The predictive value of maternal HIV-1 RNA load over mother-to-child transmission depends on maternal CD4 levels.

Forty-four anti-HIV seropositive pregnant women were enrolled in a study of maternal factors related to mother-to-infant human immunodeficiency virus type 1 (HIV-1) transmission. HIV-1 infection was documented in 11 of 45 infants (24.4%). Obstetric factors, maternal CD4 counts, and disease stage were not related to the risk of transmission. HIV-1 RNA levels at delivery were significantly higher in mothers who transmitted the infection (P = .024). A strong relationship between viral load and risk of transmission was observed in women with stage A1 (P= .006), but not in those with stages A2-A3. These results suggest that vertical transmission of HIV-1 is multifactorial and that viral load plays a major role in mothers with early-stage HIV-1 infection.