Efficacy of a single dose of antenatal corticosteroids on morbidity and mortality of preterm infants.

OBJECTIVE

To assess the effectiveness of an incomplete course of antenatal corticosteroids (ACS) on neonatal morbidity and mortality of preterm infants.

METHODS

Preterm infants born at 25-34 weeks' gestational age between January 1, 1998 and December 31, 2003 were included in this study. Studied infants were divided in two groups: the ACS group included those infants who had been exposed to a single 12-mg dose of betamethasone before delivery while the control group included those infants who had been delivered without any antenatal corticosteroids treatment. The most important neonatal outcomes were compared between the two groups.

RESULTS

One hundred and seventy neonates (41.4%) were exposed to one 12-mg dose of betamethasone before delivery, while 241 neonates (58.6%) did not receive any antenatal corticosteroids treatment. Mean gestational age at delivery (30.4+/-2.4 weeks versus 31.2+/-2.9 weeks, p=0.004) and mean birth weight (1375+/-454 g versus 1625+/-580 g, p<0.001) were lower in the ACS group. The univariate analysis showed that delivery room intubation and respiratory distress syndrome were more frequent in the ACS group and that the length of stay was also significantly longer in this group. No differences were found concerning survival, neonatal morbidity, need for and duration of mechanical ventilation and oxygen therapy. The incidence of major outcomes in survivors was also similar. Logistic regression adjusted for gestational age showed that the exposure to a single dose of betamethasone before delivery was not associated with a significant reduction in the rate of any neonatal outcome. We also compared the outcomes in function of gestational age subclasses. In the 25-27 weeks subgroup, delivery room intubation, surfactant treatment and patent ductus arteriosus (PDA) were less frequent in ACS infants; they had also shorter ventilation and oxygen duration. In the 30-31 weeks subgroup, ACS infants had a lower incidence of mechanical ventilation and a shorter duration of oxygen therapy. Finally, no differences were found in the 28-29 weeks subgroup and in the 32-34 weeks subgroup.

CONCLUSION

Effects of incomplete antenatal corticosteroids are variable: they give some benefits to infants of 25-27 weeks gestational age, fail to show any difference in outcomes in the 32-34 weeks subgroup and are doubtful between these extremes.