Mid-Childhood Bone Mass After Exposure to Repeat Doses of Antenatal Glucocorticoids: A Randomized Trial

Treatment of women at risk for preterm birth with repeat doses of glucocorticoids reduces neonatal morbidity, but could have adverse effects on skeletal development. We assessed whether exposure to repeat antenatal betamethasone alters bone mass in children whose mothers participated in the Australasian Collaborative Trial of Repeat Doses of Corticosteroids.

Women were randomized to a single dose of betamethasone or placebo, ≥7 days after an initial course of glucocorticoids, repeated each week that they remained at risk for preterm birth at <32 weeks' gestation. In this follow-up study, children underwent whole-body dual-energy radiograph absorptiometry at 6 to 8 years' corrected age.

Of 212 eligible childhood survivors, 185 were studied (87%; 91 repeat betamethasone group; 94 placebo [single course] group). Children exposed to repeat antenatal betamethasone and those exposed to placebo had similar whole-body bone mineral content (median repeat betamethasone: 553 g, interquartile range: 442-712 g; placebo: 567 g, interquartile range: 447-750 g; geometric mean ratio: 0.99; 95% confidence interval: 0.94-1.03, P = .55) and bone area (median repeat betamethasone 832 cm², interquartile range: 693-963 cm²; placebo: 822 cm², interquartile range: 710-1020 cm²; geometric mean ratio: 0.99, 95% confidence interval: 0.92-1.07, P = .75).

Exposure to repeat doses of antenatal betamethasone compared with a single course of glucocorticoids does not alter bone mass in mid-childhood.