The effect of betamethasone versus dexamethasone on fetal biophysical parameters

Background: Clinical observations suggest that betamethasone reduces matern al perception of fetal movements and short term variability, but that this dose not occur after treatment with dexamethasone. Objectives: To compare t he effect of betamethasone and dexamethasone on fetal biophysical parameter s. Methods: In a randomized, prospective, double blind study, 20 courses of betamethasone and 20 courses of dexamethasone were given in random sequenc e to patients with imminent preterm labor. During the first 32 h after init iation of treatment, fetal movements were counted by the mothers and record ed by ultrasound, and a nonstress test was performed. Results: Betamethason e induced a significant decrease in fetal movements as perceived by the mot her and observed by ultrasound. Fetal breathing movements also decreased. D examethasone did not change fetal body movements. Neither drug changed the short term variability. Conclusions: Unlike betamethasone, dexamethasone do es not induce a decrease in fetal movements. Dexamethasone might, therefore , be preferred for enhancement of lung maturation in imminent preterm labor . (C) 2001 Elsevier Science IreIand Ltd. All rights reserved.