A Prospective Study of Infants Born to Women Seropositive for Human Immunodeficiency Virus Type 1

Assessment of the risks of transmission of infection with human immunodeficiency virus type 1 (HIV-1) from mother to newborn is difficult, partly because of the persistence for up to a year of maternal antibodies transmitted passively to the infant. To determine the frequency of perinatal transmission of HIV infection, we studied from birth 308 infants born to seropositive women, 62 percent of whom were intravenous drug abusers. Of 117 infants evaluated 18 months after birth, 32 (27 percent) were seropositive for HIV or had died of the acquired immunodeficiency syndrome (AIDS) (n = 6); of the 32, only 2 remained asymptomatic. Another 76 infants (65 percent) were seronegative and free of symptoms, whereas 9 (8 percent) were seronegative but had symptoms suggestive of HIV-1 infection. The infants infected with HIV-1 did not differ from the others at birth with respect to weight, height, head circumference, or rate of malformations, but as compared with newborns who were seronegative at 18 months, their serum IgM levels were higher (78±81 mg per deciliter vs. 38±39 mg per deciliter; P