The impact of in utero exposure to highly active antiretroviral therapy (HAART) on longitudinal growth of HIV-uninfected infants is unknown. The Mashi and Mma Bana PMTCT intervention trials enrolled HIV-infected pregnant women at four sites in Botswana. Breast-fed (BF), HIV-uninfected infants born at 37 weeks or greater were included in this analysis. Weight-for-age (WAZ), length-for-age (LAZ), and weight-for-length (WLZ) z-scores were calculated using World Health Organization Child Growth Standards. Mean z-scores were compared between in utero antiretroviral exposure groups using Student t test, response profiles analysis, and general linear mixed effects modeling. Growth of 619 HAART-exposed and 440 zidovudine-exposed, HIV-uninfected infants was evaluated. Mean birth weights were 3.01 kg for HAART and 3.15 kg for zidovudine-exposed infants (P < 0.001) with lower mean birth WAZ, length-for-age (LAZ), and weight-for-length (WLZ) among HAART-exposed infants (all P < 0.001). HAART-exposed infants had greater improvement in WAZ and weight-for-length (WLZ) from birth through 2 months (P = 0.03, P < 0.001, respectively). The WAZ did not differ between groups from 3 through 6 months (P = 0.26). Length-for-age (LAZ) remained lower in HAART-exposed infants but the incidence of wasting or stunting did not differ between exposure groups. Lower weights in HAART-exposed uninfected infants at birth were rapidly corrected during the first 6 months of life.
