To determine the effect of antenatal glucocorticoid administration on fetal lung maturity in pregnancies with known fetal lung immaturity between the 34th and 37th weeks of gestation.
Pregnancies between 34 0/7-36 6/7 weeks undergoing amniocentesis to determine fetal lung maturity were targeted. Women with negative results (TDx-FLM-II < 45 mg/g) were randomized to intramuscular (IM) glucocorticoid injection (6 mg dexamethasone every 12 hours for 4 doses or 12 mg betamethasone every 24 hours for two doses) or no-treatment. A repeat TDx-FLM-II test was obtained one week after enrollment by either amniocentesis or directly at the time of delivery.
Over a five year period 32 women who met inclusion criteria were randomized. Seven women (3 in the steroid arm and 4 in the no steroid arm) delivered within a week of repeat testing for fetal lung maturity. Ten received IM glucocorticoid and 15 received no-treatment. Women assigned to glucocorticoids had a mean TDx-FLM-II increase in one week of 26.22 + 9.72 (95% CI 15.54-36.9). Women assigned to no treatment had an increase of 9.76 + 2.03 (95% CI 5.41-14.11). The differences between the two groups were statistically significant (p<0.002). Although the study was not powered to detect differences in neonatal outcome, there were two NICU admissions secondary to respiratory distress requiring intubation; both in the no treatment arm. There were no maternal complications.
A single course of IM glucocorticoids even after 34 weeks in pregnancies with documented lung immaturity can significantly increase the TDx-FLM-II in one week. Patients with negative fetal lung maturity parameters between the 34th-37th weeks can benefit from a single course of steroids. The data suggest a potential to decrease neonatal morbidity and warrants a larger study to assess neonatal outcome.
© 2008 Mosby, Inc. Published by Elsevier Inc. All rights reserved.