Use of a Foley catheter for labor induction in women with an unfavorable cervix at term resulted in a similar cesarean section rate to use of prostaglandin E2 gel for labor induction, but with fewer maternal and neonatal side effects, according to findings from an open-label randomized controlled trial involving more than 800 women.
Cesarean section, most often done for failure to progress during the first stage of labor, was performed in 23% of 411 women induced using a Foley catheter, and in 20% of 408 women induced using vaginal prostaglandin E2 gel (relative risk, 1.13), Dr. Marta Jozwiak of Groene Hart Hospital, Gouda, the Netherlands, and her colleagues from the PROBAAT Study Group reported online in the Oct. 25 issue of The Lancet.
The frequency of vaginal instrumental deliveries was similar in the two groups as well (11% and 13% in the Foley catheter and prostaglandin E2 groups, respectively), the investigators said (Lancet 2011 [doi:10.1016/S0140-6736(11)61484-0]).
Two serious maternal adverse events occurred, both in the prostaglandin group. These included one uterine perforation after insertion of an intrauterine pressure catheter and one uterine rupture during oxytocin augmentation, they said, noting that both neonates were born in good clinical condition, but were admitted to the neonatal ward with suspected infection.
Four minor maternal adverse events occurred, including three allergic reactions (in one woman in the Foley catheter group and in two women in the prostaglandin E2 group), and blood loss on a second insertion of the catheter in one woman. Also, the rate of suspected intrapartum infection was significantly lower in the Foley catheter group (1% vs. 3%).
As for neonatal adverse events, the rate of admissions to the neonatal ward was significantly higher in the prostaglandin E2 group (12% vs. 20%), Dr. Jozwiak and her associates said.
Patients in the PROBAAT trial included women beyond 37 weeks’ gestation with a singleton pregnancy in cephalic presentation, with intact membranes and an unfavorable cervix as defined by a Bishop score less than 6. The women were enrolled at 12 centers throughout the Netherlands between Feb. 10, 2009 and May 17, 2010, and all had an indication for labor induction, and had no prior cesarean sections.
The findings in regard to cesarean section rates when labor induction is performed using a Foley catheter vs. prostaglandin E2 were confirmed by a meta-analysis that included data from this study. The meta-analysis also demonstrated that Foley catheter induction was associated with reduced rates of hyperstimulation (odds ratio, 0.44) and postpartum hemorrhage (OR, 0.60), the investigators reported, noting that although the use of a Foley catheter for labor induction did not increase the vaginal delivery rate when compared with use of prostaglandin E2 as they had hypothesized, the findings nonetheless support the use of Foley catheters.
"After induction with a Foley catheter, the overall number of operative deliveries for suspected fetal distress was lower, fewer mothers were treated with intrapartum antibiotics, and significantly fewer neonates were admitted to the neonatal ward," they said, adding: "We therefore think that a Foley catheter should be considered for induction of labor in women with an unfavorable cervix at term."
Also, in light of the low cost and easy storage of Foley catheters, their use could be suitable for developing countries and low-resource settings, Dr. Jozwiak and her associates noted.
Future studies should compare the use of Foley catheters with other prostaglandin preparations such as prostaglandin E1 (misoprostol) which is becoming increasingly popular worldwide, and should evaluate the use of Foley catheters in women with a prior cesarean section, they suggested.
The study’s findings could have important implications for women with a prior cesarean section, said Dr. Jane E. Norman and Dr. Sarah Stock, of the MRC Centre for Reproductive Health and the Queen’s Medical Research Center at the University of Edinburgh.
In these women, induction with prostaglandins is associated with uterine rupture, they noted in an editorial accompanying the article, explaining that prostaglandins affect both cervical ripening and contractions simultaneously, whereas the ideal strategy for induction is likely administration of a cervical ripening agent before stimulation of contractions. This, they argue, would decrease the need for fetal monitoring during ripening and reduce the risk of uterine rupture (Lancet 2011 [doi:10.1016/S0140-6736(11)61581-X]).
"Although women with a previous cesarean section were excluded from Jozwiak and colleagues’ study, a Foley catheter could be the ideal induction agent in this situation and should be assessed further in randomized trials," they said, adding that if such trials are done, avoidance of maternal and neonatal mortality and morbidity should be included as primary outcome measures, as they are "arguably as important as speed and avoidance of cesarean section."