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Prevention of Mother-to-Child Transmission (MTCT)
Antenatal periodDuring the antenatal period, a woman can be tested voluntarily to determine whether she is HIV-positive. Testing during this period offers several advantages. If a woman is negative, she and her partner can be counseled on risk reduction. This may be particularly important in areas where taboos on sexual activity during pregnancy or postpartum might cause a man to seek other partners, thereby placing a woman at risk when she resumes sexual activity with her partner. If a woman is positive, she can receive early counseling on the prevention of MTCT and on maintaining health; she can make decisions about future fertility and about termination; if it is a safe and legal option, and she can take steps to prevent exposing partners. Finally, she can plan for treatment and follow-up for the baby. If a woman is positive, she can also receive support to maintain her health, including proper nutrition, treatment of STIs, and care for other infections, such as tuberculosis (TB) or malaria. If a woman is positive, and if AZT (zidovudine or ZDV) is available, she might receive treatment during the prenatal period to reduce the risk for transmission to the child. A long course of AZT therapy can reduce the probability of transmission by 66%, but it is generally not available or too costly in developing countries. Short-course regimens, which are still expensive but less costly than long-course regimens, can reduce the risk for transmission by up to 50%. This treatment must be initiated during the antenatal period. It is important to remember that antiretroviral medications are not available or affordable in much of the world, and administration for the prevention of MTCT does not benefit the mother directly. Labor and deliveryDuring labor and delivery, the risk for transmission can be reduced by avoiding invasive procedures. Providers should avoid fetal scalp pH, artificial rupture of membrane, and routine episiotomy. They should minimize instrumental delivery and lacerations and should make efforts to prevent postpartum hemorrhage. Of course, as always, providers should adhere strictly to infection prevention precautions. Evidence shows that performing a cesarean section prior to the onset of labor can reduce the risk of infection up to fourfold because it minimizes the exposure of the child to maternal body fluids. However, most studies have been done in developed countries, and some emerging evidence suggests that a cesarean section may increase maternal morbidity and mortality. It is important to consider the limitations of resource-poor settings, as well as the difficulties of performing cesarean sections, including cost, logistics related to complications, anesthesia, supplies, drugs, trained staff in the operating theater, and postop nursing care. Finally, and most promising, is the administration of nevarapine to reduce the risk of MTCT. A single dose of neverapine to the mother during labor and a dose to the child within 48 hours have been found to reduce the risk of transmission by 50% at a very low cost. An additional benefit is that nevarapine can be administered even in the absence of prenatal care. Like AZT, however, this treatment does not benefit the mother directly—and it is still not available in much of the developing world. PostpartumThe risk of MTCT can be reduced during the postpartum period through interventions related to breastfeeding. Decisions about whether and how to breastfeed can be complicated. While replacement feeding with formula would eliminate the risk of transmitting HIV through breast milk, this decision must be weighed against the risk of infant morbidity and mortality that occurs when infants are not breastfed due to artificial feeding in countries where clean water is not readily available, and formula is not available or affordable. Breastfed infants are at significantly reduced risk for death due to both gastrointestinal (15% of infant mortality) and respiratory (18% of infant mortality) infections during the first year of life. It is estimated that exclusive breastfeeding has reduced the infant mortality by approximately 6 million deaths, or 67%. Additionally, in some cultures, avoiding breastfeeding, when it is the norm, can stigmatize a woman as being HIV-positive. The risk of HIV infection through breastfeeding appears to be greatest in the first few months of life and is lower among infants who are fed breast milk exclusively than among those who are breastfed and receive supplemental foods or liquids; this is often referred to as mixed feeding. In a recent study in South Africa (Coutsoudis, et al.), babies who were breastfed exclusively were significantly less likely to become infected in the first three months than were those who had mixed feeding. According to the researchers, contaminants or allergens in the supplements provided to children with mixed feeding could undermine breast milk’s benefits to the immune system, and contaminants might harm membranes in the lining of the gut, thereby creating portals of entry for HIV contained in breast milk. When the risks of morbidity and mortality related to artificial feeding are weighed against the risks of HIV infection through breastfeeding, the protective effect of exclusive breastfeeding appears to level off at about six months. While this information is very preliminary, it is leading some researchers and providers to advocate exclusive breastfeeding up until six months of age, followed by abrupt weaning. Mixed feeding, while the norm in many places, is not recommended. While the debate about breastfeeding recommendations related to MTCT goes on, at this time, the official World Health Organization (WHO) recommendations remain that women should breastfeed, unless they know they are HIV-positive and have “full access” to artificial feeding. In May 1997, UNAIDS, WHO, and UNICEF presented a combined policy statement on HIV and infant feeding. The statement provides policymakers with a number of key elements important for establishing a policy on HIV and infant feeding. They include:
It is important to note that while rates of MTCT have been reduced in developed countries, the rates remain high in resource-constrained countries largely due to the lack of access to existing prevention interventions, including replacement feeding, selective cesarean section, VCT, and antiretroviral drug therapy. In sum, a variety of interventions and precautions can be taken during the antenatal period, during labor and delivery, and postpartum to reduce the risk for MTCT of HIV. It is important to remember, however, that the most effective way to prevent such transmission is to prevent the woman from becoming infected in the first place, and to provide access to family planning to HIV-positive women who want to prevent pregnancy.
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By
the end of 1999, 3.8 million children had died from HIV/AIDS, and an additional
1.3 million children were living with HIV/AIDS. Most of these children
acquired HIV from their mothers. HIV can be transmitted from an infected
mother to her child during pregnancy, labor and delivery, or breastfeeding.
Without intervention, the probability that an infected woman’s child
will become infected is about 25 to 35% in the developing world, and about
a third of that is through breastfeeding. A variety of interventions and
precautions can be taken during each of these periods—antenatal,
labor and delivery, and postpartum—to reduce the risk for infection.
These prophylactic practices are not absolute, but they do reduce the
risk for transmission considerably.
