RENO, NEV. — A single course of prenatal steroids given to hasten fetal lung maturity is effective for longer than 7 days, meaning there may be no need for a repeat, rescue dose, Alan M. Peaceman, M.D., said at the annual meeting of the Society for Maternal-Fetal Medicine.
In a review of 162 infants whose mothers had received a single, full course of prenatal steroids and who were born before 34 weeks' gestation, the only significant difference between those born within 7 days of the treatment and those born after 7 days was a greater need for ventilatory support.
“I think we need to reexamine our assumption that steroids lose their benefit after 7 days,” he said in an interview.
In 2000 a National Institutes of Health consensus panel recommended against the practice of repeat courses of prenatal steroids when a patient at risk for premature delivery did not deliver within 7 days of the treatment because of the possible risks associated with multiple courses.
It is not uncommon, however, for some physicians to use a single, repeat “rescue” course when delivery seems imminent and 7 days have elapsed, or for physicians to hold off giving the initial course until just before they think the patient will deliver, said Dr. Peaceman of the department of maternal-fetal medicine at Northwestern University, Chicago.
The evidence offered by his review of cases is not as definitive as that of a prospective trial, he said, but it does suggest one could give a single course at 24 weeks, as guidelines suggest.
“I'm not recommending anything,” Dr. Peaceman said in the interview. “But that is what the data are leaning toward: That there is no point in waiting” until closer to a patient's expected delivery date. Similarly, there is no need to give a repeat or “rescue” dose after 7 days if the patient still has not delivered.
In the reviewed cases, 84 of the 162 infants were born within 7 days of the treatment and 78 were delivered after 7 days. The groups did not differ in any of the assessed characteristics, including maternal age, route of delivery, and birth weight, Dr. Peaceman and coinvestigator William A. Grobman, M.D., also of the department, wrote in a poster that was presented at the meeting.
Respiratory support, defined as mechanical ventilation or continuous positive airway pressure use for greater than 24 hours, was needed by 63% of the infants delivered within 7 days, compared with 81% of the infants delivered after longer than 7 days.
None of the other outcomes considered, however, showed any statistically significant difference between groups. (See table.)
In a subanalysis, the researchers assessed data for those infants born at less then 30 weeks' gestation. There were still no significant differences between treatment groups other than respiratory support. Furthermore, the study observed no association between neonatal morbidity and the length of time beyond 7 days that passed before delivery.