HIV infection and zidovudine use in childbearing women

The risk of vertical HIV transmission from mother to child has been shown to be markedly decreased through HIV education, counseling, testing, and zidovudine (ZDV) use. The US Public Health Service published guidelines in 1994 for the use of ZDV on the basis of results of the AIDS Clinical Trials Group Protocol, a multicenter clinical trial of ZDV. The Public Health Service followed these guidelines with recommendations for routine HIV counseling and testing with informed consent for all pregnant women. New Jersey adopted these guidelines as the standard of care and created a program implementing the standard in all hospitals with maternity units. The purpose of this report was to study the trends in the rate of HIV infection in childbearing women over the past decade and to follow patterns of use of ZDV in the HIV-positive women, as a marker for the success of New Jersey's policy and program to reduce mother-to-child transmission.

Since 1988 in New Jersey, blood from heel-stick filter papers has been tested for the presence of HIV antibody through anonymous, unlinked surveys. Excess blood from screening for inborn errors of metabolism for all infants who were born in the state from July through September of each year was tested using a Food and Drug Administration-approved HIV-1 and Western blot test. Age, race, and ethnicity were recorded, as well as the results from the HIV-1 and Western blot tests. Since 1994, specimens confirmed to be HIV-1 positive by Western blot test were tested for the presence of ZDV, and the results were recorded.

The number of New Jersey women included in the study for the period 1990 through 2002 numbered 372305. The percentage of childbearing women who tested positive for HIV declined by 55% during the period, although the declines were not uniform in all subgroups. In the early 1990s, women who were <30 years old had higher infection rates than older women, but this has not been a consistent pattern during the period. Younger women again had a higher rate in 2002. When HIV-positive rates are examined by 5-year age groups, the declines are dramatic for younger women. The rate per 100 women 20 through 24 years decreased from 0.46 per 100 tested women in 1990 to 0.29 in 2002 and for women 25 through 29 years from 0.51 per 100 in 1990 to 0.25 in 2002. The rate for women 30 through 34 years of age declined from 0.54 in 1990 to 0.13 in 2002. During the same time period, the rate per 100 tested women 35 though 39 years of age increased from 0.23 to 0.33. Black non-Hispanic women who give birth to live infants have the highest HIV-positive rates, followed by Hispanic women and white non-Hispanic women. In 2002, this rate was 0.74 per 100 in black non-Hispanic women, 0.22 per 100 in Hispanic women, and 0.08 in white non-Hispanic women. Although major disparities continue, the infection rate in black non-Hispanic women demonstrated the greatest decrease during the period, followed by the decline among Hispanic women. The use of ZDV in HIV-positive women increased dramatically during the period, from 13.3% in 1994, when it was first tested in New Jersey, to an all-time high of 88.5% in 2002.

Reducing perinatal HIV transmission is a priority for the New Jersey Department of Health and Senior Services. Reducing perinatal transmission can be accomplished by reducing the number of infants who are exposed perinatally or decreasing the percentage of exposed infants for whom transmission occurs or both. The decrease in prevalence of HIV-positive status in childbearing women is in opposition to an overall increasing trend in prevalence rates. This decrease is thought to be attributable in part to the positive impact of numerous education and prevention programs but may also be the result of a voluntary decision on the part of HIV-infected women not to become pregnant or not to carry to term. In addition, the cohort of women who became infected in the early years of the epidemic may be aging out of their childbearing years, may have more advanced disease with a concomitant difficulty with fertility and carrying to term, or may have died. In New Jersey, a greater proportion of women with newly diagnosed HIV disease are past their childbearing years as compared with earlier years. Increased use of ZDV is thought to be attributable to several factors: dissemination of information to health care providers via continuing medical education activities; dissemination of information to the public, in particular to women; outreach via community-based organizations; and New Jersey Department of Health and Senior Service regulations and policies for mandatory counseling and voluntary testing of all pregnant women. A recent addition to New Jersey's comprehensive program to decrease perinatal transmission occurred in 2002 with dissemination to hospitals of the department's standard of care for women who present in labor with unknown HIV status. Physicians, nurses, and hospitals play vital roles in preventing vertical transmission of HIV by providing preconception and postconception counseling, testing with consent of pregnant women, and treatment for HIV-positive mothers, including administration of ZDV. This study not only provides an estimate of the prevalence of HIV infection in the population of childbearing women but also provides a means of examining the vertical transmission of HIV infection from mother to child. Continued research on this subpopulation as well as on other groups will provide additional knowledge to help in the overall goal of reducing HIV prevalence.