Mother-to-Child Transmission of HIV Infection: Timing, Risk Factors and Strategies for Prevention
Pp. 27-43 (17)
Mother-to-child transmission of human immunodeficiency virus type 1
(HIV) occurs during gestation, during delivery, and during breast feeding. In an
unprotected mother-child pair, transmission over-all occurs in 30-40%, with about one
quarter of these transmissions in utero, one half during delivery, and one quarter during
breast feeding. Most in utero transmission occurs in the third trimester. There are many
risk factors for transmission, but the most important are the maternal viral load and the
maternal CD4 concentration. Antiretroviral treatment of the mother has a potent
preventive effect but must be administered throughout the risk period (that is, from
early second trimester through the end of breast feeding). For in utero and intrapartum
transmission, treatment probably acts through two mechanisms, namely pre-exposure
prophylaxis in the fetus or newborn, and reduction in maternal viral load. Adequate
voluntary counseling and testing for HIV and access to antiretroviral drugs are now
critical preventive issues in this important mode of transmission.
Antiretroviral therapy, Breast feeding, CD4 concentration, Delivery,
HIV, Mother-to-child transmission, Pregnancy, Viral load.
Harvard Medical School, Division of Infectious Diseases, BCH3104, Boston Children’s Hospital, 300 Longwood Ave., Boston, MA 02115, Enders Rm 861.3, USA.