Effect of single versus multiple courses of antenatal corticosteroids on maternal and neonatal outcome

OBJECTIVE: Treatment of pregnant mothers with a single course of antenatal corticosteroids significantly reduces neonatal mortality and morbidity. Mul tiple weekly courses are often given. However, the safety and efficacy of r epeated courses of antenatal corticosteroids have not been adequately studi ed. STUDY DESIGN: A retrospective study was performed for 609 mothers and their 713 infants who were treated with 1 to 12 courses of antenatal corticoster oids. Data for 369 singleton preterm infants born at less than or equal to 34 weeks' gestation, 210 multiple gestations, and 134 infants delivered at greater than or equal to 35 weeks' gestation were analyzed separately. RESULTS: The incidence of respiratory distress syndrome was 45% for single- course and 35% for multiple-course groups (P=.005; odds ratio, 0.44; 95% co nfidence interval, 0.25-0.79). The multiple-course group also had significa ntly less patent ductus arteriosus (20% vs 13%, P=.016). incidence of death before discharge and other neonatal morbidities were similar. The multiple -course group had a reduction of 0.46 +/- 0.19 cm in head circumference at birth (P=.013) when adjusted for gestational age and preeclampsia, The 2 gr oups had similar birth weights. Infants born at >35 weeks' gestation, multi ple-gestation infants, and infants who were born >7 days after the last cor ticosteroid dose had similar outcomes, regardless of the number of courses they received. Mothers treated with multiple courses compared with a single course had a significantly higher incidence of postpartum endometritis (P= .013), even though they had a lower incidence of prolonged rupture of membr anes (24% vs 33%, P=.06) and similar cesarean delivery rates. CONCLUSION: Exposure to multiple courses of antenatal corticosteroids compa red with a single course resulted in a significant reduction in the inciden ce of respiratory distress syndrome in singleton preterm infants delivered within a week of the last corticosteroid dose. This was associated with a r eduction in birth head circumference and an increased incidence of maternal endometritis. Whether the potential benefits of repeated therapy clearly o utweigh the risks will ultimately be determined in randomized prospective c ontrolled trials.