Eradication of perinatal HIV may be within reach

OB/GYN News, Nov 15, 2001 by Sherry Boschert

Twenty years into the AIDS epidemic, obstetrics boasts the brightest victory in battling the virus.

Vertical transmission rates in the United States dropped 10-fold after introduction of highly active antiretroviral therapies in the mid-1990s. With proper maternal treatment and perinatal prophylaxis, an HIV-positive woman's chance of infecting her newborn is less than 1%, compared with 28% in women with no treatment.

That's less than the overall 3% risk for having a child with a major birth defect. It's such a small risk that more and more HIV-positive women--now living with the virus as a chronic disease thanks to better treatments--are opting to have children, said Dr. William M. Gilbert, director of maternal-fetal medicine at the University of California, Davis.

Indeed, some physicians now are willing to do donor inseminations from HIV-positive male partners.

Few U.S. obstetricians see patients with HIM and those who do usually refer the women to multispecialty groups of HIV experts. After two decades, however, the disease has drastically altered medical practice as a whole. (See related story.)

For obstetricians especially, the AIDS epidemic drove home the importance of universal precautions, Dr. Gilbert said.

The risk of HIV contamination in blood products changed his approach to postpartum anemia. Before the era of HIM if a woman was a little anemic after delivery with a hematocrit of perhaps 25%, Dr. Gilbert might have given her a unit or two of blood. "Sometimes now down to a hematocrit of 20% or 15% we don't give blood" after delivery to avoid the risk of blood contaminants such as HIV, hepatitis C, or others, he said.

All obstetricians now are expected to test for HIV in as many women as possible and to talk about safer sex with women who screen negative for the virus and have multiple sexual partners. The U.S. Public Health Service recommended universal prenatal HIV counseling and testing with consent in 1995. At least 43 states now have informed consent and/or pretest HIV counseling laws that are applicable to pregnant women.

Nearly half of pregnant women diagnosed with HIV have no identifiable risk factor for the disease, noted Dr. Patricia Robertson of the University of California, San Francisco. Heterosexual women who do not use IV drugs now account for dose to one-third of all new HIV cases each year.

The proportion of women among people with HIV has increased over time. A 1999 study of states with HIV reporting found that females comprised 64% of 13- to 19year-olds with HIV, 44% of 20- to 24-year-olds, and 29% of those older than 25. In 1982, females comprised only 12% of HIV cases.

"I've learned to offer [HIV testing] in a way that I get probably 98% compliance," Dr. Robertson said.

Some of the stigma of having HIV still remains, she added. Some HIV-positive women still insist on keeping their infection secret from their families. "We have to be careful when hanging the IV bottle" so that the treatments are not obvious during delivery, Dr. Robertson continued.

HIV affects decisions about the mode of delivery. The American College of Obstetricians and Gynecologists advises delivery at 38 weeks' gestation for women with HIV infection to avoid the onset of labor or rupture of membranes before delivery, factors that increase the risk of neonatal infection. ACOG also recommends counseling any pregnant woman with a high HIV viral load (more than 1,000 copies/mL) about the risks and benefits of cesarean delivery before the onset of labor and the rupture of membranes. Scheduled C-sections lower the likelihood of vertical transmission but are associated with higher maternal morbidity rates in women with HIV.

The AIDS epidemic brought obstetricians, pediatricians, perinatologists, and infectious diseases specialists closer together and focused their attention on the link between a woman's health and that of her child. "It has linked the two inextricably in a way that we really should always have done," commented Dr. Andrew Pavia, an infectious diseases specialist who treats both adults and children with HIV at the University of Utah, Salt Lake City.

Worldwide, 1,600 infants each day are born infected with HIM but in the United States each year only approximately 200 babies are born with the virus. Most of these infants are born to the approximately 15% of all HW-infected pregnant women who receive no prenatal care.

The HIV epidemic is far from over. New infection rates have leveled off, and there's been a recent increase in national rates of gonorrhea, a sexually transmitted disease long associated with HIV transmission. As preventive efforts have failed to stop the epidemic, public health experts increasingly place their hopes in vaccine research, with little success so far. Rates of drug-resistant virus are on the rise, casting doubt on the ability of current antiretroviral medicines to continue fending off AIDS.

In obstetrics, at least, the goal of completely stopping transmission from mother to infant may be feasible. "I think in the United States we will come very close to eliminating perinatal transmission if we summon the will and fix the problems in delivering prenatal care," Dr. Pavia maintains.