WOMEN\Shortened cervix may cause premature labor.

Byline: Jason Kahn Medical Tribune News Service

Researchers may have identified an important factor that could help doctors predict which pregnant women will go into premature labor - a cervix that is abnormally short, according to a new report.

In a study of 2,900 pregnant women, those whose cervixes were shortened 24 weeks into the pregnancy had a substantially higher risk of premature birth than other women.

The researchers used ultrasound to measure the cervix, a ring of uterine muscle that protrudes into the vagina. They found that the shorter a woman's cervix, the higher the risk that she would give birth prematurely.

Women with the shortest cervixes (13 millimeters long or less) at 24 weeks of pregnancy had 14 times the risk of a premature birth compared to women with the longest cervixes (40 millimeters long or greater), according to the study, published recently in the New England Journal of Medicine.

A shortened cervix may indicate an improperly functioning birth canal. When the short cervix is combined with abnormal activity of the uterus, it could bring about premature labor, suggested the researchers, led by Dr. Jay Iams of Ohio State University.

"We'd like to incorporate using vaginal ultrasound to measure cervix length in women at high risk of preterm delivery," said Dr. Robert Hayashi, chief of maternal/fetal medicine at the University of Michigan Medical Center in Ann Arbor. "Then, if we can predict who is going to have a premature birth, maybe we can tailor the care we give."

For instance, women with shortened cervixes may need more prenatal-care visits, or more frequent testing for vaginal infections that could further contribute to premature delivery, Hayashi said.

Measuring the cervix with ultrasound also may help doctors decide which women could benefit from a procedure known as cerclage, in which the cervix is stabilized with sutures to keep it from opening prematurely, Iams suggested.

Finding ways to prevent premature delivery would be worthwhile, said Dr. Sabrina Craigo of the Tufts University School of Medicine in Boston, who wrote an editorial accompanying the study. Premature deliveries are the second-most important contributor to infant deaths, and occur in 10 percent of all pregnancies, she said.