Cocaine triggers premature labor.

It is estimated that 15% of America's childbearing-age women abuse drugs. Those who become pregnant and use cocaine are at particular risk for perinatal complications ranging from miscarriage to premature labor. Approximately one-quarter of such pregnancies end before term, although no one really knows why.

"On the street, people say cocaine causes uterine contractions and premature labor. But no one's ever studied or confirmed that observation scientifically, because widespread cocaine use during pregnancy is a fairly new phenomenon," indicates William W. Hurd, an assistant professor in the Department of Obstetrics and Gynecology, University of Michigan Medical Center. "So far, all we really know for sure is that 25% of babies born to cocaine users are delivered prematurely."

In a study of the effects of cocaine on the pregnant human uterus at the cellular level, Hurd and his colleagues have demonstrated that the drug interferes with the metabolism of the body's naturally occurring stress hormones, which in turn produces uterine...