The Short Answer
Your baby will receive antiretroviral prophylaxis (preventive medicine) for 4–6 weeks and undergo HIV testing at 14–21 days, 1–2 months, and 4–6 months of age. With maternal viral load undetectable and newborn prophylaxis, >99% of babies are born HIV-free [9].
Newborn HIV testing uses DNA or RNA polymerase chain reaction (PCR), which detects the virus's genetic material in blood. A single positive test doesn't confirm HIV; two consecutive positive tests confirm infection. Testing at 14–21 days catches early transmission (during pregnancy or delivery), testing at 1–2 months catches later transmission, and testing at 4–6 months confirms final status [9]. Maternal antibodies (which cross the placenta) can give false positives until 12–18 months, so PCR testing is essential.
Here's the biological timeline: if your baby was exposed to HIV during pregnancy or delivery, the virus begins replicating in the baby's blood within days to weeks. PCR testing detects viral RNA or DNA at levels as low as 50 copies/mL, making it far more sensitive than antibody tests. Newborn prophylaxis (zidovudine) blocks the virus from replicating, so even if the baby was exposed, the medicine prevents infection [9].
In real life, if your viral load was undetectable at delivery and your baby received prophylaxis on schedule, the chance of a positive test is <1%. Most families get their first negative result at 14–21 days and breathe a huge sigh of relief. If any test is positive, your pediatric HIV specialist will start your baby on full antiretroviral therapy immediately [9].
Try This Today
Write down your baby's testing dates: 14–21 days, 1–2 months, and 4–6 months. Bring these dates to every pediatric visit. Ask your pediatrician to call you with results within 48 hours so you're not left wondering.