Over the past several years, the United States has documented dramatic declines in mother-to-infant (perinatal) transmission of HIV, indicating the success of recent perinatal prevention efforts. But new data from the Centers for Disease Control and Prevention (CDC) points to continuing challenges to ensure that all HIV-infected women have the opportunity to benefit from this success.
In 1994, clinical trials showed that HIV-infected women could reduce the risk of transmitting the virus to their babies by as much as two-thirds through administration of zidovudine (ZDV or AZT) during pregnancy, labor, and delivery, and by giving their babies AZT for the first 6 weeks after birth. In 1994, the Public Health Service (PHS) issued guidelines for using AZT during pregnancy, and in 1995, published guidelines for routinely counseling all pregnant women about HIV and offering them an HIV test. As health care providers across the country incorporated these guidelines into clinical practice, perinatal AIDS incidence dropped dramatically. Yet, two CDC studies point to remaining barriers to prevention.
An eight-city study presented today at the 12th World AIDS Conference, by CDC researcher Jeanne Bertolli, Ph.D., indicates that while most HIV-exposed children (81%) in 1995 received at least one component of the drug regimen proven effective, only half (61%) received the full drug regimen. The study analyzed the medical history of over 1,100 babies born to HIV-infected women to assess how widely preventive guidelines were being implemented. The most common reasons for not receiving the full treatment regimen were no prenatal care and refusal of the treatment.
Because the study was based on data from 1995, it likely under represents the number of children now benefiting from therapy. But according to Bertolli, the barriers identified continue to have relevance today. "There is no question that the lack of access to early prenatal care remains the principle barrier to providing all infected pregnant women in the U.S. the best chance to prevent infection to their children."
Bertolli stressed that counseling plays a critical role in helping women understand the benefits and risks of treatment.
A related poster presentation by CDC researcher Pascale Wortley, M.D., supports these findings and also calls for improved prenatal care. In a four-state study (Michigan, New Jersey, Louisiana, and South Carolina), the proportion of HIV-infected pregnant women diagnosed before giving birth increased from 68 percent in 1993 to 79 percent in 1996. However, 14 percent of these women had no prenatal care and 22 percent had limited prenatal care (fewer than 5 visits). Women who had used illicit drugs in pregnancy were especially likely to have no or limited prenatal care.
The great majority of women diagnosed before giving birth were offered AZT, and the proportion offered AZT in pregnancy increased from 27 percent in 1993 to 85 percent in 1996. Fewer than 5 percent of women refused AZT. Women who received no or little prenatal care were much less likely to be offered AZT, pointing to the critical need to reach women at greatest risk with early prenatal care.
We have made significant gains in the U.S. in translating science into life-saving prevention, but clearly there is more work to be done," said Helene Gayle, M.D., M.P.H., Director of CDC's National Center for HIV, STD, and TB Prevention. "As is always true with prevention, the solutions aren't simple or easy to implement. But the efforts we have made have resulted in clearly documented benefits."