Full-term-pregnancy effects of antenatal betamethasone administration on short-term variation as assessed by...

to verify whether there are other than transitory effects of antenatal betamethasone (administered for fetal lung maturity [FLM] enhancement) on fetal heart rate (FHR) variability detected by computerized cardiotocography (cCTG) in cases where formerly steroid-treated fetuses reached term.

cCTG of one hundred sixty-four women (study group) exposed to antenatal betamethasone for risk of preterm delivery in third trimester period were compared to controls (pregnancies who presented risk of preterm labour in the same period of cases, although with no steroids administration). cCTG was performed weekly as of standard schedule when pregnancies reach term from 37-40 weeks' gestation for cases and controls.

regarding data concerning cCTG at term for cases and controls, no significant difference was found for FHR, Acc (accelerations) 10 min, and FM (fetal movements) between groups. LV (low variation)/min and LV/msec were absent in cCTG parameters of fetuses in the study group. Instead, for all weeks studied (37 to 40), cCTG parameters were higher for HV (high variation)/msec, STV(short term variation)/msec, and Acc 15 in cases with respect to controls.

interestingly, maternal corticosteroid administration may be related to higher fetal reactivity when fetuses exposed to steroid therapy reach term. Our observation may help in the interpretation of a "more reactive" CTG trace in babies whose mothers previously received steroid therapy for FLM enhancement.