Revisiting amniocentesis for fetal lung maturity after 36 weeks' gestation.

Respiratory distress syndrome (RDS) remains a major cause of perinatal morbidity and mortality in premature infants. To avoid iatrogenic RDS, The American College of Obstetricians and Gynecologists (ACOG) recommends that obstetricians confirm fetal pulmonary maturity prior to elective delivery less than 39 weeks' gestation. However, ACOG based such recommendations primarily on studies carried out prior to the routine use of antenatal corticosteroids to accelerate lung maturity and the liberal use of ultrasound to confirm gestational age. Recent studies suggest that testing for fetal lung maturity at more advanced gestational ages is neither reliable nor cost effective. This article reviews the current literature on the use of amniocentesis to confirm fetal lung maturity prior to elective delivery at 36 to 39 weeks' gestation.