Government research shows a rapid HIV test can be used on women during childbirth, results that doctors hope will help reduce HIV infections in newborns.

HIV infection of newborns is not widespread in the United States, but is of great concern in Africa and other developing areas.

Interrupting the experience of childbirth to test and tell a woman she’s infected may seem cruel - but it gives doctors a good chance of preventing her baby from becoming infected, too, said study co-author Dr. Mardge Cohen.

It takes about 20 minutes to get results from rapid tests for HIV. Testing during childbirth allows doctors to begin treating the mother during labor - when most mother-to-infant infections occur - and to start preventive treatment in newborns.

“It is a very difficult time and a very special time, and to learn very bad news but to have the opportunity to do something about that” is helpful, said Cohen, an AIDS specialist at Chicago’s John H. Stroger Jr. Hospital of Cook County. The study is reported in Wednesday’s issue of the Journal of the American Medical Association.

The federal Centers for Disease Control and Prevention estimates that about 300 U.S. infants are born each year infected with the virus that causes AIDS, despite recommendations for prenatal HIV testing and use of AIDS drugs during pregnancy in infected women.

About 700,000 children worldwide developed HIV infections last year, most in Africa and from mother-to-child transmission during childbirth or early infancy. The problem is acute in southern Africa, where about 1 in 5 pregnant women has HIV but is unaware of it.

Without drug treatment before birth for mothers and shortly thereafter for newborns, babies born to infected women have a 25 percent chance of becoming infected. With optimal treatment of the mother, the transmission rate drops to less than 2 percent, Cohen said. The odds increase if the mother isn’t treated until she’s in labor, but are better than those with no treatment at all.

In the study, HIV was diagnosed in three of 34 babies born to HIV-infected women who were tested and treated during labor. The study involved 5,744 untested women at 16 U.S. hospitals who were asked to undergo rapid testing during labor. The majority - 84 percent or 4,849 women - consented.