Vertical transmission of human immunodeficiency virus from seronegative or indeterminate mothers.

UNLABELLED OBJECTIVE--To describe the identification of human immunodeficiency virus (HIV)-infected infants born to women who were seronegative or indeterminate during pregnancy. RESEARCH DESIGN--Longitudinal cohort study. SETTING--Inner-city medical center. PARTICIPANTS A series of children born to women with histories of risk factors for HIV infection were followed up for studies of the natural history of HIV-infected infants. These children were identified through risk factor assessment of pregnant women presenting for obstetric care. INTERVENTIONS--Counseling and testing to detect HIV. RESULTS--Three women were retrospectively identified who were infected with HIV during pregnancy but whose test results showed them to be either seronegative or indeterminate. Two of these women transmitted HIV infection to their children. Subsequently, all three women were confirmed to be infected. CONCLUSIONS--Standard serologic testing to detect HIV infection will not identify all infected pregnant women. Perinatal transmission of HIV can occur in women with negative results of enzyme-linked immunosorbent assay or indeterminate results of Western blot analysis during pregnancy.