August 28, 1998
In 1994, the Public Health Service (PHS) published guidelines for zidovudine (ZDV) use to reduce perinatal transmission of human immunodeficiency virus (HIV) (1), and in 1995 published guidelines for HIV counseling and voluntary testing of pregnant women (2). To directly assess the implementation of these guidelines and to identify barriers to the continued reduction of perinatal transmission, four states that conduct surveillance for HIV/acquired immunodeficiency syndrome (AIDS) (Louisiana, Michigan, New Jersey, and South Carolina) enhanced routine surveillance activities to conduct a population-based evaluation. This report summarizes the preliminary results of the evaluation, which identified 1) increases from 1993 to 1996 in the proportion of pregnant HIV-infected women in whom HIV infection was diagnosed before the birth of their child, 2) increases in the proportion of women offered ZDV and 3) lack of prenatal care as a critical obstacle to fully implementing the guidelines.*
HIV/AIDS registries in the four states were matched to birth registries for 1993 (used as a baseline year), 1995, and 1996 to identify all infants born to women who have been reported with HIV/AIDS and to determine the proportion of HIV-infected women who gave birth each year who had had HIV infection diagnosed before the birth. Data about HIV testing, ZDV receipt, and prenatal care were collected from medical records for the mother (prenatal and labor and delivery) and the infant (newborn and pediatric HIV clinic). A mother was considered to have had HIV infection diagnosed before delivery if her first HIV-positive test date preceded her infant's date of birth. The number of women giving birth who were identified from the surveillance and birth registry match and from routine HIV and AIDS case finding was compared with the total number of HIV-infected women giving birth that year or the most recent year available (determined from the Survey of Childbearing Women [SCBW] ( 3). In addition to mother-infant pairs identified through routine surveillance, the registry match identified an additional 10%-20% previously unreported perinatally exposed infants who were born to women in whom HIV infection had been diagnosed.
In the four states combined, the proportion of pregnant women in whom HIV infection was diagnosed before giving birth increased from 68% in 1993 to 81% in 1996 (Table 1). Among these women, 52% had positive HIV tests before the index pregnancy, and 48% had positive HIV tests during the index pregnancy. Charts were abstracted for 1038 mother-infant pairs in which HIV infection was diagnosed in the mother before delivery; these data represented approximately 80% of all women in whom HIV infection was diagnosed before delivery. From 1993 to 1996, the proportion offered prenatal ZDV increased from 27% to 85%, the proportion offered intrapartum ZDV increased from 5% to 75%, and the proportion offered neonatal ZDV increased from 5% to 76% (Table 1). Less than 5% of women offered ZDV refused it. Among the women who were not offered prenatal ZDV in 1996, most (74%) had had no or limited prenatal care (zero to four visits). During the 3 years, 14% of women in whom HIV infection was diagnosed before delivery had had no prenatal care; 35% of women who used illicit drugs during pregnancy had had no prenatal care, compared with 6% of women who did not use illicit drugs. In 1996, a total of 62% of all women in whom HIV infection was diagnosed before delivery, and 83% of women who had five or more prenatal-care visits received prenatal ZDV and intrapartum ZDV, and their infants received neonatal ZDV.
Reported by: G Melvin, K Corson, MPH, Louisiana Dept of Health. H Malamud, MPH, L Scott, E Mokotoff, Detroit Health Dept. L Dimasi, MPA, J Beil, MPH, S Costa, MA, S Paul, MD, New Jersey Dept of Health and Senior Svcs. N Harris, MSPH, J Lafontaine, MPH, South Carolina Dept of Health and Environmental Control. Div of HIV/AIDS Prevention -- Surveillance and Epidemiology, National Center for HIV, STD, and TB Prevention, CDC.
Editorial Note: The population-based data described in this report demonstrate the rapid implementation of the PHS guidelines. Their effectiveness in reducing perinatal transmission is reflected in substantial reductions (43% from 1992 to 1996) in perinatally acquired AIDS, especially among recent birth cohorts (4). The data identify obstacles to maximum reduction of perinatal transmission (e.g., inadequate prenatal care among drug-using women), demonstrate the success of voluntary testing for HIV during pregnancy, and in these four states provide a timely statewide assessment of the impact of the guidelines.
Lack of access to prenatal care or inadequate use of care is a critical obstacle to maximum reduction of perinatal transmission, especially among women who use illicit drugs. Overall, up to 15% of women who had HIV infection diagnosed before they gave birth had no prenatal care, and preliminary results from chart reviews of women tested after giving birth suggest that approximately 50% of these women had had no prenatal care. In the general population, 4% of women giving birth have late or no prenatal care (5). Women who use illicit drugs in pregnancy are at particularly high risk for not receiving prenatal care because of social disruption, fear of criminalization, and lack of access to care. Efforts must be made to improve use of prenatal care among these women, to ensure receipt of care after HIV infection is diagnosed (both to prevent perinatal transmission and for their own care) and to improve access to substance-abuse treatment and prevention.
In the four states described in this report, counseling and voluntary HIV testing was successful in identifying a high proportion of HIV-infected pregnant women. Although lack of prenatal care may be the primary reason HIV-infected women are not tested before giving birth, not being offered the test or refusing it also are factors. Studies of the acceptance of HIV testing by pregnant women after counseling have shown consistently high acceptance rates (2,6,7). Surveys of providers, however, have shown that although they tend to agree that all women should be tested for HIV, in practice some providers tend to offer testing only to women whom they consider at risk for HIV infection ( 8,9). Risk-based testing identifies fewer HIV-infected women than routine voluntary testing of all pregnant women (2,7). Women are increasingly being infected through heterosexual contact and may not know their partner's risk for HIV infection (2), making risk-based testing increasingly less effective for women. Finally, although prenatal care is an important opportunity to offer testing to prevent perinatal transmission, ideally women should know their HIV status before becoming pregnant. Sites serving women of childbearing age should counsel and offer voluntary testing to all women, including adolescents -- regardless of whether they are pregnant (2).
The decrease in the number of HIV-infected women giving birth in these four states primarily is due to decreases in New Jersey. The number of HIV-infected women giving birth has declined since 1989 in the Northeast, reflecting in part an older epidemic compared with other parts of the country (10).
In these four states, the proportion of women in whom HIV infection is diagnosed before giving birth is likely to be underestimated for four reasons. First, although evaluations have shown completeness of HIV reporting to be very high, HIV reporting is unlikely to be 100% complete, resulting in women who have tested positive for HIV infection not being listed in HIV/AIDS registries. Second, reporting delays likely affect the completeness of 1996 case ascertainment (the most recent year for which preliminary analyses of data are available). Third, a woman's first positive HIV test could be earlier than the date listed in the registry. Finally, records for women whose names have changed might fail to match records in other registries.
Reporting of HIV infection among adults and among perinatally exposed and perinatally infected children was critical to the states' ability to conduct timely evaluation of perinatal HIV-prevention activities. Because of the high level of completeness of case ascertainment compared with the SCBW, these methods can provide data to estimate trends in the number of HIV-infected childbearing women where states are unable to conduct this seroprevalence survey using local resources. The participating states will use their findings to target local HIV-prevention efforts (e.g., prenatal care outreach). Six states (Alabama, Colorado, Indiana, Missouri, Tennessee, and Virginia) have initiated similar evaluations. As additional states implement integrated HIV and AIDS surveillance, evaluations of recommendations for HIV prevention and treatment can be assessed more widely among pregnant women and other at-risk or infected populations.
*Single copies of this report will be available free until August 28, 1999, from the National Prevention Information Network (operators of the National AIDS clearinghouse), P.O. Box 6003, Rockville, MD 20849-6003; telephone (800) 458-5231 or (301) 519-0459.
SCBW is an anonymous population-based seroprevalence survey of routinely collected blood samples from newborns tested for maternal HIV antibody. For Louisiana, Michigan, and South Carolina, SCBW data from the corresponding year or from the most recent year available (1995) were used; in New Jersey, a linear extrapolation was used to estimate the number for 1996 because of steady decreases since 1991.