MOTHER-TO-CHILD TRANSMISSION OF HIV

Key points

• HIV infection can be transmitted from an infected mother to her fetus during pregnancy, during delivery, or by breastfeeding.
• Maternal transmission to the fetus occurs most commonly in the perinatal period. (50-65%)
• It is very unlikely that mother-to-child transmission will occur if the mother’s level of plasma viremia is <1000 copies of HIV RNA/mL of blood and extremely unlikely if the level is undetectable (i.e., <50 copies/mL).

Risk factors for transmission

1. High maternal levels of plasma viremia.
2. Closer human leukocyte antigen (HLA) match between mother and child.
3. Prolonged interval between membrane rupture and delivery.
4. Presence of Chorioamnionitis at delivery
5. STIs during pregnancy
6. Illicit drug use during pregnancy
7. Cigarette smoking
8. Preterm delivery
9. Obstetric procedures (amniocentesis, amnioscopy, fetal scalp electrodes, and episiotomy)

Preventive measures

• cART – Antiretroviral therapy (Continous)
• Cesarean section delivery

World Health Organization guidelines recommend that all pregnant HIV-infected women should receive life-long cART for the health of the mother and to prevent perinatal transmission regardless of plasma HIV RNA copy number or CD4+ T cell counts.

Relation with Breastfeeding

The risk factors for mother-to-child transmission of HIV via breast-feeding include

• Detectable levels of HIV in breast milk
• The presence of mastitis
• Low maternal CD4+ T cell counts
• Maternal vitamin A deficiency

The risk of HIV infection via breastfeeding is highest in the early months of breastfeeding. In addition, exclusive breast-feeding has been reported to carry a lower risk of HIV transmission than mixed feeding.

In developed countries, breastfeeding of babies by an HIV-infected mother is contraindicated since alternative forms of adequate nutrition, i.e., formulas, are readily available. In developing countries, where breastfeeding may be essential for the overall health of the infant, the continuation of cART in the infected mother during the period of breastfeeding markedly diminishes the risk of transmission of HIV to the infant. In fact, once cART has been initiated in a pregnant woman, it should be continued for life.

Reference-Harrison's Principles of Internal Medicine 20th edition