For full-term, low-risk, nulliparous patients, induction of labor with a Foley balloon alone or concurrent with prostaglandins (PGE) is associated with a significantly lower risk of adverse neonatal outcomes than with PGE alone, according to a study in the American Journal of Perinatology.
The length of labor and delivery was also the shortest with concurrent Foley-oxytocin.
“Many pregnant women undergo induction of labor in everyday clinical practice,” said primary author Maria Andrikopoulou, an assistant professor of maternal fetal medicine at Columbia University Irving Medical Center in New York City. “There is a wide variety or combination of methods that are used in cervical ripening; however, the safest and most efficacious method is not yet established.”
The current study was a secondary analysis of the ARRIVE trial: a randomized trial of induction versus expectant management, which was conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network.
“We aimed to compare different agents for cervical ripening, as well as combinations, to determine which one is associated with best outcomes for mothers and babies,” Andrikopoulou told Contemporary OB/GYNÒ.
Of the 6,106 participants comprising the ARRIVE trial, 38.9% met criteria for this analysis. Participants were excluded for preripening membrane rupture, abruption, chorioamnionitis, fetal demise or cervical dilation ≥3.5 cm.
Of the cohort for analysis, 52.4% had cervical ripening with PGE; 12.2% had Foley-PGE; 16.2% had Foley alone; and 19.1% had Foley-oxytocin.
The maternal composite outcome was similar for all 4 groups: 19.7% for PGE alone; 24.1% for Foley-PGE; 21.3% for Foley only; and 19.4% for Foley-oxytocin.
The neonatal composite outcome was attained significantly less often for those who received Foley-PGE or Foley alone: 2.4% and 3.6%, respectively.
Participants who received Foley-PGE or Foley-oxytocin also had a shorter labor and delivery stay compared with PGE: an adjusted mean difference of -1.97 hours and -5.92 hours, respectively.
“In our study, of the NICHD MFMU Network, we found that maternal outcomes were comparable between the 2 groups,” Andrikopoulou said. “It was surprising to find that, in this large low-risk prospectively ascertained group, the rate of cesarean deliveries was similar between the groups, regardless of the cervical ripening agent.”
The authors also were surprised that neonatal outcomes differed between the different ripening methods. “Implications on the neonate deserves further study,” Andrikopoulou said.
Given the increasing incidence of induction of labor, “our analysis provides useful information on methods of induction in low-risk women,” Andrikopoulou said. “Still, one of the limitations of the study is that this is a secondary analysis of a randomized trial. Because of the observational nature of the analysis, our findings should be considered more hypothesis-generating.”
In addition, because only low-risk nulliparous women were included in the analysis, “our results are generalizable only to this cohort of women,” Andrikopoulou said.
Moreover, participants were not randomly assigned to the type of cervical ripening that they received, but rather to the type of cervical ripening method used per the discretion of the attending physician. “Therefore, randomized trials are needed to validate our results,” Andrikopoulou said.
Andrikopoulou reports no relevant financial disclosures.
Andrikopoulou M, Bushman ET, Rice MM, et al. Maternal and neonatal outcomes in nulliparous participants undergoing labor induction by cervical ripening method. Am J Perinatol. Published online August 5, 2021. doi:10.1055/s-0041-1732379