Effectiveness and safety of the oxytocin antagonist( atosiban) versus beta-adrenergic agonists (salbutamol) in the treatment of preterm labor

Abstract

Background and Objectives: preterm labor complicates 5-10% of pregnancies and is a leading cause of neonatal morbidity and mortality worldwide and 70-80% of perinatal deaths occur in preterm infants. The aim of this study is to compare the effectiveness, safety and adverse effects of the oxytocin antagonist medication(atosiban) with those of beta-adrenergic agonist (salbutamol) in the treatment of patients with preterm labor.
Patients and Methods: one hundred pregnant women with preterm labor were enrolled in this study from the period of( January 2014 – January 2015) at Al-Diwaniya Maternity and Pediatrics Teaching Hospital-Iraq with a gestational age of 24-34 weeks, they were randomly assigned to receive tocolytics either salbutamol (n=50) or atosiban (n=50).Salbutamol was given by(intravenous infusion 10-50 microgram)for up to 48 hour. Atosiban was given by (intravenous bolus dose of 6.75 mg then 300microgram/minute for 3 hour and 100microgram/minute for up to 48hour). Retreatment with the study drugs or alternative tocolytic agents was allowed. Main outcome measures included were tocolytic effectiveness, which was assessed in terms of number of women undelivered after 48hour and 7 days. Tocolytic safety was assessed in terms of maternal and fetal side effects and neonatal morbidity.
Results: there were no significant differences between the salbutamol and the atosiban group in prolongation of pregnancy for 48 hour (44% versus 46%;p=0841)and 7 days(20% versus 32%;p=0.171) ,respectively. Maternal adverse events , including tachycardia occurred more frequently in the salbutamol group(22% versus 8%;p=0.050).Neonatal outcomes and complications were comparable between the two study groups(42% versus 32%;p=0.30).
Conclusions: the oxytocin antagonist (atosiban) was as effective as beta-agonist(salbutamol) in delaying threatened preterm birth , and found to be better tolerated by both the mother and fetus than salbutamol , with a comparable neonatal safety profil.This study supports the clinical use of atosiban as a first line tocolytic in the treatment of preterm labor.