Transmission From Mother to Newborn is Preventable if Viral Load is <1000 copies/ml at Delivery (1%)

Ioannidis and colleagues conducted a meta-analysis that combined individual patient data from 7 European and U.S. prospective studies of maternal infant-transmission. Data were collected on several potential predictors of transmission for mother-infant pairs where the maternal viral load at or closest to delivery was <1000 copies/ml.

A total of 44 cases of vertical HIV-1 transmission were identified among 1,202 women with HIV-1 RNA <1000 copies/ml at or close to delivery. The transmission rate was only 8/834 (1.0%) for mothers receiving antiretroviral treatment during pregnancy and/or delivery vs. 36/ 368 (9.8%) for untreated mothers. In multivariate analysis adjusting for study, transmission was lower with antiretroviral treatment, cesarean section, greater birth weight and higher CD4 cell count. In 12/44 cases, multiple RNA measurements were obtained during pregnancy, delivery or within 4 months postpartum; in 10/12 cases, the average was <500 copies/ml.