The epidemiology of perinatal transmission of HIV.

ABSTRACT

PIP The range of issues in the epidemiology of perinatal infection with HIV covers prevalence of HIV in women, types of HIV transmission to the fetus and newborn, problems with testing for HIV infections in neonates, variations in effectiveness of transmission to infants, maternal, fetal and perinatal mortality. In the U.S. 75% of all pediatric AIDS cases are traceable to HIV-positive mothers, but numbers are small. In Central Africa, seroprevalence in women is about 5%, and perinatal HIV is significant. HIV has been demonstrated in fetal tissues and cord blood, indicating transmission in utero. Transmission at birth has not yet been documented. Transmission of HIV after birth, presumably via breastfeeding, has been shown in at least 8 cases. No information is available on HIV titers in breast milk. Diagnosis of HIV infection in newborns is problematic. Cord blood cultures, the p24 antigen test, and the in situ hybridization method are feasible but impractical in most clinics. The Western blot test for IgM-specific antibodies is not specific or sensitive enough for infants. A new method called [DNA] polymerase chain reaction (PCR) is capable of detecting acquired HIV infection, and may be useful in clinics, since it does not require radionuclides. In 11 studies the incidence of HIV infection in infants of seropositive mothers ranged from 8-65%. There is some indication that the stage of the HIV disease, and possibly socioeconomic status, of the mother affect the transmission of the virus. There is no indication that pregnancy worsens maternal HIV status, although there is a suggestion that mothers may worsen in the postpartum period. Several studies show increased incidence of low birth weight and prematurity, associated with higher infant mortality, in newborns of HIV-positive mothers. No effective programs of screening or counseling women at risk of HIV infection and pregnancy have been reported.^ieng