHR abnormalities, for example, are common findings in many labors that do not result in uterine rupture and the positive predictive value of such information is likely to be low. Furthermore,
severe outcomes were not causally linked to uterine rupture for each individual case, and it may be argued that some outcomes, e.g. respiratory distress or sepsis, did not directly result from uterine rupture. However, neonatal respiratory morbidity can be attributed to hypoxia caused by uterine rupture, and sepsis can contribute to the onset of neonatal encephalopathy [13]. A full developmental history of each neonate would have to be undertaken to determine definitive causation in each case. An important new finding in this study was the association of fetal tachycardia with poor maternal outcomes. This was highly associated with abruption, maternal blood loss and transfusion. Previous studies indicate that fetal tachycardia does not appear to distinguish cases of uterine rupture from non-rupture in women undergoing TOLAC [14]. Although documented physical signs and symptoms varied widely, the presence of at least one sign or symptom identified nearly all laboring patients (27/29 [93.1%]) with poor outcomes. Two cases of silent uterine ruptures during labor were associated with poor neonatal outcomes (including respiratory distress). Furthermore, recent evidence suggests that complete uterine ruptures can be ‘‘masked’’, whereby the rupture site may remain localized either externally
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Table 4. Risk factors for Severe Childbirth Outcomes in laboring women.
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Patient characteristics Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
Percent of Patients with ANY severe outcome who have characteristic (N ¼ 29)
5 (13.5%)
0.7383 0.0107
10 (34.5%) 18/42 (42.9%) 7/15 (46.7%) 4/9 (44.4%)
8 (21.6%)
0.2765 0.9674
8 9 12 5 23 3/29 6 10 10 5 10
(27.6%) (31.0%) (41.4%) (17.2%) (79.3%) (10.3%) (20.7%) (34.5%) (34.5%) (17.2%) (34.5%)
4 4 10 2 26 10/36 5 7 6 3 8
(10.8%) (10.8%) (27.0%) (5.4%) (70.3%) (27.8%) (13.5%) (18.9%) (16.2%) (18.1%) (21.6%)
Percent of Patients WITHOUT severe MATERNAL complication who have characteristic (N ¼ 59)
0.1521 0.0821 0.2942 0.2259 0.5717 0.1514 0.5153 0.1691 0.1466 0.2852 0.2765
p value
2 (28.6%) 0/3 (0%) 5/41 (12.2%) 2/7 (28.6%) 0/15 (0%)
8 (13.6%)
0.2853 0.2012
4 (57.1%) 3/42 (7.1%) 2/15 (13.3%) 2/9 (22.2%)
14 (23.7%)
0.0816 0.3810
3 (42.9%) 3 (42.9%) 2 (28.6%) 0 (0%) 6 (85.7%) 0/7 (0%) 2 (28.6%) 3(42.9%) 2 (28.6%) 3 (42.9%) 2 (28.6%) Percent of Patients with severe FETAL complication who have characteristic (N ¼ 25)
Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
p value
5 (17.2%) 1/3 (33.3%) 20/41 (48.8%) 6/7 (85.7%) 2/15 (13.3%)
Percent of Patients with Severe MATERNAL complication who have characteristic (N ¼ 7) Signs or symptoms on admission Sign or symptom category Mat Fetal Both None Crash Intervention stage First Second Postpartum Extrusion Abruption Induction Cervical ripening Oxytocin More than one prior cesarean delivery Any previous vaginal birth after cesarean Fetal heart rate late decelerations Fetal heart rate prolonged deceleration or bradycardia Fetal heart rate tachycardia Fetal heart rate variable decelerations
Percent of Patients WITHOUT ANY severe outcome who have characteristic (N ¼ 37)
9 10 20 7 43 13/58 9 14 14 5 16
(15.3%) (16.9%) (33.9%) (11.9%) (72.9%) (22.4%) (15.3%) (23.7%) (23.7%) (8.5%) (27.1%)
Percent of Patients WITHOUT severe FETAL complication who have characteristic (N ¼ 41)
0.1066 0.1314 1.0000 1.0000 0.6670 0.3287 0.3300 0.3618 1.0000 0.0344 1.0000
p value
3 (12.0%) 1/3 (33.3%) 16/41 (39.0%) 6/7 (85.7%) 2/15 (13.3%)
7 (17.1%)
0.7304 0.0135
8 (32.0%) 17/42 (40.5%) 5/15 (33.3%) 3/9 (33.3%)
10 (24.4%)
0.5740 0.3810
6 7 10 5/25 20 3/25 5/25 8 9 4 9
(24.0%) (28.0%) (40.0%) (20.0%) (80.0%) (12.0%) (20.0%) (32.0%) (36.0%) (16.0%) (36.0%)
5 5 12 2 29 10/40 6/41 9 7 4 9
(12.2%) (12.2%) (29.3%) (4.9%) (70.7%) (25.0%) (14.6%) (22.0%) (17.1%) (9.8%) (22.0%)
0.3082 0.1864 0.4258 0.0948 0.5634 0.3390 0.7352 0.3966 0.1372 0.4650 0.2603
Uterine rupture
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DOI: 10.3109/14767058.2014.954537
(e.g. through coverage by the omentum) or internally (e.g. through coverage by fetal parts), and maternal or fetal signs or symptoms may be undetected [15]. Given that nearly a quarter (23%) of laboring patients with uterine rupture had no maternal or fetal signs or symptoms, it is evident that physicians whose patients are undergoing TOLAC are unaware clinically of the impending rupture and are not always ‘‘put on notice’’ [16]. Furthermore, 35% of those who did have signs or symptoms underwent a ‘‘crash’’ CD, implying that there was little opportunity for earlier intervention. Duration of the insult is not the only a factor that may lead to poor outcomes, as the severity of the insult (e.g. whether or not placental abruption occurred) and the fetal status and reserves prior to the insult (e.g. whether intrauterine growth restriction or fetal acidemia were present) also likely contribute to fetal outcomes [17], and are often not measureable in retrospect. Of interest is that in the non-laboring group (N ¼ 9), all three cases with severe outcomes occurred in asymptomatic women. It has long been generally assumed that asymptomatic uterine scar rupture, or what has often been referred to as ‘‘dehiscence’’ is unassociated with maternal or neonatal morbidity, and there are few reports of uterine scar dehiscence rates or outcomes associated with such dehiscence, largely because women undergoing VBAC have not been systematically evaluated. Spong et al. [18], studying approximately 15 000 women from 19 institutions over four years, found the risk of uterine rupture to be 0.74% and the risk of uterine dehiscence to be 0.67% in women with singleton term pregnancies undergoing TOLAC. It is likely that the prevalence of a rupture of previous cesarean scar in our population was higher than expected (2.3%) because of the broad definition of uterine rupture used here. Even so, prior reports have shown varying prevalence depending on the definition and documentation, and have reached up to 3.7% among women undergoing TOLAC with more than one prior CD [1,9]. It is also likely that our higher prevalence of uterine rupture was due to practice patterns during the study period (e.g. more cervical ripening), as well as the high proportions of women with more than one prior uterine scar and with undocumented direction of prior uterine scar. Previously we have shown that labor induction in patients undergoing TOLAC may be a reasonable consideration in some patients [19]. The definition of uterine rupture has remained a subject of controversy over the years. The evidence report prepared for the Agency for Healthcare Research and Quality (AHRQ) regarding VBAC in 2003 documents the discussion held at a ‘‘Uterine Rupture Terminology Conference’’ in 2002, and found many inconsistencies and ambiguities in terminology used for uterine rupture [3]. There was some agreement on the following terms: ‘‘incomplete’’ uterine rupture of a cesarean scar – separation that was not completely through all layers of the uterine wall (e.g. serosa intact), and ‘‘complete’’ uterine rupture of a cesarean scar – entire thickness of the uterine wall including visceral serosa. The subsequent evidence report prepared for the AHRQ in 2010 focused on ‘‘complete’’ uterine rupture in order to compare similar studies [2]. However, the actual guidelines produced by the NIH
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Consensus Conference in 2010 state that ‘‘uterine rupture is defined as an anatomic separation of the uterine muscle with or without symptoms’’, and does not distinguish between complete and incomplete ruptures [1]. In the current study, we combined women with both complete and incomplete ruptures because: (1) medical record documentation often did not distinguish between the two, and (2) both complete and incomplete uterine ruptures were associated with maternal and fetal signs and symptoms and poor childbirth outcomes. Similar findings of under-reporting of uterine rupture secondary to abstraction from plain text (as opposed to ‘‘check boxes’’ or other structured reporting options) have been noted [20]. In summary, this study demonstrated that with the current NIH Consensus Conference definition of uterine rupture, 77% of laboring women undergoing TOLAC who experienced uterine rupture demonstrated maternal or fetal physical signs or symptoms before delivery. Although documented signs and symptoms varied widely, the presence of at least one sign or symptom identified nearly all cases (27/29 [93.1%]) with poor outcomes. Thus, in laboring patients with uterine rupture, lack of signs or symptoms appears to be reassuring. Conversely, 33% of non-laboring women (3/9 cases) had serious neonatal outcomes, and all these women were asymptomatic. Our finding regarding the relationship between fetal tachycardia and maternal symptoms was also clinically compelling and warrants further analysis. Finally, the documentation of uterine rupture and its associated physical signs and symptoms, timing, and outcomes, appears to be inadequate for research studies, and standardization should be a common goal across all health systems.
Declaration of interest The authors report no declarations of interest.
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