Antenatal corticosteroid therapy and risk of osteoporosis

This is the authors' abstract. We don't add key points for this paper.

OBJECTIVE: To assess the risk of maternal osteoporosis associated with antenatal corticosteroid administration for neonatal respiratory distress syndrome prophylaxis. DESIGN: Prospective longitudinal study. SETTING: Maternity unit of Chelsea and Westminster Hospital, London. POPULATION: Fourteen pregnant women who received dexamethasone therapy for fetal lung maturation in anticipation of delivery before 34 completed weeks of gestation. METHODS: Blood samples were collected before dexamethasone administration, 24 hours and 48 hours after the course of dexamethasone, and within 24 hours of delivery. Serum levels of carboxy terminal pro-peptide of type I pro-collagen (PICP) were measured to monitor the rate of bone formation, and serum levels of cross-linked carboxy terminal telopeptide (ICTP) were measured as a marker of bone resorption. MAIN OUTCOME MEASURES: Changes in the markers of bone turnover following dexamethasone administration. RESULTS: Serum PICP levels dropped 24 hours after dexamethasone therapy (P = 0.001), but partially recovered by 48 hours (P = 0.014) to reach higher than pre-therapy levels at delivery (P = 0.044). Although there were no corresponding changes in the serum levels of ICTP after 24 and 48 hours of therapy, levels increased from pretherapy to delivery (P = 0.006). CONCLUSION: Antenatal corticosteroid therapy leads to a transient suppression of, followed by an increase in, bone formation without any significant alteration in the pattern of bone resorption expected during pregnancy.