Sir.—A delay in pulmonary maturity and immature fetal lung profiles in infants born at term have been described in diabetic pregnancies.1 This case report and review of neonatal screening results show that a markedly immature lecithinsphingomyelin (L-S) ratio at term may be a prenatal marker for congenital hypothyroidism.
Petient Reports.—Patient 1.—A 25-year-old gravida 2 woman with normal glucose screen results was admitted at 32 weeks' gestation with a diagnosis of a bleeding placenta previa. The bleeding resolved, and beginning at 35 weeks, weekly amniocentesis was performed for fetal lung profiles to ascertain pulmonary maturity as outlined by Kulovich et al.2 The amniotic fluid L-S ratio never exceeded one and phosphatidyl glycerol was never detected. In spite of this, the infant was electively delivered at 40.5 weeks. The infant developed respiratory distress syndrome (RDS), which required intubation and mild ventilatory support. The thyrotropin level was 718