Repeated fetal betamethasone treatment and birth weight and head circumference

Objective: To assess the effect of repeated courses of betamethasone on birth weight and head circumference. Methods: We conducted a historical cohort study of inpatients receiving betamethasone therapy over 5 years. We compared birth weights and head circumferences of infants whose mothers received one course of betamethasone with those of infants whose mothers received multiple courses. Multiple regression analysis was used to adjust for potential confounding variables. Sufficient power (80%) existed to detect a 20% difference between the groups (alpha = 0.05). Results: Mean birth weights (+/-SD) were 1717 +/- 707 g in the single-course group (n = 107) and 1783 +/- 647 g in the multiple-course group (n = 45) (P =.59, Student t-test). Mean head circumference was 28.2 +/- 3.6 cm in the single-course group and 29.2 +/- 2.9 cm in the multiple-course group (P =.15, Student t-test). In regression analysis, birth weights (1757 g and 1752 g) and head circumferences (28.5 cm and 29.0 cm) did not differ significantly different between the single-course and multiple-course groups. Conclusion: Multiple courses of betamethasone do not reduce birth weight or head circumference in neonates compared with single-course therapy. (Obstet Gynecol 2001; 97:301-4. (C) 2001 by The American College of Obstetricians and Gynecologists.).