Background: The mechanism of mother-to-child transmission (MTCT) of HIV-1 is not well described.
Methods: Of 328 HIV-infected mother-infant pairs, we identified 91 that had discordant angiotensin I-converting enzyme and glutathione S-transferase M1 alleles. Maternal alleles in cord blood were quantified with real-time polymerase chain reaction, as indicators of microtransfusions.
Results: HIV-1 infected infants had more maternal DNA in cord blood than their uninfected counterparts. Increased maternal DNA in cord blood was associated with preterm delivery, low birth weight, and maternal immunosuppression.
Conclusion: Intrapartum MTCT was associated with placental microtransfusions. The associations among placental microtransfusion, in-utero MTCT, maternal immunosuppression, and poor birth outcome should be further investigated.