HIV can be passed from a birthmother to child during pregnancy, labor, delivery or breastfeeding. Transmission rates are approximately 35% if the mother and child are not treated (this average varies in different parts of the world and twins have a higher transmission rate). The best way to prevent transmission is for the mother to stay on a course of anti-retroviral therapy(ARV) throughout the pregnancy, and for the newborn baby to receive medicine as well. In this scenario, transmission rates fall to 1%.
All newborn babies carry their birthmother’s antibodies. A baby born to a mother with HIV will test positive to an HIV antibody test, until the mother’s antibodies leave the baby’s bloodstream, which can take up to 18 months. This does not mean that the baby has HIV. The recommended HIV test for babies 18 months or younger is a PCR test which tests the baby’s DNA (not the antibodies).
Negative: HIV infection can reasonably be excluded among HIV exposed children with two or more negative DNA PCR tests performed at age greater than one month and one of those being performed at or greater than four months. Negative DNA PCR tests drawn when the infant is less than 28 days do not exclude HIV infection, particularly if the infant has been exposed to antiretroviral medication in utero or after birth.
Positive: An infant is diagnosed as infected at any age by two positive DNA PCR tests performed on separate specimens.