Effect of Social Vulnerability Index on Betamethasone Timing in Patients at Risk of Preterm Birth

Background/Objectives: Several social vulnerability index (SVI) components have been associated with adverse obstetrical outcomes and provider bias. The objective of this study is to assess whether betamethasone administration timing among patients at risk for preterm birth differs by social vulnerability index. Methods: A multicenter retrospective cohort study of pregnant people at a large academic healthcare system between January 2019 and January 2023. Patients with live singleton gestations at risk for preterm birth who received at least one dose of intramuscular betamethasone for fetal lung maturity from 22 to 34 weeks were included. Patients aged less than 18, who received late-preterm corticosteroids and/or had scheduled delivery at 34 weeks were excluded. We analyzed the association between patient SVI quartile and maternal demographic factors on betamethasone timing, with optimal timing defined as the receipt of two doses of betamethasone within 2 to 7 days of delivery. Results: 1686 patients met the inclusion criteria. Only 22.4% of patients had optimally timed betamethasone administration. Among those who did not receive optimal betamethasone timing, 360 patients delivered less than 48 h from the first dose and 948 delivered greater than 7 days from the first dose. Optimal betamethasone timing within 2 to 7 days of delivery was more common in patients with higher SVI values. Patients with lower social vulnerability were more likely to deliver greater than one week from betamethasone administration. Conclusions: Patients in higher SVI quartiles are more likely to have optimally timed betamethasone. This is likely attributed to overtreatment with betamethasone of less socially vulnerable populations.