Magnesium Sulfate Versus Placebo for Tocolysis in Preterm Premature Rupture of Membranes

The majority of studies of the effectiveness of tocolysis with PPROM were in the 1980s prior to the commmon usage of antenatal steroids and prophylactic maternal antibiotics. In most studies, tocolysis was not attempted prior to the onset of labor in this group of women. The ACOG Practice Bulletin of June 1998 concedes that the recommendation of tocolysis to permit administration of steroids and maternal antibiotics is based primarily upon consensus, not consistent scientific evidence.

The purpose of this study, which will randomize 128 subjects to tocolysis or no tocolysis, is to prospectively assess whether short term (48 hr) tocolysis affords benefit to women and babies between 26 and 32 weeks gestation with PPROM.

Subjects will be enrolled at 1-2 high risk hospitals in Chattanooga and Knoxville. All English and Spanish speaking women 18-45 years with PPROM and cervical dilation <4 will be eligible. Women with suspected intrauterine infection, positive fetal lung maturity, or > 6 hours tocolysis at time of admission will be excluded.

Both groups of women will receive continuous fetal monitoring, antibiotics, and antenatal steroids (if not previously administered). Both groups will be evaluated every 2-4 hours for fetal and maternal well being. Both groups will receive IVF at 125cc/hr, and the treatment group will be loaded with 4 grams of magnesium sulfate and receive maintainence dose of 2 grams/hr x 48 hrs.