Prolonged PROM, labor induction, and cesareans
Women who undergo induction of labor after prolonged premature rupture of membranes (PROM) at term are more likely to need a cesarean delivery than their counterparts whose labor begins spontaneously 24 hours within 24 hours of PROM. However, they are not at increased risk for other labor complications or any adverse neonatal outcome, according to the results of a recently published retrospective cohort study.
The investigation included data from 625 deliveries at the Helen Schneider Hospital for Women, Rabin Medical Center, Tel Aviv, Israel. Of the women in the study population, 155 had induction of labor after 24 hours since PROM, and 470 experienced spontaneous onset of labor within 24 hours after PROM. The 2 groups of women were similar with respect to maternal age, parity, and obstetrical complications.
Between group comparisons for various maternal outcomes showed that the rate of cesarean delivery was more than 2-fold higher among women who had labor induced compared with the group having spontaneous onset of labor (13.5% vs 6.0%; P = .005); in a multivariable logistic regression analysis, prolonged PROM was associated with a statistically significant, 8.27-fold increased risk of cesarean delivery (P = 0.025). Analyses of the indications for cesarean delivery showed that the rate of labor dystocia was significantly higher in the induction group than in woman having spontaneous onset of labor (6.5% vs 2.3%; P= .02).
There were no statistically significant differences between the 2 groups of women in the rates of intra- or postpartum fever, postpartum hemorrhage or need for blood products nor when comparing them for neonatal outcomes, including birthweight or rates of neonatal intensive care unit admission, sepsis, intubation, or other short term neonatal morbidities. There were also no neonatal deaths in the series.
“Previous studies evaluating management of women presenting with PROM at term demonstrate that compared with expectant management, immediate induction of labor is associated with better outcomes in terms of faster time to delivery, a lower rate of endometritis, and higher patient satisfaction, but without significant neonatal adverse outcome. Thus, practice guidelines for PROM at term mainly indicate immediate induction with oxytocin,” said Dr Eyal Krispin, physician in the Feto-Maternal ward at the Helen Schneider Hospital for Women, Rabin Medical Center, Tel Aviv, Israel.
“Our study has the limitations of being retrospective in nature, and so its findings cannot be used to imply different guidelines for management of PROM at term. Still, it provides additional support for counseling women that they are not exposing their baby to risk if they choose expectant management, but that they may have a greater chance of needing cesarean section.”
Dr Krispin and colleagues were interested in evaluating perinatal outcomes in women presenting at their center with PROM considering it is not infrequent—according to various studies, its prevalence is 8% to 10%. In addition, immediate induction is not an option at all medical centers, and even when it is, expectant management is preferred by a significant proportion of patients.
The women included in their retrospective study were identified from among all those who delivered at the tertiary medical center in 2013 to 2014. Eligibility criteria required rupture of membranes from 37 +0 to 41 + 6 weeks of gestation and a Bishop score ≤7 at presentation. According to the center’s protocol, women in active labor and those with a Bishop score >7 receive immediate oxytocin labor augmentation. Women with intrauterine infection (amnionitis), placental abruption, or fetal compromise are also considered for immediate delivery. Women with multiple gestations, a history of cesarean delivery, or any features of a complicated pregnancy were excluded from the study population.
At the Helen Schneider Hospital for Women, monitoring during expectant management of women with PROM at term includes temperature measurements and cardiotocogram every 8 hours plus a daily white blood cell differential count to rule out amnionitis. After 24 hours, labor is induced with intravaginal insertion of slow-release prostaglandin E2 10 mg. The vaginal insert is kept in place for up to 24 hours, but removed sooner if the Bishop score is >7 or upon development of painful uterine contractions, uterine hyperstimulation, or fetal distress.
“Another limitation of our study is that it provides no information about labor induction with oxytocin. The ideal method of labor induction in women with PROM at term and a low Bishop score warrants future prospective study,” Dr Krispin said.