Fetal and neonatal outcomes after term and preterm delivery following betamethasone administration

OBJECTIVE: To determine the effects of betamethasone on fetal growth and neonatal outcomes. METHODS: A retrospective cohort study was performed of deliveries that occurred at Charité University Hospital Berlin, Germany, between January 1996 and December 2008. The betamethasone group included women with preterm labor and symptomatic contractions, cervical insufficiency, preterm premature rupture of membranes, or vaginal bleeding. Women in the control group were matched for gestational age at time of delivery and had not received betamethasone. Fetal growth changes and neonatal anthropometry were compared. RESULTS: Among 1799 newborns in the betamethasone group and 42 240 in the control group, betamethasone was associated with significantly lower birth weight (154 g lower on average) after adjusting for confounders (e.g. hypertension, smoking, and maternal weight), sex, and gestational age at delivery (P<0.05). The higher the dose, the greater the difference in mean birth weight versus controls in births before 34(+0)weeks (≤16 mg -444 g; 24 mg -523 g; >24 mg -811 g), without a detectable improvement in neonatal morbidity or mortality. There was a dose-dependent decline in expected fetal weight gain as estimated by serial ultrasonography examinations 6-8 weeks after betamethasone administration (P<0.05). CONCLUSION: Betamethasone exposure reduces fetal weight gain in a dose-dependent manner without improving neonatal morbidity or mortality.