Atosiban does not improve neonatal outcomes in threatened preterm births between 30-34 weeks

1. Perinatal mortality and neonatal morbidity were comparable between the atosiban and placebo groups.

2. Maternal adverse events were similar among patients who received atosiban versus placebo.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Tocolytic medications are commonly used to delay preterm birth. Atosiban, an oxytocin receptor antagonist, is one such tocolytic used for threatened preterm labor. However, the effect of atosiban on improving neonatal outcomes remains unclear. This randomized controlled trial aimed to determine whether atosiban is superior to placebo in reducing morbidity in women with threatened preterm birth between 30+0 and 33+6 weeks of gestation. The primary outcome was a composite of perinatal mortality and neonatal morbidity, while key secondary outcome was the occurrence of adverse maternal events. According to study results, there was no significant difference in neonatal outcomes between atosiban and placebo. Although this study was well done, it was limited by a low event rate, which may decrease the ability to detect smaller differences between groups.

Click to read the study in The Lancet

Relevant Reading: Atosiban in individuals with previous implantation failure undergoing frozen blastocyst transfer: a randomized controlled trial

In-depth [randomized controlled trial]: Between Dec 4, 2017, and Jul 24, 2023, 1270 patients were assessed for eligibility across 26 hospitals in the Netherlands, England, and Ireland. Included were patients ≥ 18 years with singleton or twin pregnancies experiencing threatened preterm birth between 30+0 and 33+6 weeks of gestation. Altogether, 752 patients (375 in atosiban and 377 in placebo) were included in the final analysis. The primary outcome of perinatal mortality and neonatal morbidity was similar in both groups (8% atosiban vs. 9% placebo, relative risk [RR] 0.90, 95% confidence interval [CI] 0.58-1.40). The secondary outcome of maternal adverse events showed no meaningful differences between the treatment and placebo groups (1% mortality in both, RR 0.73, 95% CI 0.16-0.23). Findings from this study suggest that atosiban does not improve neonatal outcomes and should not be used for threatened preterm birth.

Image: PD

©2025 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.