Prevention of Mother to Child Transmission of HIV
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Direct answer
Prevention of mother to child transmission of HIV is a combined strategy of maternal antiretroviral therapy, infant prophylaxis, safe delivery and feeding advice. Lifelong antiretroviral therapy for every pregnant and breastfeeding woman living with HIV is the most important intervention under current national and WHO guidance. Infants are tested with HIV DNA PCR early, because antibody tests are uninformative before about 18 months due to transplacental maternal antibodies.
What you must remember
- Maternal ART: lifelong antiretroviral therapy for all pregnant and breastfeeding women with HIV, aiming at viral suppression.
- Viral load: a high or unknown viral load near term favours elective caesarean section at 38 weeks.
- Infant prophylaxis: a short course of antiretroviral drug is started at birth and extended if breastfeeding continues, as set by national guidance.
- Early infant diagnosis: HIV DNA PCR on a dried blood spot, first at about six weeks of age.
- Feeding: breastfeeding is recommended when the mother is on ART with a suppressed viral load, and replacement feeding is advised only if it is acceptable, feasible, affordable, sustainable and safe.
- Final status: an HIV antibody test after 18 months confirms the infant's status.
- Positive infant: an infant with a positive result is referred urgently for ART.
A pathway from diagnosis in pregnancy to the infant's final status
A woman is diagnosed with HIV in her second trimester, and her baby is due in about four months. Each stage of care lowers the risk of transmission to the child.
- Start maternal ART early. Begin lifelong antiretroviral therapy once HIV is diagnosed in pregnancy, aiming for viral suppression before delivery.
- Plan the delivery. Check the viral load near term, since a high or unknown load favours an elective caesarean section at 38 weeks, while a suppressed woman can deliver by the usual obstetric indications.
- Give infant prophylaxis. Start antiretroviral prophylaxis for the newborn after birth, following national guidance on the drug and its duration.
- Test the infant early. Send HIV DNA PCR from a dried blood spot at about six weeks, and repeat testing according to the schedule.
- Counsel on feeding. Advise breastfeeding with maternal viral suppression, and use replacement feeding only when the acceptability, feasibility, affordability, sustainability and safety criteria are met.
- Confirm status later. An antibody test after 18 months confirms the infant's final HIV status.
Where the exam tries to catch you
Students lose marks here by mixing up the infant test with the maternal test.
- Trap: using an antibody test in a 6-month-old to rule out infection Correct: maternal antibodies cross the placenta, so the infant needs HIV DNA PCR, and antibody testing is valid only after 18 months.
- Trap: stopping maternal ART at delivery Correct: lifelong ART continues after delivery and through breastfeeding, because stopping raises the risk of transmission through breast milk.
- Trap: advising formula feeding automatically Correct: breastfeeding with a suppressed maternal viral load is recommended, and replacement feeding is advised only when the safety criteria are met.
Frequently asked questions
When is HIV DNA PCR used for an infant born to a mother with HIV?
HIV DNA PCR is the test for infants born to mothers with HIV, first sent at about six weeks of age from a dried blood spot. Repeat testing follows the national schedule, because antibody tests are unreliable in infants before 18 months.
Why is an infant antibody test not used before 18 months?
Antibody testing is not used before 18 months because maternal IgG antibodies cross the placenta and remain in the infant's blood. A positive antibody result therefore cannot separate maternal antibody from infant infection, so PCR is used instead.
What is the role of maternal ART in preventing mother to child transmission of HIV?
Maternal ART is the most important intervention, because it suppresses the viral load and reduces transmission during pregnancy, delivery and breastfeeding. Therapy continues after delivery and throughout breastfeeding, rather than being stopped at childbirth.
Is breastfeeding allowed for an infant born to a mother living with HIV?
Breastfeeding is recommended in the Indian programme when the mother is on ART and her viral load is suppressed. Replacement feeding is advised only if it is acceptable, feasible, affordable, sustainable and safe for the family.