Membrane sweeping doesn't increase prelabor ruptures, with one exception

The overall rate of prelabor rupture of membranes in women with uncomplicated pregnancies was not significantly higher among those who received membrane sweeps, when compared to those who did not, researchers report in the June issue of Obstetrics and Gynecology.

Micah J. Hill, of the Triplex Army Medical Center in Honolulu, HI, and colleagues conducted a blinded, controlled study of 300 women with term, uncomplicated pregnancies. The women were randomly assigned into sweep or no-sweep groups, with membranes swept or not swept at each weekly visit from 38 weeks' gestation onward, depending on the assigned group. There was no difference in baseline characteristics or obstetric or neonatal outcomes between the groups.

The investigators found that membrane sweeping provided no benefit in gestational age at delivery or reduction of postmaturity. The overall prelabor rupture of membranes rates were similar (12% in the sweep group, compared with 7% in the no-sweep group), but patients who were more than 1 cm dilated and in the membrane sweeping group were at increased risk of prelabor rupture of membranes, the authors note (9.1% compared with 0%).

"The rational for performing membrane sweeping has been to reduce the number of postmature inductions. If postmature inductions are decreased at the cost of more inductions for prelabor rupture of membranes, this would defeat the ostensible benefit of the procedure," Hill and colleagues write. "We found no overall difference in prelabor rupture of membranes rates between those receiving membrane sweeping and those without membrane sweeping."

Hill MJ, McWilliams GR, Garcia-Sur D, et al. The effect of membrane sweeping on prelabor rupture of membranes: a randomized controlled trial. Obstet Gynecol. 2008;111:1313-1319.