Ans: This is called perinatal transmission of mother-to-child transmission. Mother-to-child transmission is the most common way children get HIV. Recommendations for HIV testing of all pregnant women and starting HIV treatment immediately reduce the number of babies born with HIV. If an HIV-positive woman takes HIV medication as prescribed during pregnancy and childbirth, and gives her baby HIV medication 4 to 6 weeks after birth, the risk of transmission may be less than 1%.