in incidence between 1991 and 1995 were in women in the South and younger women, those who were 14 to 18 years old in 1988 (Wortley and Fleming, 1997).

Approximately 6,000 to 7,000 HIV-infected women give birth every year (Byers et al., 1998). According to the SCBW, overall, 17 per 10,000 women giving birth are infected with HIV (Davis et al., 1995). Trend data show a relatively steady national rate of HIV prevalence in childbearing women between 1989 and 1994, the last year for which data are available. There are, however, important regional variations. In the Northeast, where the epidemic started and peaked earliest, a 25% decline occurred in the number of HIV-infected childbearing women between 1990 and 1994. In the South, where the epidemic started later, there was a 25% increase between 1989 and 1991, and a level trend thereafter. The West and Midwest had stable and relatively low rates (Appendix D).

Estimates of the proportion of children born to HIV-infected women who are themselves infected with HIV vary, ranging from 14% to 33% in studies performed in the United States and Europe before the ACTG 076 (AIDS Clinical Trials Group protocol number 76) results became known. More recent estimates of the transmission rate, reflecting partial implementation of the ACTG 076 protocol, range from 3% to 10% (see Chapter 4).

Perinatally Transmitted Aids

Taking into account changing prevalence and transmission rates, perinatal transmission of HIV accounted for a cumulative total of 7,335 AIDS cases and an unknown number of HIV-infected children in the United States as of December 1997 (CDC, 1997c). There were 473 cases of pediatric AIDS (i.e., under age 13 at time of diagnosis) reported in 1997, and a total of 8,086 since the beginning of the epidemic (CDC, 1997c). Of the 473 cases in 1997, 432 (91%) were born to mothers with or at risk for HIV infection, as shown in Table 3.1. The breakout by mother's risk indicates that 107 (25%) of the known perinatally transmitted cases had mothers who used injection drugs, and an additional 60 (14%) of the mothers had sex with an injection drug user. Drug use is probably responsible for a substantial proportion of the cases born to the 249 (58%) mothers with HIV infection whose risk is not specified or who had sex with an HIV-infected person whose risk is not specified. Injection drug use, therefore, is associated with between 39% and 72% of perinatally acquired AIDS.

The number of reported perinatally acquired AIDS cases rose rapidly in the late 1980s and early 1990s, peaked around 1992, and subsequently declined by approximately 43% by 1996 (see Figure 3.1). In 1997, 473 cases of pediatric AIDS were reported (CDC, 1997c).2 This decline was due to a number of factors.

2  

The 1997 figure is not adjusted for reporting delays, so is not comparable to the numbers in Figure 3.1.



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