Prevalence and etiology of respiratory distress in infants of diabetic mothers: predictive value of fetal lung maturation tests

Respiratory distress syndrome (RDS) is a serious impairment of breathing in newborn infants resulting from a lack of surfactant, a substance that lowers surface tension in the lung. RDS is often associated with premature birth. Although infants of diabetic mothers are thought to be at increased risk for surfactant-deficient RDS, some research reports have not found delayed lung maturation in such infants. To learn more about this issue, the outcome of pregnancy for 526 diabetic women was studied; all had undergone testing to determine the level of maturation of the fetal lungs. Three measures of fetal lung maturation were compared: (1) the lecithin/sphingomyelin ratio; (2) the phosphatidylglycerol concentration; and (3) the optical density of amniotic fluid (the fluid in which the fetus floats, removed during a procedure called amniocentesis). Eighteen infants had signs of respiratory distress within the first six hours of life, of whom five had surfactant-deficient RDS; five had transient tachypnea (rapid breathing) of the newborn; four had enlarged hearts; two had pneumonia; and two had other conditions. All neonates with surfactant-deficient RDS were identified by each of the three tests, and no infant whose tests indicated maturity of the lungs had surfactant-deficient RDS. The optical density test appeared excellent for evaluating these diabetic pregnancies. But on the whole, surfactant-deficient RDS was rare in these infants of diabetic mothers; most respiratory distress was associated with other conditions. Therefore the need to do fetal lung maturation testing in infants born to diabetics is questioned. (Consumer Summary produced by Reliance Medical Information, Inc.)