Administration of steroids after 34 weeks of gestation enhances fetal lung maturity profiles

OBJECTIVE: To estimate 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. STUDY DESIGN: Pregnancies between 34(0/7) and 36(6/7) weeks undergoing amniocentesis to determine fetal lung maturity were targeted. Women with negative results (TDx-FLM-II <45 mg/g) were randomly assigned to intramuscular glucocorticoid injection or no treatment. A repeat TDx-FLM-II test was obtained 1 week after enrollment. RESULTS: Thirty-two women who met inclusion criteria were randomly assigned. Seven women delivered within a week of testing for fetal lung maturity, and were excluded from the analysis. Ten received glucocorticoid and 15 did not. Women assigned to glucocorticoids had a mean increase TDx-FLM-II in 1 week of 28.37 mg/g. Women assigned to no-treatment had an increase of 9.76 mg/g (P < .002). CONCLUSION: A single course of intramuscular glucocorticoids after 34 weeks in pregnancies with documented fetal lung immaturity significantly increases TDx-FLM-II.