Indomethacin and corticosteroids: an additive constrictive effect on the fetal ductus arteriosus.

The objective of this paper is to study the possible additive effect of corticosteroids to the known effect of indomethacin on potency of the human ductus arteriosus. Systolic and diastolic blood flow of the fetal ductus arteriosus was measured by echo Doppler at 26-32 weeks of gestation. Four groups of patients were studied according to the treatment they have received: group A (exposure to indomethacin and betamethasone); group B (indomethacin alone); group C (betamethasone); and group D (controls). Children in whom ductal constriction was noted in utero were followed by repeat cardiac echo Doppler examinations at the age of 1 to 2 years. In group A (indomethacin and betamethasone) fetal ductal constriction was significantly higher (p = 0.02) and occurred in 11 out of 15 fetuses (73.3%), compared with 5 out of 14 (37.2%) of the fetuses in group B (indomethacin alone). In group C (betamethasone) and D fetuses (no treatment), no significant ductal constriction was observed. Pathological tricuspid regurgitation and right ventricular dilation were found more frequently in fetuses from group A. No long-term sequella was noted in the infants in whom ductal constriction had been noted in utero. Corticosteroids and indomethacin have a synergistic effect on the frequency and severity of fetal ductus arteriosus constriction. In short-term treatment this effect is transient, and has no deleterious effects on fetal and neonatal cardiac function.