Genes in Mother & Baby Raise Risk of Preterm Birth

http://abcnews.go.com/Health/wirestory?id=9743107&page=2

U.S. government researchers have found that genes in the mother and the fetus play a role in the risk of preterm labor, a leading cause of infant death and disability. Gene variants in the mother and fetus can make them susceptible to an inflammatory response to infections inside the uterus, increasing the risk that a baby will be born early.

A preterm baby (born before 37 weeks of gestation) has a 120 times greater risk of death than a baby born full term. Survivors are at risk for breathing difficulties, bleeding into the brain, and having a significant neurological handicap. "Preterm births cost the U.S. $26 billion per year. It is one of the most serious and significant challenges to medicine and society and one whose importance is not fully recognized," said Dr. Roberto Romero of the National Institutes of Health.

The findings of this study support the notion that preterm delivery is an evolutionary mechanism intended to protect baby and mother from infection. "We have established that one of every 3 premature babies is born to a mother who has an intra-amniotic infection," Romero said.

After analyzing 190 genes and more than 700 DNA variants from 229 women and 179 premature infants in Chile, they found that the strongest gene influence was the interleukin receptor, which is involved in the baby's response to inflammation. In the mother, the team focused on one gene called tissue inhibitor of metalloproteinase 2, or TIMP2, which affects structures in the cervix and uterus that get broken down at the start of labor.

Romero said that when there is an infection, the combination of these 2 genetic profiles raises the risk of preterm labor as the body attempts to save the mother's and baby's lives. The hope is that these findings may leas to genetic tests that assess whether a woman is predisposed to premature labor.