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

M. D.T. de Vaan*, 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

2 Citations (Scopus)
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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
Pages (from-to)292-297
Number of pages6
JournalUltrasound in Obstetrics and Gynecology
Issue number2
Early online date1 Feb 2021
Publication statusPublished - Feb 2021

Bibliographical note

We thank all the women who participated in the PROBAAT trials and all participating
institutions and their staff for their contribution to this follow-up study.

The original PROBAAT-2 trial was funded by FondsNutsOhra. For the PROBAAT-1 trial and this follow-up study, no funding was received. MV received a doctoral grant for teachers by the Netherlands Organisation for Scientific Research (023.011.051). BM is supported by a NHMRC Practitioner Fellowship (GNT1082548). Funding sources had no role in design, execution, analyses, interpretation, or decision to submit results.


  • balloon
  • cervical ripening
  • Foley catheter
  • induction of labor
  • preterm birth


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