Antenatal glucocorticoids (AG) for the prevention of respiratory distress syndrome in VLBW infants reduce the incidence of patent ductus arteriosus, intraventricular hemorrhage and necrotizing enterocolitis. In preterm fetal lambs, AG increase postnatal cardiac output (CO), heart rate (HR) and blood pressure (BP). We hypothesized that AG improve hemodynamic maturation in preterm infants. Twenty infants (750-1250 g; 24-31 wk) were enrolled in a prospective observational study. We measured middle cerebral (C) and superior mesenteric (M) artery Doppler blood flow velocities (BFV) and cardiac function at 6, 30, 54 and 168 hr of life. Infants were divided into three groups: non-treated controls (n=6), one dose (n=4), and two or more doses (n=10) of AG. Mean and end-diastolic CBFV increased (ANOVA, p<0.0001) by 83 and 230%, respectively, from 6 to 168 hr of age. Cerebral relative vascular resistance(RVR) decreased (ANOVA, p<0.05) by 27%. Mean MBFV and MRVR did not change, but end-diastolic MBFV increased (ANOVA, p<0.05) by 47%. HR, BP, and CO (fig.) increased (ANOVA, p<0.001) by 7, 35, and 60%, respectively. Contractility did not change. Mean and end-diastolic CBFV, mean and end-diastolic MBFV, CRVR, MRVR, HR, BP, CO and contractility did not differ among groups. We conclude that AG do not alter Doppler ultrasound indices of postnatal hemodynamic maturation in VLBW infants. Funded by Wyeth Pediatrics.

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