Head Start for Survival

Each year, 50,000 U.S. infants die soon after birth--at least 25,000 of them from respiratory distress syndrome (RDS). Also called hyaline membrane disease, RDS is caused by the inability of an infant's lungs to extract oxygen from the air and pass carbon dioxide out of the body. Even when such babies (most of them premature) survive, they may suffer permanent brain damage.

The reason the lung does not function properly is simply that it has not yet matured. One remedy for RDS is to delay birth until the lungs mature, but this requires a prenatal test to determine the lungs' condition--something that doctors have always lacked.

Now the missing test has been devised by Dr. Louis Gluck, chief of the Division of Neonatology at the University of California in San Diego. Gluck studied the tiny air sacs that constitute the functioning surface of the lung, where the actual transfer of gases between the air and the blood occurs. When normal lungs exhale, the sacs are held open by fatty substances called lipids. But in RDS infants, Gluck found, these lipids are absent. Result: the victim breathes harder, the air sacs collapse, and soon the lungs stop functioning.

Ask the Lung. Gluck's research team discovered that the fetal lung generally matures around the 35th week of pregnancy. This development is signaled by a change in the amniotic fluid surrounding the fetus. At that point, the level of a phospholipid known as lecithin usually rises sharply and surpasses the level of another lipid, sphingomyelin. To determine if this has occurred normally, the Gluck test uses transabdominal amniocentesis, a technique that involves inserting a sterile needle through the abdomen into the womb, drawing off a sample of amniotic fluid and measuring the lipid levels.

"We ask the lung directly if it is mature enough to come out and breathe," says Gluck. If the lung answers yes, the baby can be delivered immediately by induced labor or caesarean section. If the answer is no, labor can often be delayed until the lung is mature enough to function. Performed on more than 400 women in the past two years, the Gluck test has thus far proved 100% accurate.

This file is automatically generated by a robot program, so reader's discretion is required.