Induction of labor with a Foley catheter and the risk of subsequent preterm birth: A follow-up study of two randomized controlled trials (PROBAAT-1 and -2)

M D T de Vaan* (Corresponding Author), D Blel, K W M Bloemenkamp, M Jozwiak, M L G Ten Eikelder, J W de Leeuw, M A Oudijk, J J H Bakker, R J P Rijnders, D N Papatsonis, M Woiski, B W Mol, R de Heus

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


OBJECTIVE: The objective of this study was to evaluate the preterm birth rate in a subsequent pregnancy in women who had undergone term induction with a Foley catheter in comparison to induction with prostaglandins.

METHODS: This was a follow-up study of two large randomized controlled trials. In the original trials (PROBAAT-1 and PROBAAT-2), women with a term, singleton pregnancy in cephalic presentation with an indication for labor induction were randomized to either a 30cc Foley catheter or prostaglandins (i.e. vaginal prostaglandin E2 in PROBAAT 1 and oral misoprostol in PROBAAT 2). The main outcome measures were preterm birth <37 weeks gestation and preterm birth <34 weeks gestation. Data were collected from hospital charts on subsequent pregnancies from hospitals participating in this follow-up study.

RESULTS: 14 hospitals agreed to participate in this follow-up study. Of the 1142 eligible women, 162 women (14%) were lost to follow-up. Of the 572 women randomized to a Foley catheter, 251 women had a subsequent pregnancy beyond 16 weeks gestation, versus 258 women of the 570 women who received prostaglandins. There were no differences in baseline characteristics. The overall preterm birth rate was 9/251 (3.6%) in the Foley catheter group versus 10/258 (3.9%) in the prostaglandin group (RR 0.93; 95%CI 0.38-2.24), with spontaneous preterm birth rates of 5/251 (2.0%) versus 5/258 (1.9%) respectively (RR 1.03, 95%CI 0.30-3.51).

CONCLUSIONS: In women with a singleton term pregnancy, induction of labor with a 30cc Foley catheter is not associated with an increased risk of preterm birth in a subsequent pregnancy as compared to induction of labor with prostaglandins. This article is protected by copyright. All rights reserved.

Original languageEnglish
Number of pages26
JournalUltrasound in Obstetrics and Gynecology
Early online date17 Sep 2020
Publication statusE-pub ahead of print - 17 Sep 2020


  • Induction of labor
  • cervical ripening
  • Foley catheter
  • Balloon induction
  • preterm birth

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