Teenage girls who become pregnant have long been known to face a higher risk of having premature babies and other complications, and a new study says biological factors may be an important reason.
Researchers at the University of Utah said Wednesday that a study of more than 130,000 pregnancies indicated that teenagers faced higher risks than older women even when such risk factors as low income, poor education, bad health habits like smoking, and inadequate access to health care are taken into account.
The scientists say the results suggest that biological problems associated with the immature bodies of the youngest mothers may contribute to prematurity and low birth weights among their offspring.
Although no one knows exactly, they speculated that young mothers might compete with their fetuses for certain nutrients or that their wombs might not be sufficiently developed.
The study, being published today in The New England Journal of Medicine, challenges the belief that pregnancy problems associated with young mothers are mostly related to their poor socioeconomic status, including the fact that many are poor, undereducated, come from racial minorities and get poor prenatal care.
The researchers found that even white, middle-class teenagers who get good health care are almost twice as likely as older women to deliver premature babies.
The study “challenges the contention that teenage mothers who receive adequate prenatal care will have reproductive outcomes as good as, or better than, those of older mothers,” said the researchers from the university and the state’s Vital Records Bureau.
“Our study adds a new dimension to the problem of teen pregnancy,” said Dr. Richard Ward, the senior researcher. “Even if you take care of all the other major social and behavioral factors associated with poor birth outcomes in teenage mothers, you’re still going to be left with a problem.”
Ward, working with Alison Fraser and John Brockert, analyzed the birth records of 134,088 white, firstborn infants born in Utah between 1970 and 1990 to girls and women aged 13 to 24.
The researchers limited their study to white, largely middle-class girls and women who, as a group, tend to have the lowest risk of problem births in an effort to isolate the causes.
The researchers found that girls aged 13 to 17 were nearly twice as likely to deliver prematurely than older mothers in the group.