2326 The Journal of Maternal-Fetal and Neonatal Medicine, 2012; 25(11): 2326–2329 © 2012 Informa UK, Ltd. ISSN 1476-7058 print/ISSN 1476-4954 online DOI: 10.3109/14767058.2012.695819 Objective: To evaluate the impact of early vs. late amniotomy on delivery mode in women undergoing induction of labor. Study design: 143 women admitted for induction were random- ized to early amniotomy (EA, concomitant with the beginning of oxytocin infusion; n = 71) or to late amniotomy (LA, four hours after the beginning of oxytocin; n = 72). Randomization was stratified by parity. The primary outcome was the rate of cesarean. Secondary outcomes were duration of labor and intra- partum fever. Results: The cesarean rate was similar between groups (18% vs. 17% among nulliparous; and 3% vs. 0% among parous women, in EA and LA group, respectively). However, EA was associated with shorter oxytocin-to-delivery interval (12 vs. 15 h) and a non-significant decrease in intrapartum fever (3% vs. 25%) than LA in nulliparous women (p = 0.05). Conclusion: For women undergoing oxytocin induction, early amniotomy is associated with shorter labor in nulliparous women with no effect on the risk of cesarean section in both nulliparous and multiparous women. Keywords: Amniotomy, induction, labor Introduction Induction of labour is one of the most common obstetric proce- dures [1]. Induction of labour is performed for many maternal or fetal indications when the beneits of childbirth outweigh the risks of prolonging the pregnancy. Rates of labour induction have been increasing over time, passing from 9.5% in 1990 to 20.2% in 2000 and 22.6% in 2006, based on a national register of birth certiicates in the United States [2]. Since elective labour induc- tion is gaining popularity and has been associated with improved neonatal outcomes in particular situations, the overall rate of induction will unlikely decrease in the near future [3,4]. On the other hand, labour induction is associated with a two to threefold increased risk of cesarean delivery and has contributed to the increase of cesarean rates over the last two decades [4,5]. Amniotomy is used during spontaneous labour or induc- tion of labour, with the objective of accelerating the process. he exact mechanism is unknown, but it has been shown that amniotomy promotes release of oxytocin and prostaglandins [6,7]. Amniotomy has been extensively studied in the context of spontaneous labour, but the available evidence does not allow clear recommendations regarding its use [8]. During induc- tion of labour, amniotomy is commonly used in combination with oxytocin infusion. However, there is a lack of data on both efectiveness and ideal timing of this procedure. We found two randomized studies that compared early versus late amniotomy in combination with oxytocin infusion [9,10]. Mercer et al. found that early amniotomy was associated with a shorter labour (13.3 vs. 17.8 h), but with an increased risk of chorioamnionitis (39.3% vs. 10.6%) in women with a 60-min increment in oxytocin infu- sion rate, but not in women with a 30-min increment [10]. Levy et al. found that in women undergoing cervical ripening with a Foley catheter, induction of labour by oxytocin preceded by early amniotomy resulted in a higher rate of cesarean delivery for dystocia [9]. Neither study stratiied for parity, a factor clearly associated with both length of labour and cesarean rate. hese conlicting results leave uncertainty regarding the optimal management of amniotomy in labour induction. he aim of this randomized controlled trial was to compare early vs. late amni- otomy in a population of women undergoing labour induction at term. Methods his randomized controlled trial was conducted from October 2006 to May 2010, in two academic perinatal centres in Montreal, Canada. he study protocol was approved by the Research Ethics Board of each hospital. Women admitted to hospital for labour induction were considered eligible if they met the following criteria: age ≥ 18 years, a term singleton fetus in a cephalic presentation, and intact amniotic membranes. Fetal heart rate status had to be normal. Exclusion criteria were: maternal infection with HIV, B or C hepatitis, maternal fever at admission, fetal growth restriction less than the third percentile, severe preeclampsia, prior cesarean, suspicion of spontaneous rupture of membranes; unfavourable cervix, deined by a Bishop score less than 6. Women who had received prostaglandins for cervical ripening or labour induction were also excluded. Women who had a cervical ripening with Foley catheter and who were not in labour were eligible. Ater written consent was obtained, a vaginal digital examination was done by the resident or the attending physician to conirm the feasibility of amniotomy. hen, if the woman was still eligible Early versus late amniotomy for labour induction: a randomized controlled trial Karine Gagnon-Gervais 1,2 , Emmanuel Bujold 3 , Marie-Hélène Iglesias 1 , Louise Duperron 1 , André Masse 2 , Marie-Hélène Mayrand 2 , Andrée Sansregret 1 , William Fraser 1 & François Audibert 1 1 Department of Obstetrics and Gynecology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Quebec, Canada, 2 Department of Obstetrics and Gynecology, CHUM St-Luc, Université de Montréal, Montreal, Quebec, Canada, and 3 Department of Obstetrics and Gynecology, Faculty of Medicine, Université Laval, Québec, Quebec, Canada Correspondence: François Audibert, Department of Obstetrics and Gynecology, CHU Sainte-Justine Research Center, Université de Montréal, 3175 Cote Ste-Catherine, Montreal, Quebec, H3T 1C5, Canada. Tel: +1-514-345-4931. Fax: +1-514-345-4648. E-mail: francois.audibert@umontreal.ca J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by Northeastern University on 01/21/14 For personal use only.