The use of magnesium sulfate as the primary tocolytic agent to prevent premature delivery.

The efficacy of magnesium sulfate was evaluated as the primary tocolytic agent in the management of patients at risk for premature delivery. One hundred ninety-two patients determined to be 36 weeks' gestation or less were treated. One hundred seven patients (55.7%) received an additional oral beta-mimetic agent once labor was arrested. One hundred nineteen patients had intact membranes and 73 patients had ruptured membranes. Delay of delivery of 48 hours or longer was achieved in 70.6% of the patients with intact membranes and 60.2% of patients with ruptured membranes. Intervening obstetric complications, maternal morbidity, and neonatal septic and respiratory morbidity were increased in patients with ruptured membranes compared to patients with intact membranes. Magnesium sulfate is considered to be effective tocolytic agent having minimal adverse effects in managing patients at risk for premature delivery. Its use in patients with ruptured membranes, as with any tocolytic agent, remains controversial.