Single vs Repeat Courses of Antenatal Corticosteroids in Women at Risk of Preterm Birth

Abstract

Background: Antenatal corticosteroids are an established intervention for women at risk of preterm birth. The role of repeat courses remains clinically important when substantial risk persists after an initial course.

Objective: To compare maternal and neonatal outcomes associated with single versus repeat courses of antenatal corticosteroids.

Materials and methods: This observational cohort study included 200 women at risk of preterm birth. Participants receiving a single course (n=100) were compared with those receiving repeat courses (n=100). Maternal, obstetric, treatment, and neonatal variables were analyzed. Crude associations were followed by multivariable logistic regression, penalized regression for sparse outcomes, propensity-score matching, and sensitivity analyses as reported in the study analysis.

Results: Repeat-course recipients had older maternal age, higher BMI, earlier gestational age at first course, longer interval to delivery, and substantially higher rates of preeclampsia, PPROM, and hypertension. Crude neonatal morbidity was higher in the repeat group. RDS occurred in 68% versus 8% (OR 24.3, 95% CI 8.5–69.4; p<0.001), while NICU stay was 34 versus 9 days. After adjustment, the RDS association attenuated to OR 2.1 (95% CI 0.8–5.4; p=0.14). Propensity matching likewise showed no statistically significant association.

Conclusion: Repeat corticosteroid courses were associated with substantially worse crude outcomes, but these associations markedly attenuated after adjustment for baseline risk, supporting substantial confounding by indication rather than an independently demonstrated adverse treatment effect.