Prevention of perinatal transmission of HIV infection.

The University of Alberta Pediatric HIV Clinic serves an area with an estimated population of 1.2 million, with 25 000 births annually. Records were reviewed from Jan. 1, 1988, to Dec. 31, 1999, for all children born in northern Alberta to women with HIV infection to determine our success rate at preventing perinatal HIV transmission. A child was considered to be HIV infected if he or she had 2 positive HIV polymerase chain reaction (PCR) results from tests performed on separate blood samples. A child was considered to be uninfected if she or he had seroreverted or had 2 negative HIV PCR results at 1 or more months of age, with 1 being obtained at 4 or more months. Indeterminate HIV status was assigned to a child who had a single negative HIV PCR result or had not been tested at 4 or more months of age. The ethnicity of the mothers was also recorded by clinic physicians to determine whether there was an identifiable high-risk group that could be targeted in programs aimed at preventing the transmission of HIV to young women. Forty-three women had HIV infection that was diagnosed prior to labour (Fig. 1). The antiretrovirals given during pregnancy consisted of zidovudine alone in 20 cases, 2 reverse transcriptase inhibitors in 6 cases, a protease inhibitor with 2 reverse transcriptase inhibitors in 7 cases and a nonnucleotidase reverse transcriptase inhibitor with 2 reverse transcriptase inhibitors in 4 cases. When mothers were treated with antiretrovirals during pregnancy and intrapartum, 31 of 36 babies (86%) were not HIV infected. All infants received at least some oral zidovudine in the first 6 weeks of life, except in 2 cases in which the mothers refused all treatment. Five infants received more than one antiretroviral drug as HIV perinatal prophylaxis. Fig. 1 also shows the HIV status of 18 children born to women who had HIV infection at the time of delivery but whose infection was diagnosed after delivery (2 women had 2 pregnancies before being tested). Forty percent of these children (n = 7) were HIV infected. Positive HIV status before delivery was deduced either because older siblings were subsequently found to be HIV infected or because these children were still HIV seropositive when first seen in our clinic. These children were all under 6 years of age when first seen and had no other risk factors for acquiring HIV infection. Prevention of perinatal transmission of HIV infection