The effect of antenatal dexamethasone administration on the fetal and neonatal ductus arteriosus. A randomized double-blind study.

OBJECTIVE

To determine whether antenatal dexamethasone sodium phosphate administration constricts the fetal ductus arteriosus or improves spontaneous closure of the ductus in premature infants.

DESIGN

A randomized double-blind study.

SETTING

University hospital of Helsinki, Finland.

PARTICIPANTS

Sixty-one pregnant women with threatened preterm delivery between 24 and 31.9 weeks' gestation and 57 of their offspring (28 in the dexamethasone and 29 in the placebo group), born at 24 to 34.9 weeks' gestation, were studied using Doppler echocardiography.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between the dexamethasone and placebo groups, there were no significant differences in systolic or diastolic flow velocity values in the fetal ductus arteriosus. Of the 29 infants with respiratory distress syndrome, 26 (90%) had hemodynamically significant patent ductus arteriosus and received indomethacin sodium: 12 (92%) of 13 dexamethasone-treated infants and 14 (88%) of 16 placebo-treated infants. One placebo-treated infant was ligated. Of the 28 infants without respiratory distress syndrome, only four (14%) had hemodynamically significant patent ductus arteriosus. In infants born at or before 30 weeks' gestation, spontaneous closure of the ductus occurred more frequently after administration of prenatal dexamethasone (in six of 17 infants; 35%) than placebo (in none of 10 infants; P < .05).

CONCLUSIONS

Our data indicate that antenatal dexamethasone administration had no constrictive effect on the ductus arteriosus of the fetus between 24 and 31 weeks' gestation. However, antenatal dexamethasone had a beneficial effect on ductal closure in very premature infants.