The effect of membrane sweeping on prelabor rupture of membranes: a randomized controlled trial.

OBJECTIVE To estimate if membrane sweeping increases the rate of prelabor rupture of membranes. METHODS This randomized trial of term, uncomplicated pregnancies included 300 patients. Patients were randomly assigned into sweep or no-sweep groups, with patients and delivering providers blinded to group allocation. Only the examining provider in the clinic was unblinded to group allocation. Membranes were then swept or not swept at each weekly visit from 38 weeks of gestation onward, depending on the randomization. Data collected included parity, cervix examination at each visit, estimated gestational age at delivery, rupture of membranes, and maternal or fetal complications. RESULTS A total of 162 patients were randomly assigned to the membrane sweep group and 138 to the no-sweep group. There was no difference in baseline characteristics or obstetric and neonatal outcomes between the groups. The average gestational age at delivery and induction rate were not different. The overall prelabor rupture of membranes rate was not significantly higher in the membrane sweep group (12% compared with 7%) (P=.19); however, patients with a cervix more than 1 cm dilated at time of membrane sweeping were more likely to have prelabor rupture of membranes if they were in the membrane sweep group (9.1% compared with 0%; relative risk 1.10, 95% confidence interval 1.03-1.18). CONCLUSION No benefit in gestational age at delivery or reduction of postmaturity occurred from membrane sweeping. Although the overall prelabor rupture of membranes rates were similar, patients with membrane sweeping occurring at more than 1 cm cervical dilation may be at increased risk of prelabor rupture of membranes. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, www.clinicaltrials.gov, NCT00294242. LEVEL OF EVIDENCE I.