Risks and Benefits of Antenatal Multidose Steroids

abstract & commentary

Synopsis: Multiple courses of antenatal steroids are associated with a significant decrease in the incidence of RDS, without an apparent increase in neonatal sepsis or abnormal fetal growth.

Source: Elimian A, et al. Obstet Gynecol 2000;95:34-36.

To determine the effectiveness of multiple doses of antenatal steroids as compared to a single course, Elimian and colleagues performed a retrospective study evaluating neonatal outcomes of infants with birthweights less than 1700 g. Ninety-three neonates were exposed to two or more courses of steroids, while 261 infants were delivered after a single course. Elimian et al used betamethasone, two 12-mg intramuscular doses 24 hours apart, repeating the treatment seven days later if the patient had not delivered. The mean gestational age was higher among neonates exposed to multiple courses (29.6 weeks vs 28.7 weeks) and their birthweights were also significantly greater (1252 g vs 1159 g). Infants exposed to multiple courses of antenatal steroids had a significantly lower rate of respiratory distress syndrome (RDS) (15% vs 41%) and surfactant use after delivery (43% vs 57%). After adjustment for confounding variables, multiple courses of steroids were associated with a significant 65% reduction in the incidence of RDS. No differences were observed in the rates of intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), patent ductus arteriosus (PDA), or neonatal sepsis. No differences were noted in neonatal birthweight percentile or head growth.

Elimian et al conclude that multiple courses of antenatal steroids are associated with a significant decrease in the incidence of RDS, without an apparent increase in neonatal sepsis or abnormal fetal growth.

Comment by Steven G. Gabbe, Md

For more than 25 years, obstetricians have been using antenatal steroids to reduce neonatal RDS. Many studies have shown that, in addition to reducing RDS, antenatal steroids decrease the risks of IVH and NEC. The original study by Liggins and Howie demonstrated that the effect of a single course of steroids lasted for seven days.1 In this country, many obstetricians repeat steroid treatment if the patient has not delivered within a week. To date, prospective studies have not demonstrated a significant benefit from this practice, and concerns have been raised about the effects of repeated doses of steroids on the mother and fetus. In this retrospective study, Elimian et al observed a significant reduction in RDS and the need for surfactant after birth in preterm infants delivered before 30 weeks gestation. These differences remained after adjusting for confounding variables. In a multicenter randomized trial of single vs. weekly antenatal corticosteroids, Guinn and colleagues did not demonstrate a significant difference in composite neonatal morbidity (severe RDS, bronchopulmonary dysplasia, severe IVH, sepsis, NEC, or neonatal death) in infants treated with steroids between 24-31 6/7 weeks gestation.2 It has been my practice to administer weekly steroids to patients who are at significant risk for preterm birth. Given the continued controversy, I will continue this while awaiting the results of further prospective randomized trials.

References

1. Liggins GC, Howie RN. Pediatrics 1972;50:515-525.

2. Guinn DA, et al. Am J Obstet Gynecol 2000;182:512.

In the retrospective trial conducted by Elimian et al, which of the following were reduced in neonates who had been exposed to multidose antenatal steroids?

a. IVH

b. NEC

c. PDA

d. RDS

e. Sepsis