Purpose. Our objective was to determine whether antenatal steroid administr
ation affects the biophysical profile score in fetuses.
Methods. A prospective study was conducted in 84 fetuses between 28 and 34
weeks' menstrual age at risk of preterm delivery. Two intramuscular injecti
ons of 12 mg of betamethasone were given to the mother 24 hours apart. All
fetuses underwent biophysical profile testing prior to and between 24 and 4
8 hours after steroid administration. Biophysical profiles (including nonst
ress tests) were evaluated by two maternal-fetal medicine specialists blind
ed to the timing of steroid administration. Neonatal outcome, including Apg
ar score, menstrual age at delivery, admission to and length of stay in the
neonatal intensive care unit, and mortality, was analyzed in all subjects.
Results. In 31 (37%; 95 confidence interval, 26.6-47.2%) of 84 cases, the b
iophysical profile score decreased at least 2 points after steroid administ
ration. The most commonly affected variables were fetal breathing and the n
onstress test. There was no significant difference in the neonatal outcome
between the fetuses whose biophysical profile decreased and those whose did
not.
Conclusions. Biophysical profile scores were decreased in more than one thi
rd of fetuses within 48 hours of antenatal steroid administration, but neon
atal outcome was not affected. Knowledge of this occurrence could avoid inc
orrect decision making regarding fetal well-being. (C) 2000 John Wiley & So
ns, Inc.