Multicentre, parallel group, randomised, single-blind study of the safety and efficacy of atosiban versus ritodrine in the treatment of acute preterm labour in Korean women.
OBJECTIVE: To compare the efficacy and safety of atosiban with those of ritodrine in preterm labour. DESIGN: Multicentre, single-blind, randomised, controlled trial. SETTING: Obstetric units in six referral centres in Korea. POPULATION: Women with singleton pregnancies with preterm labour, between 24 and 33 + 6 weeks of gestation. METHODS: One hundred and twenty-eight women were randomised to receive intravenous atosiban (n= 63) or ritodrine (n= 65) and were stratified by gestational age (<28 weeks and >or=28 weeks). Atosiban or ritodrine was administered for up to 48 hours. Progression of labour was assessed by the frequency of contractions and cervical dilatation and effacement. Alternative tocolysis could be given as rescue therapy. MAIN OUTCOME MEASURE: Efficacy was assessed as the proportion of women in each group who did not deliver and did not need alternative tocolytic therapy at 48 hours and 7 days after therapy initiation. Safety was assessed as the numbers of maternal adverse events and neonatal morbidity. RESULTS: Tocolytic efficacy after 7 days was significantly better in the atosiban group than in the ritodrine group (60.3 versus 34.9%), but not at 48 hours (68.3 versus 58.7%). Maternal adverse events related to therapy were reported less frequently in the atosiban group (7.9 vs 70.8%; P= 0.0001), resulting in fewer early drug terminations due to adverse events (0 versus 20.0%; P= 0.0001). This, however, was not accompanied by a concurrent improvement in perinatal outcomes. CONCLUSION: The efficacy and safety of atosiban in the treatment of preterm labour were superior to those of ritodrine.