Neonatal outcomes in term pregnancies treated with antenatal corticosteroids for suspected pre-term labor

To evaluate the association between antenatal corticosteroid treatment and neonatal outcome when delivery occurs at term.

A retrospective cohort study of all women with singleton gestations who delivered at term (37 + 0 to 41 + 6 weeks) in a tertiary medical center (2012-2015). Women with diabetes, suspected fetal growth restriction, antepartum fetal death, and fetal structural or chromosomal anomalies were excluded. The cohort was divided according to prior preterm (24 + 0 to 33 + 6 weeks) antenatal corticosteroids treatment due to threatened preterm labor (study group), vs. no such treatment (control group). Primary outcome was birthweight at delivery. Secondary outcomes were composites neonatal adverse outcomes. Logistic regression analysis was utilized to adjust results for potential confounders.

Of 25,872 women who were included in the study, 722 (3%) were treated with antenatal corticosteroids. Women in the treatment group had higher rates of nulliparity compared to controls (43% vs. 38%, p = 0.002). Birth weight was significantly lower in the corticosteroid treatment group (3077 g vs. 3264 g, p = 0.001), with higher rates of small for gestational age (11% vs. 6%, p = 0.001). Multivariate analysis adjusting for parity and gestational age demonstrated that corticosteroid treatment was associated with lower birth weight (B = - 93 g, 95% CI - 123 to - 66, p = 0.001). Treatment was not found to be associated with adverse neonatal outcomes composites.

Antenatal corticosteroid treatment is associated with lower birth weight and higher rates of small for gestational age neonates among women who eventually deliver at term. However, it is not associated with short-term adverse neonatal outcomes.