'It's astonishing how people still don't understand that this can happen to almost anybody. Women don't always know if their partners have had other sex partners.'

The US Preventive Services Task Force said in 1996 there was insufficient evidence that screening all pregnant women had any benefit. The independent panel of medical experts said in Tuesday's Annals of Internal Medicine that scientific advances have changed that.

"We're hoping that this will encourage women to think of HIV testing during pregnancy the way they think of all other testing during pregnancy," said Dr. Diana Petitti, the task force's vice chairman and a scientific adviser for Health Policy and Medicine for Kaiser Permanente Southern California.

'This Can Happen to Almost Anybody'

HIV-infected pregnant women can be given combination-drug therapies, have Caesarean sections or avoid breastfeeding to help keep their babies safe, reducing the risk to as low as 1 percent, the task force said.

Otherwise, infected women have a 1-in-4 chance of passing AIDS on to their babies. Of the 4.7 million women hospitalized for pregnancy or childbirth in 2002, nearly 6,300 had HIV.

The recommendation follows a 2001 directive by the federal Centers for Disease Control and Prevention, which emphasized HIV testing "as a routine part of prenatal care and strengthened the recommendation that all pregnant women be tested for HIV," CDC spokeswoman Jessica Frickey said.

There are many women who don't know they have the virus, said Sharon Hillier, a professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine.

"It's astonishing how people still don't understand that this can happen to almost anybody. Women don't always know if their partners have had other sex partners," Hillier said.

No Shame

About 40,000 Americans are infected with HIV each year, and about 27 percent of those are women. Many pregnant women are offered the tests but turn them down.

Petitti said women need to know new HIV tests are nearly 100 percent accurate and there is no shame in acknowledging they might be at risk.

Hillier said the more universal testing becomes, the less stigma will be associated with it.

In addition to its recommendations about pregnant women, the task force reaffirmed its recommendation that adolescents and adults at increased risk for HIV be tested.

The task force broadened its definition of high-risk to include those getting care at homeless shelters or clinics specializing in the care of sexually transmitted diseases.