Randomized investigation of magnesium sulfate for prevention of preterm birth

Am J Obstet Gynecol. 1990 Sep;163(3):767-72. doi: 10.1016/0002-9378(90)91065-k.


One hundred fifty-six women with preterm labor between 24 and 34 weeks' gestation were randomized to receive either intravenous magnesium sulfate or no tocolytic therapy. Magnesuim sulfate infusions of up to 3 gm/hr were used in 76 pregnancies and resulted in a mean serum magnesium concentration of 5.5 +/- 1.4 mEq/L (mean +/- SEM). Compared with 80 control pregnancies, magnesium sulfate tocolysis had no significant effect on duration of gestation, birth weight, neonatal morbidity, and perinatal mortality. We conclude that clinically safe infusions of magnesium sulfate are ineffective when used to prevent preterm birth.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Female
  • Fetal Death / etiology
  • Humans
  • Magnesium Sulfate / adverse effects
  • Magnesium Sulfate / therapeutic use*
  • Obstetric Labor, Premature / prevention & control*
  • Pregnancy
  • Pregnancy Outcome
  • Randomized Controlled Trials as Topic


  • Magnesium Sulfate