Ritodrine versus salbutamol for external cephalic version

BACKGROUND: Treatment with beta-agonist tocolytics preceding external cephalic version (ECV) attempt increases success rates. Most studies have focused on intravenously and orally administered beta-agonists, while other administration routes including intramuscularly (IM) and subcutaneously (SC) are understudied. The aim of this study was to compare the efficacy of IM ritodrine to SC salbutamol given prior to ECV. METHODS: Aretrospective study of patients who underwent ECV between 1/2012 and 12/2019 at two medical centers. We compared patients undergoing ECV following IM ritodrine versus SCsalbutamol. We matched the two groups by parity and placental location. Maternal, pregnancy, ECV procedure and neonatal characteristics were compared. RESULTS: Overall, 601 women were included in each group. Median maternal age and amniotic fluid index (AFI) were lower in the Ritodrine group (27 vs. 32 years, P<0.001, 11 vs. 15 AFIcm, P<0.001, respectively). The median gestational age at ECV was higher in the Ritodrine group (380/7 vs. 370/7 weeks gestation). Success rate was higher in the Ritodrine group (71.7% vs. 63.8%, P=0.003). Vaginal delivery rate was higher in the Ritodrine group (70.7% vs. 60.1%, P<0.001). The number needed to treat to benefit was 10. In a multivariate analysis, Ritodrine was independently associated with higher ECV success rates as compared with Salbutamol (aOR2.1, 95%CI1.52-2.89). CONCLUSIONS: Intramuscular ritodrine significantly improved the success rate of ECV compared to SC salbutamol, and both drugs were safe and acceptable before ECV.