Objective: To assess hematologic and hepatic toxicities associated with in utero and breastfeeding exposure to maternal highly active antiretroviral therapy (HAART) among infants in Botswana.
Design: A nested cohort study within a randomized clinical trial (the Mashi Study). Laboratory toxicities among infants born to women who initiated HAART before delivery were compared with toxicities among those born to women who received zidovudine and a single dose of nevirapine or placebo in labor. Infants were randomized to breastfeed with extended zidovudine or to formula-feed.
Methods: Hemoglobin concentrations, absolute neutrophil and platelet counts, and alanine aminotransferase and aspartate aminotransferase levels were recorded from birth to 7 months of age in infants. Grade 3 and 4 toxicities were compared by infant antiretroviral exposure status.
Results: In-utero exposure to maternal HAART was associated with increased risk for neutropenia in infants up to 1 month of age; 21.7% of HAART-exposed infants were neutropenic, compared with 5.5% of the infants exposed to zidovudine (P < 0.01). However, neutropenia was no longer associated with antenatal exposure to HAART after 1 month of age. Postnatal exposure to HAART was not associated with hematologic or hepatic toxicities. Laboratory toxicities were clinically asymptomatic in all but one infant.
Conclusion: Exposure to maternal HAART in utero may increase the risk for infant neutropenia, particularly among breastfed infants, but the clinical significance of this finding is uncertain. The lack of association between exposure to HAART through breastfeeding and long-term toxicities in infants is reassuring but deserves study in larger cohorts.