Cases with ruptured membranes that "reseal" John W. C. Johnson, MD, Robert S. Egerman, MD, and Jacquelyn Moorhead, MStat Gainesville, Florida Among patients with a diagnosis of preterm prepartal rupture of the membranes, an occasional case ceases to leak amniotic fluid before the onset of labor. The purpose of this case-control study was to determine the characteristics and obstetric outcomes of this unique group of patients. This diagnosis was made in 24 such patients who gave birth in 1984 and 1985 at Shands Hospital. Compared with matched control subjects who continued to leak fluid, there were no significant differences in maternal race, age, marital status, socioeconomic status, smoking status, or past obstetric performance. Amniotic fluid volumes, as assessed by ultrasound studies, were less in the group that failed to "reseal." The "reseal" group had longer durations of pregnancy, larger babies, longer maternal hospitalization, less neonatal hospitalization, and less perinatal mortality and morbidity. The occurrence of "resealing" appears to bode well for the mother and infant. Such cases should be sought aggressively but managed conservatively. (AM J OBSTET GVNECOL 1990;163:1024-32.)
Key words: Ruptured membranes that "reseal," cessation of leakage of amniotic fluid, chorioamnion injury and repair Preterm prepartal rupture of the membranes continues to be an obstetric enigma in terms of cause and management. This is a frequent problem that complicates 8% to 25% of all pregnancies. I Yet there are still major disagreements as to when intervention for delivery should occur and whether antibiotics, steroids, or tocolytic agents should be used. I·' There is one outcome that occurs occasionally, which could have important implications in management. That is preterm prepartal rupture of the membranes with subsequent cessation of leakage of fluid and continuation of the pregnancy. We designate such patients as having had rupture of the membranes that "reseal," although other mechanisms could account for the discontinuation of vaginal amniotic fluid loss and remain to be evaluated. To our knowledge, the characteristics . and prognosis of cases that "reseal" have not been described in detail. Information concerning these patients could prove useful in selecting the best management for preterm prepartal rupture of the membranes and might provide insight into the cause. The purpose of this study was to determine in our patient population the frequency of such cases, their epidemiologic features, their obstetric characteristics (including amniotic fluid volumes as assessed by ultrasonographic studies), and their clinical course. From the Department of Obstetrics and Gynecology, College of Medicine, and the Department of Statistics, University of Florida. Presented as Official Guest at the Fifty-second Annual Meeting of the South Atlantic Association of Obstetricians and Gynecologists. Palm Beach. Florida. january 28-31, 1990. Reprint requests: john W. C. johnson, MD, Box ]-294, jHMHC, University of Florida College of Medicine, Gainesville, FL
32610.
6/6/22148
1024
Material and methods This case-control study was performed in patients giving birth at Shands Hospital during the years 1984 and 1985. There were 24 study cases with a diagnosis of preterm prepartal rupture of the membranes that subsequently "resealed" with continuation of the pregnancy (study group). Twenty-four women who had preterm prepartal rupture of the membranes but did not "reseal" (control group) were matched to the study group with regard to gestational age at the time of rupture and approximate calendar month of rupture. Data were abstracted from the medical records and included: (1) demographic factors, vital statistics, and socioeconomic indicators; (2) details of past obstetric performance; and (3) characteristics and outcomes of the current pregnancy. All 24 of the study cases and the 24 control cases were singleton pregnancies. Therefore data concerning multiple gestations were excluded from these analyses. The duration of pregnancy was assigned on the basis of the best estimate derived from menstrual data, early maternal physical examination, early ultrasonographic findings, and the infant's physical and neurologic development. The diagnosis of pre term prepartal rupture of the membranes was based on the history of sudden onset and continued vaginal leakage of fluid, which was confirmed by examination and positive ferning or alkaline testing with Nitrazine paper.' Patients with a diagnosis of prepartal rupture of the membranes were routinely hospitalized. In these patients the diagnosis of "resealing" was determined by daily inquiry of cessation of vaginal loss of fluid and by findings on speculum examination of absence of leakage and negative ferning or Nitrazine testing. Patients
Volume 163 Number 3
with a diagnosis of "resealed" were discharged to outpatient care. Ultrasonographic studies were performed routinely on most patients with suspected preterm prepartal rupture of the membranes at the time of admission with an ADR model 4000 scanner (Advanced Technology Laboratories, Inc., Bothell, Wash.) that used standard 3.5 or 5 MHz linear transducers. Amniotic fluid volumes were quantitated according to a previously described method" An obvious but slight decrease was designated as "one arrow down." If there was fluid behind the fetal back, but the largest vertical pocket measured 3 to 5 cm, the interpretation was a moderate decrease in amniotic fluid volume, designated as "two arrows down." If there was no fluid behind the fetal back and the largest vertical pocket measured only I to 3 cm, the interpretation was a marked decrease, designated as "three arrows down." The most severe decrease in amniotic fluid (oligohydramnios) was diagnosed if there was no fluid behind the fetal back and the largest vertical pocket was less than I cm in depth. This was designated as "four arrows down." Cervical or vaginal cultures for gonorrhea and group B streptococci were obtained on admission. In the event that either culture proved positive, appropriate antibiotic therapy was instituted. Otherwise, and in the absence of choreoamnionitis, antibiotics were not administered. As a general routine during 1984 and 1985, patients with preterm prepartal rupture of the membranes were not treated with tocolytic agents or steroids. Group comparisons were made with regard to maternal age, past obstetric peformance, race, level of maternal education, marital status, and history of substance abuse. Comparisons were also made between the two groups with regard to: (1) admission characteristics including maternal habitus expressed as weight-toheight ratio, hematocrit, white blood cell count, and ultrasound estimates of amniotic fluid volumes and (2) outcome variables including length of gestation at delivery, fetal birth weight, fetal sex, Apgar scores, perinatal outcome including mortality and neonatal morbidity, and duration of maternal and neonatal hospital stays. All statistical analyses were carried out by means of the Statistical Analysis Systems,S a computer software system for data analysis. For the continuous variables of interest a t test was performed to detect significant differences between the case and control group means. For nominal variables a X2 test was performed to test the independence of the outcome variable ("reseal") with the variables of interest. The Wilcoxon ranksum test was performed for the ordinal response variables. Kendall's tau b test was used for significant linear associations. Since several tests were performed and
Cases with ruptured membranes that "reseal"
1025
Table I. Gestational age at onset of rupture Preterm prepartal rupture of membrane, 1984-1985 Gestational age at membrane rupture (wh)
(n
Key words: Ruptured membranes that "reseal," cessation of leakage of amniotic fluid, chorioamnion injury and repair Preterm prepartal rupture of the membranes continues to be an obstetric enigma in terms of cause and management. This is a frequent problem that complicates 8% to 25% of all pregnancies. I Yet there are still major disagreements as to when intervention for delivery should occur and whether antibiotics, steroids, or tocolytic agents should be used. I·' There is one outcome that occurs occasionally, which could have important implications in management. That is preterm prepartal rupture of the membranes with subsequent cessation of leakage of fluid and continuation of the pregnancy. We designate such patients as having had rupture of the membranes that "reseal," although other mechanisms could account for the discontinuation of vaginal amniotic fluid loss and remain to be evaluated. To our knowledge, the characteristics . and prognosis of cases that "reseal" have not been described in detail. Information concerning these patients could prove useful in selecting the best management for preterm prepartal rupture of the membranes and might provide insight into the cause. The purpose of this study was to determine in our patient population the frequency of such cases, their epidemiologic features, their obstetric characteristics (including amniotic fluid volumes as assessed by ultrasonographic studies), and their clinical course. From the Department of Obstetrics and Gynecology, College of Medicine, and the Department of Statistics, University of Florida. Presented as Official Guest at the Fifty-second Annual Meeting of the South Atlantic Association of Obstetricians and Gynecologists. Palm Beach. Florida. january 28-31, 1990. Reprint requests: john W. C. johnson, MD, Box ]-294, jHMHC, University of Florida College of Medicine, Gainesville, FL
32610.
6/6/22148
1024
Material and methods This case-control study was performed in patients giving birth at Shands Hospital during the years 1984 and 1985. There were 24 study cases with a diagnosis of preterm prepartal rupture of the membranes that subsequently "resealed" with continuation of the pregnancy (study group). Twenty-four women who had preterm prepartal rupture of the membranes but did not "reseal" (control group) were matched to the study group with regard to gestational age at the time of rupture and approximate calendar month of rupture. Data were abstracted from the medical records and included: (1) demographic factors, vital statistics, and socioeconomic indicators; (2) details of past obstetric performance; and (3) characteristics and outcomes of the current pregnancy. All 24 of the study cases and the 24 control cases were singleton pregnancies. Therefore data concerning multiple gestations were excluded from these analyses. The duration of pregnancy was assigned on the basis of the best estimate derived from menstrual data, early maternal physical examination, early ultrasonographic findings, and the infant's physical and neurologic development. The diagnosis of pre term prepartal rupture of the membranes was based on the history of sudden onset and continued vaginal leakage of fluid, which was confirmed by examination and positive ferning or alkaline testing with Nitrazine paper.' Patients with a diagnosis of prepartal rupture of the membranes were routinely hospitalized. In these patients the diagnosis of "resealing" was determined by daily inquiry of cessation of vaginal loss of fluid and by findings on speculum examination of absence of leakage and negative ferning or Nitrazine testing. Patients
Volume 163 Number 3
with a diagnosis of "resealed" were discharged to outpatient care. Ultrasonographic studies were performed routinely on most patients with suspected preterm prepartal rupture of the membranes at the time of admission with an ADR model 4000 scanner (Advanced Technology Laboratories, Inc., Bothell, Wash.) that used standard 3.5 or 5 MHz linear transducers. Amniotic fluid volumes were quantitated according to a previously described method" An obvious but slight decrease was designated as "one arrow down." If there was fluid behind the fetal back, but the largest vertical pocket measured 3 to 5 cm, the interpretation was a moderate decrease in amniotic fluid volume, designated as "two arrows down." If there was no fluid behind the fetal back and the largest vertical pocket measured only I to 3 cm, the interpretation was a marked decrease, designated as "three arrows down." The most severe decrease in amniotic fluid (oligohydramnios) was diagnosed if there was no fluid behind the fetal back and the largest vertical pocket was less than I cm in depth. This was designated as "four arrows down." Cervical or vaginal cultures for gonorrhea and group B streptococci were obtained on admission. In the event that either culture proved positive, appropriate antibiotic therapy was instituted. Otherwise, and in the absence of choreoamnionitis, antibiotics were not administered. As a general routine during 1984 and 1985, patients with preterm prepartal rupture of the membranes were not treated with tocolytic agents or steroids. Group comparisons were made with regard to maternal age, past obstetric peformance, race, level of maternal education, marital status, and history of substance abuse. Comparisons were also made between the two groups with regard to: (1) admission characteristics including maternal habitus expressed as weight-toheight ratio, hematocrit, white blood cell count, and ultrasound estimates of amniotic fluid volumes and (2) outcome variables including length of gestation at delivery, fetal birth weight, fetal sex, Apgar scores, perinatal outcome including mortality and neonatal morbidity, and duration of maternal and neonatal hospital stays. All statistical analyses were carried out by means of the Statistical Analysis Systems,S a computer software system for data analysis. For the continuous variables of interest a t test was performed to detect significant differences between the case and control group means. For nominal variables a X2 test was performed to test the independence of the outcome variable ("reseal") with the variables of interest. The Wilcoxon ranksum test was performed for the ordinal response variables. Kendall's tau b test was used for significant linear associations. Since several tests were performed and
Cases with ruptured membranes that "reseal"
1025
Table I. Gestational age at onset of rupture Preterm prepartal rupture of membrane, 1984-1985 Gestational age at membrane rupture (wh)
(n
