Intramuscular Fetal Corticosteroid Therapy: Short-Term Effects on the Fetus

Objective: The aim of the study was to assess the short-term effects of direct intramuscular (i.m.) corticosteroid therapy on fetal biophysical profile, baseline fetal heart rate and the nonstress test, which indicate the degree of fetal hypoxia. Method: We evaluated the effect of direct i.m. fetal single-dose dexamethasone (4 mg/kg) on the fetal biophysical profile 2 h before and 2–4 h after corticosteroid therapy in 41 fetuses in the 32nd week of gestation at risk of preterm delivery. Risk factors for preterm delivery included pregnancy-induced hypertension and preeclampsia. Result: There was a statistically significant difference between fetal breathing movements before and after corticosteroid therapy (p = 0.019; 95% confidence interval for difference –11.75, –1.12). No significant changes were observed between baseline fetal heart rate before and after corticosteroid therapy (p = 0.99; 95% confidence interval for difference –4.81, +4.81), biophysical profile before and after fetal corticosteroid therapy, p = 0.235 as well as the nonstress test before and after therapy (p = 0.564). Conclusion: Direct corticosteroid i.m. fetal therapy results in increasing profound short-term fetal breathing movements. There are no changes in baseline fetal heart rate, biophysical profile score, and nonstress test.