DOES MAGNESIUM-SULFATE GIVEN FOR PREVENTION OF ECLAMPSIA AFFECT THE OUTCOME OF LABOR

OBJECTIVE: The purpose of this study was to determine whether magnesiu m sulfate given for prevention of eclampsia affected labor outcomes co mpared with phenytoin, which is not known to impede uterine activity w hen given in anticonvulsant doses. STUDY DESIGN: Secondary analysis wa s performed of a study of women with pregnancy-induced hypertension wh o were admitted for delivery and randomly assigned to receive either m agnesium sulfate or phenytoin for eclampsia prophylaxis. Nulliparous w omen with a singleton pregnancy in cephalic presentation at term were selected for analysis in an effort to limit the influence of confoundi ng variables such as preterm birth and malpresentations on labor manag ement and outcomes. Similarly women who had severe preeclampsia and wh o received labor epidural analgesia were excluded. RESULTS: A total of 2138 women were randomized to receive magnesium sulfate or phenytoin in the primary study. A total of 905 nulliparous women met the inclusi on criteria for this secondary analysis; 480 had been randomized to ph enytoin and 425 were given magnesium sulfate. The two groups were simi lar demographically. Labor outcomes such as (1) oxytocin stimulation, (2) admission-to-delivery intervals, (3) prolonged second-stage labor, (4) forceps delivery, and (5) cesarean delivery were not affected by maternal treatment with magnesium sulfate. CONCLUSION: Compared with p henytoin, magnesium sulfate given for intrapartum treatment of pregnan cy induced hypertension does not significantly affect labor outcomes.