Patterns of use and optimal timing of antenatal corticosteroids in twin compared with singleton pregnancies

Introduction: Previous reports have shown that suboptimal antenatal corticosteroids administration occurs in most cases. However, as multifetal gestations were either excluded or constituted a small proportion of the participants in these studies, little is known about the patterns of use of antenatal corticosteroids in twin pregnancies. Material and methods: We reviewed the records of women who received antenatal corticosteroids and delivered between 24 ^0/7 and 34 ^6/7 weeks of gestation during 2015-2017 at 2 university hospitals. Optimal antenatal corticosteroids timing was defined as delivery ≥24 hours ≤7 days from the previous antenatal corticosteroids course. Results: Of 424 pregnancies, 307 (72.4%) were singleton and 117 were (27.6%) twin. For twin compared with singleton pregnancies, gestational age at initial antenatal corticosteroids administration was lower (P = 0.02), the proportion of deliveries within the optimal window of the initial antenatal corticosteroids course was lower (19.7% vs 33.2%, P = 0.001), and the proportion of women eligible for a rescue antenatal corticosteroids course was higher (58.1% vs 32.9%, P < 0.0001). However, despite similar rates of rescue antenatal corticosteroids administration (P = 0.64), the overall rate of delivery within any optimal window (either initial or rescue course) was lower in twin than singleton pregnancies (26.5% vs 42.3%, P = 0.004), and the antenatal corticosteroids-to-delivery interval was longer (median 6.9 vs 4.2 days, P = 0.0009). In multivariate analysis, optimal antenatal corticosteroids administration was negatively associated with twin pregnancy (P = 0.04) and preterm labor (P = 0.05), and positively associated with the presence of gestational hypertensive disorders (P = 0.03). Conclusions: Twin pregnancy is an independent risk factor for suboptimal antenatal corticosteroids administration. Directed efforts should be made to improve the utilization of antenatal corticosteroids in this vulnerable group of women.