A C TA Obstetricia et Gynecologica
AOGS M A I N R E SE A RC H A R TI C LE
Is there an association between sonographically determined occipito-transverse position in the second stage of labor and operative delivery? HALA PHIPPS1,2,3, JON A. HYETT1,2, KATHY GRAHAM1, WENDY J. CARSELDINE1, JANE TOOHER1 & BRADLEY DE VRIES1,2 1
RPA Women and Babies, Royal Prince Alfred Hospital, 2Discipline of Obstetrics, Gynaecology and Neonatology, Faculty of Medicine, University of Sydney, and 3Faculty of Nursing, University of Sydney, Sydney, New South Wales, Australia
Key words Occipito-transverse position, occipito-anterior position, operative delivery, cesarean section, instrumental delivery, ultrasound Correspondence Hala Phipps, Discipline of Obstetrics, Gynaecology and Neonatology, RPA Women and Babies, Royal Prince Alfred Hospital, Sydney, New South Wales 2050, Australia. E-mail: [email protected] Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article. Please cite this article as: Phipps H, Hyett JA, Graham K, Carseldine WJ, Tooher J, de Vries B. Is there an association between sonographically determined occipitotransverse position in the second stage of labor and operative delivery?. Acta Obstet Gynecol Scand 2014; 93: 1018–1024. Received: 23 December 2013 Accepted: 16 July 2014
Abstract Objective. To evaluate if ultrasound-determined occipito-transverse position early in the second stage of labor is associated with operative delivery. Design. Retrospective review of two prospective cohort studies. Setting. An Australian tertiary referral hospital. Population. Women with term, cephalic singleton pregnancies. Methods. Retrospective analysis of data from two prospective studies. Logistic regression was undertaken to assess the independent contribution of the occipito-transverse position to operative delivery. Main outcome measure. Operative delivery (cesarean section, forceps or vacuum extraction). Results. Among 422 women included, the occipito-transverse position was present in 80, occipito-anterior in 303 and the occipito-posterior in 39. Compared with occipito-anterior, the adjusted odds ratio for operative delivery was 2.1 (95% confidence interval 1.2–3.8, p = 0.02) for the occipitotransverse position, and 7.4 (95% confidence interval 3.2–17) for the occipitoposterior position. Factors that independently predicted operative delivery were nulliparity, abnormal second stage cardiotocography, maternal place of birth and epidural analgesia. The length of second stage of labor was longer for the occipito-transverse group than for the occipito-anterior group (median 2 h 7 min vs. 1 h 36 min, p = 0.003). Conclusion. The occipito-transverse position early in the second stage of labor was associated with an increased operative delivery rate. CTG, cardiotocography; IQR, interquartile range; OA, occipitoanterior; OP, occipito-posterior; OT, occipito-transverse.
Abbreviations:
DOI: 10.1111/aogs.12465
(3,5), 10 and 20% in the second stage of labor (2,5,6) and 3 and 8% at delivery (3,5). There is scant evidence on the actual operative delivery rates when the OT
Introduction Occipito-transverse (OT) position is an important determinant of the mode of delivery (1) and represents the most common malposition during labor (2,3). The OT position has long been associated with deep transverse arrest requiring cesarean section (CS) or operative vaginal delivery (4). The prevalence of the OT position has been estimated at between 19 and 49% at the onset of labor
1018
Key Message The occipito-transverse position early in the second stage of labor is associated with increased risk for operative delivery.
ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
H. Phipps et al.
position is present early in the second stage of labor. Most studies have grouped OT with the occipito-posterior (OP) or occipito-anterior (OA) positions and the independent impact of the OT position has not been assessed (7–10). Cesarean section is associated with significant morbidity and even mortality in both the current and future pregnancies (11). Instrumental delivery is associated with trauma to the maternal genital tract and a number of neonatal complications (12). The OT position itself is associated with obstetric complications in labor and delivery including more frequent augmentation of labor, episiotomy, third/fourth-degree perineal trauma, febrile morbidity, prolonged second stage of labor, and low 5-min Apgar scores (1). Intrapartum ultrasound plays an important role in modern obstetrics and is more accurate than vaginal examination for determining fetal position in labor (13). The aim of this study was to assess the operative delivery rate for ultrasound-determined OT position in second stage of labor compared with the OA and OP positions and to describe the association between OT position and other adverse maternal and fetal/neonatal outcomes.
Material and methods This cohort study was conducted at a tertiary referral hospital in Sydney between February 2008 and December 2011. The primary study factor was OT position diagnosed on transabdominal ultrasound within 30 min of full cervical dilatation and the primary outcome was operative delivery defined as vacuum extraction, forceps use or CS. The study used prospectively collected data from two previous reports. The first, a blinded prospective cohort study (February 2008 to April 2009) examined the impact of ultrasound-determined OP position early in the second stage of labor on the mode of delivery (14). In this study, the outcomes for OP position (n = 19) were compared with those for OA position (n = 160) and data were available for an additional 39 fetuses in the OT position. The second, a pilot randomized controlled trial of attempted manual rotation from the OP to the OA position in the second stage of labor (December 2010 to December 2011), also required a screening transabdominal ultrasound early in the second stage of labor (15). In this study, data were available for 143 fetuses in the OA position, 41 in the OT position and 20 in the OP position. Women randomized to manual rotation were excluded from the current study. Women were included in the study if they had completed at least 37 weeks of gestation with a cephalic singleton pregnancy, planned a vaginal delivery, had a
Occipito-transverse position and operative delivery
cervix at full dilatation with position of the fetal head confirmed by a transabdominal ultrasound scan (mobile device), were more than 16 years old and had given written informed consent before the onset of active labor. Women were excluded if there was a clinical suspicion of cephalo-pelvic disproportion, a history of previous uterine surgery (CS, open or laparoscopic myomectomy), a brow or face presentation, a pathological cardiotocography (CTG) recording according to the RCOG guidelines (16), plus either cardiotocographic abnormal baseline or reduced variability for more than 90 min, suspected fetal compromise, an anatomical fetal abnormality, suspected or known chorioamnionitis, any condition requiring immediate delivery, intrapartum hemorrhage >50 mL, temperature >38.5°C in labor or a suspected fetal bleeding diathesis. Potential participants were given an information sheet at their 35–37-week antenatal clinic visit to the hospital, and gave written informed consent either antenatally or in the early stages of labor (cervical dilatation 45° from the midline) (3).
Statistical analysis Independent t-tests for continuous data were performed in the univariate analysis using SAS/STAT software version 9.2 (Cary, NC, USA). Normally distributed data were expressed as means SD and non-normally distributed continuous data were expressed as medians and IQRs. Logistic regression analysis was performed to assess the independent contribution of OT and OP positions to operative delivery. Values of p < 0.05 were considered significant. Factors considered for inclusion in the logistic model were: fetal head position (OA, OT or OP), maternal age, parity (nulliparous or parous), gestational age, maternal place of birth (categorized as in Table 1), induction of labor, epidural in labor, commencement of
oxytocin in the first stage of labor, and classification of CTG in the second stage of labor [as (a) none/normal or suspicious, (b) pathological with normal baseline and variability, or (c) pathological with abnormal baseline or reduced variability >90 min (15)]. Continuous variables were tested for linear association with the logit function of the outcome by plotting b-coefficients against the midpoints of quartiles. When the assumption of linearity was not met, an explanatory variable was divided into ordered categories. Interaction was assessed by creating multiplication terms and using p < 0.01 as evidence of interaction. Non-confounders were removed in a stepwise manner until only the study factor (position of the fetal occiput) and confounders remained. A second, post-hoc logistic regression was performed that included fetal station as an additional explanatory variable [as (a) above the ischial spines, (b) at the ischial spines, or (c) below the ischial spines]. This variable was not considered initially because it was not routinely recorded by the clinician who performed the vaginal examination. Ethics approval for both studies was obtained by the Hospital Ethics Review Committee (Protocols X07-0173 and X10-0091).
Results In all, 422 women were included. Of them, 80 had a fetus in the OT position, 303 in the OA position and 39 in the OP position, as diagnosed by transabdominal ultrasound
Table 1. Maternal demographic and labor characteristics according to fetal position at full dilatation.
Maternal age (years) Maternal BMI (kg/m2) Ethnicity “Western”a South East Asia Other Gestational age at delivery (days) Nulliparous Gestational hypertension Gestational diabetes Induction of labor Epidural analgesia Thick meconium Second stage cardiotocography Normal/suspicious Pathological (normal baseline/variability) Pathological (abnormal baseline/variability)
Occipito-transverse (n = 80)
Occipito-anterior (n = 303)
p-valueb
Occipito-posterior (n = 39)
31.1 4.9 22.5 (19.9–25.6)
31.9 4.6 22.5 (20.6–25.6)
0.181 0.752
31.7 4.6 23.9 (21.9–26.5)
40 29 11 280 66 3 6 31 19 11
(50) (36) (14) (276–285) (83) (4) (8) (39) (24) (14)
136 (45) 142 (47) 25 (8)
208 60 35 281 223 27 34 109 67 39
(69) (20) (12) (274–286) (74) (9) (11) (36) (22) (13)
14 (36) 18 (46) 7 (18)
0.0043
0.642 0.103 0.133 0.333 0.653 0.753 0.563 0.0083
33 5 1 283 30 5 1 16 32 5
(85) (13) (3) (277–289) (77) (13) (3) (41) (82) (13)
47 (59) 22 (28) 11 (14)
Data are given as n (%); mean SD for parametric variables; and median (interquartile range) for nonparametric variables. Australia/New Zealand/North America/Europe. b Statistical tests as follows: 1t-test; 2Wilcoxon rank sum test; 3Chi-squared test. a
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ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
H. Phipps et al.
Occipito-transverse position and operative delivery
early in the second stage of labor. The OT and OA groups had similar maternal demographics except for higher representation among women from South East Asia in the OT group (Table 1). There were no significant differences in clinical and labor characteristics between women with a fetus in the OT and the OA positions, including parity, gestational hypertension or diabetes, induction of labor and epidural anesthesia in labor (Table 1). In the univariate analysis, the overall operative delivery rate for the OT position early in the second stage was 49%, compared with 31% for the OA group (p = 0.003) and 71% in the OP group (Table 2). CS was performed in 11 and 5% in the OT and OA groups, respectively (p = 0.03), and 28% in the OP group (Table 2). The median length of the second stage was 2 h 7 min in the OT group (IQR 73–195 min) and 1 h 36 min in the OA group (IQR 52–148 min) (Wilcoxon rank sum test, p = 0.003) (Table 2). Third- or fourthdegree tears occurred in 9% of the OT group and 4% of the OA group (p = 0.28). The median blood loss was 350 mL (IQR 300–450 mL) in the OT group compared with 300 mL (IQR 200–400 mL) in the OA group (Wilcoxon rank sum test p = 0.003) (Table 3). There was no difference between the groups in parity, gestational hypertension and diabetes, induction of labor, epidural analgesia, thick meconium, Apgar scores, cord pH or admission to the neonatal intensive care unit (Tables 1 and 3). A logistic regression was performed for the primary outcome, operative delivery. Variables were included in the base model if p < 0.25 in the univariate analysis or
there was prior knowledge of an association with operative delivery. These variables were: fetal head position (OT, OA or OP), parity (nulliparous or parous), gestational age, maternal place of birth (categorized as in Table 1), induction of labor, epidural in labor, commencement of oxytocin in the first stage of labor, and classification of CTG in the second stage of labor as described above. There was no evidence of interaction between position of the fetal occiput and any of the other variables. In the final model, fetal position, previous vaginal delivery, place of birth, epidural, abnormal second stage CTG, and epidural analgesia were independent predictors for operative delivery [OR 2.1 (95% CI 1.2–3.8, p = 0.02) for OT vs. OA and 7.4 (95% CI 3.2–17, p < 0.001) for OP vs. OA] (Table 4). A total of 275 sets of data were available for the post hoc logistic regression that included fetal station on vaginal examination as an additional categorical explanatory variable. In the final model, fetal station, fetal position, previous vaginal delivery, maternal education level, epidural analgesia and abnormal second stage CTG were independent predictors for operative delivery, i.e. OR 2.2 (95% CI 1.03–4.7) for OT vs. OA and OR 8.7 (95% CI 2.8–27) for OP vs. OA; and OR 0.54 (95% CI 0.19–1.6) for station at ischial spines vs. above ischial spines and OR 0.24 (95% CI 0.0– 0.71) for station below the ischial spines vs. above the ischial spines. As has been previously described (14), women enrolled in our study were more likely to be nulliparous, have their labor induced, have epidural analgesia and/or have an operative delivery compared with other women who delivered over the same time period.
Table 2. Delivery outcomes according to fetal position at full dilatation. Occipito-transverse (n = 80) Operative delivery Mode of delivery Caesarean section Forceps Vacuum extraction Operative delivery for failure to progress Length of labor First stage (min) Second stage (min) Perineal trauma Intact/first degree Second degree Third/Fourth degree Vaginal or labial tear Blood loss (mL)
Occipito-anterior (n = 303)
p-valuea
Occipito-posterior (n = 39)
39 (49)
93 (31)
0.0031
28 (71)
9 16 14 15
14 38 41 40
0.011
11 8 9 14
(11) (20) (18) (19)
(5) (13) (14) (13)
0.211
(28) (20) (23) (52)
285 (189–497) 127 (73–195)
300 (180–420) 96 (52–148)
0.192 0.0032
320 (210–570) 168 (137–217)
22 51 7 9 350
89 201 13 56 300
0.281
18 16 5 6 300
(28) (64) (9) (11) (300–450)
(29) (66) (4) (18) (200–400)
0.0031 0.0032
(46) (41) (13) (15) (200–600)
Data are given as n (%) or median (interquartile range). Statistical tests as follows: 1Chi-squared test; 2Wilcoxon rank sum test.
a
ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
1021
Occipito-transverse position and operative delivery
H. Phipps et al.
Table 3. Neonatal outcomes according to fetal positions at full dilatation. Occipito-transverse (n = 80)
Occipito-anterior (n = 303)
p-Valuea
Occipito-posterior (n = 39)
3487 444 9 (9–9) 7.19 0.0 8 4 (5) 6 (8) 32 (40)
3486 436 9 (9–9) 7.19 0.08 13 (5) 18 (6) 140 (46)
0.991 0.682 0.732 0.763 0.613 0.323
3692 405.5 9 (9–9) 7.20 0.07 2 (5%) 3 (8%) 19 (49)
Birthweight APGAR at 5 min (IQR) Cord pH (SD)b Phototherapy NICU admission Male infant
Data are given as n (%) mean SD for parametric variables median (IQR) for nonparametric variables. Statistical tests as follows: 1t-test; 2Wilcoxon rank sum test; 3Chi-squared analysis. b Only 33/39 occipito-transverse had arterial cord pH measurements. a
Table 4. Factors associated with operative delivery in the logistic regression model. Variable
Adjusted OR
Fetal head position Occipito-anterior Occipito-transverse Occipito-posterior Parity Nulliparous Multiparous Epidural No epidural Epidural Second-stage cardiotocography Normal/suspicious Pathological (normal baseline/variability)b Pathological (abnormal baseline/variability)b
95% CI
p
AOGS M A I N R E SE A RC H A R TI C LE
Is there an association between sonographically determined occipito-transverse position in the second stage of labor and operative delivery? HALA PHIPPS1,2,3, JON A. HYETT1,2, KATHY GRAHAM1, WENDY J. CARSELDINE1, JANE TOOHER1 & BRADLEY DE VRIES1,2 1
RPA Women and Babies, Royal Prince Alfred Hospital, 2Discipline of Obstetrics, Gynaecology and Neonatology, Faculty of Medicine, University of Sydney, and 3Faculty of Nursing, University of Sydney, Sydney, New South Wales, Australia
Key words Occipito-transverse position, occipito-anterior position, operative delivery, cesarean section, instrumental delivery, ultrasound Correspondence Hala Phipps, Discipline of Obstetrics, Gynaecology and Neonatology, RPA Women and Babies, Royal Prince Alfred Hospital, Sydney, New South Wales 2050, Australia. E-mail: [email protected] Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article. Please cite this article as: Phipps H, Hyett JA, Graham K, Carseldine WJ, Tooher J, de Vries B. Is there an association between sonographically determined occipitotransverse position in the second stage of labor and operative delivery?. Acta Obstet Gynecol Scand 2014; 93: 1018–1024. Received: 23 December 2013 Accepted: 16 July 2014
Abstract Objective. To evaluate if ultrasound-determined occipito-transverse position early in the second stage of labor is associated with operative delivery. Design. Retrospective review of two prospective cohort studies. Setting. An Australian tertiary referral hospital. Population. Women with term, cephalic singleton pregnancies. Methods. Retrospective analysis of data from two prospective studies. Logistic regression was undertaken to assess the independent contribution of the occipito-transverse position to operative delivery. Main outcome measure. Operative delivery (cesarean section, forceps or vacuum extraction). Results. Among 422 women included, the occipito-transverse position was present in 80, occipito-anterior in 303 and the occipito-posterior in 39. Compared with occipito-anterior, the adjusted odds ratio for operative delivery was 2.1 (95% confidence interval 1.2–3.8, p = 0.02) for the occipitotransverse position, and 7.4 (95% confidence interval 3.2–17) for the occipitoposterior position. Factors that independently predicted operative delivery were nulliparity, abnormal second stage cardiotocography, maternal place of birth and epidural analgesia. The length of second stage of labor was longer for the occipito-transverse group than for the occipito-anterior group (median 2 h 7 min vs. 1 h 36 min, p = 0.003). Conclusion. The occipito-transverse position early in the second stage of labor was associated with an increased operative delivery rate. CTG, cardiotocography; IQR, interquartile range; OA, occipitoanterior; OP, occipito-posterior; OT, occipito-transverse.
Abbreviations:
DOI: 10.1111/aogs.12465
(3,5), 10 and 20% in the second stage of labor (2,5,6) and 3 and 8% at delivery (3,5). There is scant evidence on the actual operative delivery rates when the OT
Introduction Occipito-transverse (OT) position is an important determinant of the mode of delivery (1) and represents the most common malposition during labor (2,3). The OT position has long been associated with deep transverse arrest requiring cesarean section (CS) or operative vaginal delivery (4). The prevalence of the OT position has been estimated at between 19 and 49% at the onset of labor
1018
Key Message The occipito-transverse position early in the second stage of labor is associated with increased risk for operative delivery.
ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
H. Phipps et al.
position is present early in the second stage of labor. Most studies have grouped OT with the occipito-posterior (OP) or occipito-anterior (OA) positions and the independent impact of the OT position has not been assessed (7–10). Cesarean section is associated with significant morbidity and even mortality in both the current and future pregnancies (11). Instrumental delivery is associated with trauma to the maternal genital tract and a number of neonatal complications (12). The OT position itself is associated with obstetric complications in labor and delivery including more frequent augmentation of labor, episiotomy, third/fourth-degree perineal trauma, febrile morbidity, prolonged second stage of labor, and low 5-min Apgar scores (1). Intrapartum ultrasound plays an important role in modern obstetrics and is more accurate than vaginal examination for determining fetal position in labor (13). The aim of this study was to assess the operative delivery rate for ultrasound-determined OT position in second stage of labor compared with the OA and OP positions and to describe the association between OT position and other adverse maternal and fetal/neonatal outcomes.
Material and methods This cohort study was conducted at a tertiary referral hospital in Sydney between February 2008 and December 2011. The primary study factor was OT position diagnosed on transabdominal ultrasound within 30 min of full cervical dilatation and the primary outcome was operative delivery defined as vacuum extraction, forceps use or CS. The study used prospectively collected data from two previous reports. The first, a blinded prospective cohort study (February 2008 to April 2009) examined the impact of ultrasound-determined OP position early in the second stage of labor on the mode of delivery (14). In this study, the outcomes for OP position (n = 19) were compared with those for OA position (n = 160) and data were available for an additional 39 fetuses in the OT position. The second, a pilot randomized controlled trial of attempted manual rotation from the OP to the OA position in the second stage of labor (December 2010 to December 2011), also required a screening transabdominal ultrasound early in the second stage of labor (15). In this study, data were available for 143 fetuses in the OA position, 41 in the OT position and 20 in the OP position. Women randomized to manual rotation were excluded from the current study. Women were included in the study if they had completed at least 37 weeks of gestation with a cephalic singleton pregnancy, planned a vaginal delivery, had a
Occipito-transverse position and operative delivery
cervix at full dilatation with position of the fetal head confirmed by a transabdominal ultrasound scan (mobile device), were more than 16 years old and had given written informed consent before the onset of active labor. Women were excluded if there was a clinical suspicion of cephalo-pelvic disproportion, a history of previous uterine surgery (CS, open or laparoscopic myomectomy), a brow or face presentation, a pathological cardiotocography (CTG) recording according to the RCOG guidelines (16), plus either cardiotocographic abnormal baseline or reduced variability for more than 90 min, suspected fetal compromise, an anatomical fetal abnormality, suspected or known chorioamnionitis, any condition requiring immediate delivery, intrapartum hemorrhage >50 mL, temperature >38.5°C in labor or a suspected fetal bleeding diathesis. Potential participants were given an information sheet at their 35–37-week antenatal clinic visit to the hospital, and gave written informed consent either antenatally or in the early stages of labor (cervical dilatation 45° from the midline) (3).
Statistical analysis Independent t-tests for continuous data were performed in the univariate analysis using SAS/STAT software version 9.2 (Cary, NC, USA). Normally distributed data were expressed as means SD and non-normally distributed continuous data were expressed as medians and IQRs. Logistic regression analysis was performed to assess the independent contribution of OT and OP positions to operative delivery. Values of p < 0.05 were considered significant. Factors considered for inclusion in the logistic model were: fetal head position (OA, OT or OP), maternal age, parity (nulliparous or parous), gestational age, maternal place of birth (categorized as in Table 1), induction of labor, epidural in labor, commencement of
oxytocin in the first stage of labor, and classification of CTG in the second stage of labor [as (a) none/normal or suspicious, (b) pathological with normal baseline and variability, or (c) pathological with abnormal baseline or reduced variability >90 min (15)]. Continuous variables were tested for linear association with the logit function of the outcome by plotting b-coefficients against the midpoints of quartiles. When the assumption of linearity was not met, an explanatory variable was divided into ordered categories. Interaction was assessed by creating multiplication terms and using p < 0.01 as evidence of interaction. Non-confounders were removed in a stepwise manner until only the study factor (position of the fetal occiput) and confounders remained. A second, post-hoc logistic regression was performed that included fetal station as an additional explanatory variable [as (a) above the ischial spines, (b) at the ischial spines, or (c) below the ischial spines]. This variable was not considered initially because it was not routinely recorded by the clinician who performed the vaginal examination. Ethics approval for both studies was obtained by the Hospital Ethics Review Committee (Protocols X07-0173 and X10-0091).
Results In all, 422 women were included. Of them, 80 had a fetus in the OT position, 303 in the OA position and 39 in the OP position, as diagnosed by transabdominal ultrasound
Table 1. Maternal demographic and labor characteristics according to fetal position at full dilatation.
Maternal age (years) Maternal BMI (kg/m2) Ethnicity “Western”a South East Asia Other Gestational age at delivery (days) Nulliparous Gestational hypertension Gestational diabetes Induction of labor Epidural analgesia Thick meconium Second stage cardiotocography Normal/suspicious Pathological (normal baseline/variability) Pathological (abnormal baseline/variability)
Occipito-transverse (n = 80)
Occipito-anterior (n = 303)
p-valueb
Occipito-posterior (n = 39)
31.1 4.9 22.5 (19.9–25.6)
31.9 4.6 22.5 (20.6–25.6)
0.181 0.752
31.7 4.6 23.9 (21.9–26.5)
40 29 11 280 66 3 6 31 19 11
(50) (36) (14) (276–285) (83) (4) (8) (39) (24) (14)
136 (45) 142 (47) 25 (8)
208 60 35 281 223 27 34 109 67 39
(69) (20) (12) (274–286) (74) (9) (11) (36) (22) (13)
14 (36) 18 (46) 7 (18)
0.0043
0.642 0.103 0.133 0.333 0.653 0.753 0.563 0.0083
33 5 1 283 30 5 1 16 32 5
(85) (13) (3) (277–289) (77) (13) (3) (41) (82) (13)
47 (59) 22 (28) 11 (14)
Data are given as n (%); mean SD for parametric variables; and median (interquartile range) for nonparametric variables. Australia/New Zealand/North America/Europe. b Statistical tests as follows: 1t-test; 2Wilcoxon rank sum test; 3Chi-squared test. a
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ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
H. Phipps et al.
Occipito-transverse position and operative delivery
early in the second stage of labor. The OT and OA groups had similar maternal demographics except for higher representation among women from South East Asia in the OT group (Table 1). There were no significant differences in clinical and labor characteristics between women with a fetus in the OT and the OA positions, including parity, gestational hypertension or diabetes, induction of labor and epidural anesthesia in labor (Table 1). In the univariate analysis, the overall operative delivery rate for the OT position early in the second stage was 49%, compared with 31% for the OA group (p = 0.003) and 71% in the OP group (Table 2). CS was performed in 11 and 5% in the OT and OA groups, respectively (p = 0.03), and 28% in the OP group (Table 2). The median length of the second stage was 2 h 7 min in the OT group (IQR 73–195 min) and 1 h 36 min in the OA group (IQR 52–148 min) (Wilcoxon rank sum test, p = 0.003) (Table 2). Third- or fourthdegree tears occurred in 9% of the OT group and 4% of the OA group (p = 0.28). The median blood loss was 350 mL (IQR 300–450 mL) in the OT group compared with 300 mL (IQR 200–400 mL) in the OA group (Wilcoxon rank sum test p = 0.003) (Table 3). There was no difference between the groups in parity, gestational hypertension and diabetes, induction of labor, epidural analgesia, thick meconium, Apgar scores, cord pH or admission to the neonatal intensive care unit (Tables 1 and 3). A logistic regression was performed for the primary outcome, operative delivery. Variables were included in the base model if p < 0.25 in the univariate analysis or
there was prior knowledge of an association with operative delivery. These variables were: fetal head position (OT, OA or OP), parity (nulliparous or parous), gestational age, maternal place of birth (categorized as in Table 1), induction of labor, epidural in labor, commencement of oxytocin in the first stage of labor, and classification of CTG in the second stage of labor as described above. There was no evidence of interaction between position of the fetal occiput and any of the other variables. In the final model, fetal position, previous vaginal delivery, place of birth, epidural, abnormal second stage CTG, and epidural analgesia were independent predictors for operative delivery [OR 2.1 (95% CI 1.2–3.8, p = 0.02) for OT vs. OA and 7.4 (95% CI 3.2–17, p < 0.001) for OP vs. OA] (Table 4). A total of 275 sets of data were available for the post hoc logistic regression that included fetal station on vaginal examination as an additional categorical explanatory variable. In the final model, fetal station, fetal position, previous vaginal delivery, maternal education level, epidural analgesia and abnormal second stage CTG were independent predictors for operative delivery, i.e. OR 2.2 (95% CI 1.03–4.7) for OT vs. OA and OR 8.7 (95% CI 2.8–27) for OP vs. OA; and OR 0.54 (95% CI 0.19–1.6) for station at ischial spines vs. above ischial spines and OR 0.24 (95% CI 0.0– 0.71) for station below the ischial spines vs. above the ischial spines. As has been previously described (14), women enrolled in our study were more likely to be nulliparous, have their labor induced, have epidural analgesia and/or have an operative delivery compared with other women who delivered over the same time period.
Table 2. Delivery outcomes according to fetal position at full dilatation. Occipito-transverse (n = 80) Operative delivery Mode of delivery Caesarean section Forceps Vacuum extraction Operative delivery for failure to progress Length of labor First stage (min) Second stage (min) Perineal trauma Intact/first degree Second degree Third/Fourth degree Vaginal or labial tear Blood loss (mL)
Occipito-anterior (n = 303)
p-valuea
Occipito-posterior (n = 39)
39 (49)
93 (31)
0.0031
28 (71)
9 16 14 15
14 38 41 40
0.011
11 8 9 14
(11) (20) (18) (19)
(5) (13) (14) (13)
0.211
(28) (20) (23) (52)
285 (189–497) 127 (73–195)
300 (180–420) 96 (52–148)
0.192 0.0032
320 (210–570) 168 (137–217)
22 51 7 9 350
89 201 13 56 300
0.281
18 16 5 6 300
(28) (64) (9) (11) (300–450)
(29) (66) (4) (18) (200–400)
0.0031 0.0032
(46) (41) (13) (15) (200–600)
Data are given as n (%) or median (interquartile range). Statistical tests as follows: 1Chi-squared test; 2Wilcoxon rank sum test.
a
ª 2014 Nordic Federation of Societies of Obstetrics and Gynecology, Acta Obstetricia et Gynecologica Scandinavica 93 (2014) 1018–1024
1021
Occipito-transverse position and operative delivery
H. Phipps et al.
Table 3. Neonatal outcomes according to fetal positions at full dilatation. Occipito-transverse (n = 80)
Occipito-anterior (n = 303)
p-Valuea
Occipito-posterior (n = 39)
3487 444 9 (9–9) 7.19 0.0 8 4 (5) 6 (8) 32 (40)
3486 436 9 (9–9) 7.19 0.08 13 (5) 18 (6) 140 (46)
0.991 0.682 0.732 0.763 0.613 0.323
3692 405.5 9 (9–9) 7.20 0.07 2 (5%) 3 (8%) 19 (49)
Birthweight APGAR at 5 min (IQR) Cord pH (SD)b Phototherapy NICU admission Male infant
Data are given as n (%) mean SD for parametric variables median (IQR) for nonparametric variables. Statistical tests as follows: 1t-test; 2Wilcoxon rank sum test; 3Chi-squared analysis. b Only 33/39 occipito-transverse had arterial cord pH measurements. a
Table 4. Factors associated with operative delivery in the logistic regression model. Variable
Adjusted OR
Fetal head position Occipito-anterior Occipito-transverse Occipito-posterior Parity Nulliparous Multiparous Epidural No epidural Epidural Second-stage cardiotocography Normal/suspicious Pathological (normal baseline/variability)b Pathological (abnormal baseline/variability)b
95% CI
p
