Ampicillin-metronidazole treatment in idiopathic preterm labour: a randomised controlled multicentre trial

Abstract

Objective: To determine whether treatment with ampicillin and metronidazole in women with threatened idiopathic preterm labour will prolong the gestation and reduce maternal and neonatal infectious morbidity.

Design: Randomised controlled double-blind trial.

Setting: Six obstetric departments in the Copenhagen area.

Population: One hundred and twelve women with singleton pregnancies, with threatened idiopathic preterm labour and intact amniotic membranes at 26 to 34 weeks of gestation.

Methods: Random allocation to eight days intravenous and oral treatment with ampicillin and metronidazole, or placebo.

Main outcome measures: Number of days from admission to delivery, gestational age at delivery, rates of preterm delivery, low birthweight, maternal infections and neonatal infections.

Results: Treatment with ampicillin and metronidazole was associated with a significant prolongation of pregnancy (admission to delivery 47.5 days versus 27 days, P < 0.05), higher gestational age at delivery (37 weeks versus 34 weeks, P < 0.05), decreased incidence of preterm birth (42% versus 65%, P < 0.05), and lower rate of admission to neonatal intensive care unit (40% versus 63%, P < 0.05), when compared with placebo treatment. Antibiotic treatment had no significant effects on infectious morbidity.

Conclusions: Treatment with ampicillin and metronidazole in women with threatened idiopathic preterm labour significantly prolonged the gestation, but had no effects on maternal and neonatal infectious morbidity.