Improving Birth Outcomes Meeting the Challenge in the Developing World (2003) / Chapter Skim
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8. Preventing Perinatal Transmission of HIV
8. Preventing Perinatal Transmission of HIV
Pages 262-292
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From page 263... ...
Despite their promise, however, such interventions are not common in the developing world. This chapter describes the scope of the HIV/AIDS epidemic, focusing on heavily infected populations where mother-to-child transmission occurs most frequently, and reviews the evidence for a variety of potential interventions to prevent perinatal transmission of HIV.
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From page 264... ...
By comparison, women constitute about 20 to 40 percent of HIV-infected adults in North America, Western and Central Europe, Latin America, North Africa and the Middle East. The relatively high prevalence of HIV in women of childbearing age in developing countries increases the risk of perinatal transmission (joint United Nations Programme on HIV/AIDS, 2001; Newell, 2000~.
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From page 266... ...
And since maternal mortality negatively affects children's survival, children who were not infected at birth would still face an increased risk of death after losing their mothers to AIDS. Perinatal Transmission of HIV Transmission of HIV from mother to child can take place in utero, intrapartum, or postpartum through breastieeding (Mofenson, 1997~.
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From page 267... ...
A randomized trial in Nairobi, Kenya, that compared breastieeding and formula feeding found that breastieeding increased the risk of HIV transmission by 16.2 percent, which accounted for 44 percent of HIV infection in the breastieeding arm of that study. Most 75 percent of the risk difference between the two arms of the study occurred in the first 6 months, but transmission continued throughout the duration of exposure (Nduati et al., 2000~.
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From page 268... ...
Research indicates that with appropriate antiretroviral therapy and elective cesarean delivery, perinatal HIV transmission rates can be reduced to less than 2 percent (Mandelbrot et al., 2001~. Table 8-1 summarizes the conditions and results of several key trials described below, many of which were conducted in developing countries.
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From page 269... ...
With the advent of two- and three-drug combinations to reduce viral loads in people with AIDS, researchers began to evaluate benefits of combining ZDV with other antiretroviral agents to prevent perinatal HIV transmission. Mandelbrot and colleagues (2001)
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From page 270... ...
women in US and starting at 14-34 weeks gestation France Intra: 2 mg/kg ZDV IV for 1 hour, then 1 mg/kg ZDV IV per hour until delivery Post: 2 mg/kg orally 4x daily for 6 weeks Bangkok trial Nonbreastieeding Pre: 300 mg ZDV orally 2x daily 6 mot (Shaffer et al., women in Thailand starting in 36th week of pregnancy 1999) Intra: 300 mg ZDV every 3 hours Perinatal HIV Nonbreastieeding Short Pre: 300 mg ZDV orally 2x 6 mot Prevention Trial women in Thailand daily starting at 35 weeks gestation (PHPT)
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From page 271... ...
PREVENTING PERINATAL TRANSMISSION OF HIV ~r-to271 Risk of Transmission ( % of Children) ther, HIV Status Relative Reduction Evaluated Control Treatment in Risk (in %)
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From page 272... ...
24 mot Nonbreastieeding ACTG 076 regimen (historical 18 mot women in France controls) ACTG 076 regimen plus 150 mg 3TC orally 2x daily starting at 32 weeks gestation and 2 mg/kg orally 2x daily for 6 weeks to child PETRA (Petra Study Mostly breastieeding Intra: 300 mg ZDV every 3 hours 6 wk.
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From page 273... ...
PREVENTING PERINATAL TRANSMISSION OF HIV 273 Risk of Transmission ( % of Children) ther, HIV Status Relative Reduction Evaluated Control Treatment in Risk (in %)
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From page 274... ...
: 200 mg NVP orally at 24-48 hours postpartum A recent Cochrane Review (Brocklehurst and Volmink, 2002) stated that one large randomized trial demonstrates that nevirapine given to the mother as a single dose at the onset of labor and to the infant as a single dose within 72 hours of birth is more effective than an intrapartum and post partum regime of zidovudine.
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From page 275... ...
While some antiretroviral drugs have been shown to be carcinogenic in rodents, no such effects have been detected in short-term human studies or reported to a registry maintained by the drugs' manufacturers (Culnane et al., 1999; Mofenson and McIntyre, 2000~. Overall, it is likely that the risk of serious
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From page 276... ...
These authors have recommended that antiretroviral treatment to prevent perinatal HIV transmission be limited to ZDV alone to minimize the dangers of mitochondrial damage or toxicity. Recent evidence of toxic side effects from NVP, including severe liver damage in health care workers who took the drug for postexposure prophylaxis, has been attributed to taking multiple doses of the drug; a single dose is typically used to prevent perinatal HIV transmission.
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From page 277... ...
However, safe and effective cesarean sections are not available to many women in the developing world, and some studies in both developing and industrialized countries have found an increased rate of maternal complications in HIV-infected women who have undergone the procedure (Mofenson and McIntyre, 2000~. Thus, cesarean section may be an appropriate strategy for preventing perinatal transmission of HIV, but only when performed in appropriately staffed and equipped health facilities, where the risks associated with cesarean section are low.
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From page 278... ...
However, when these conditions are not fulfilled, in particular in an environment where infectious diseases and malnutrition are the primary causes of death during infancy, artificial feeding substantially increases children's risk of illness or death" (WorId Health Organization, Joint United Nations Programme on HIV/AIDS, 1998~. Breastieeding has been promoted for many years for its reduction of mortality due to infectious diseases including neonatal sepsis, acute respiratory infections, and diarrhea (Arifeen et al., 2001; Ashraf et al., 1991; World Health Organization Collaborative Study Team, 2000~.
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From page 279... ...
Table 8-2 summarizes the results of several studies that examine antenatal HIV screening and the subsequent treatment of women who test positive, as well as their infants, to prevent HIV infection. Although the details of these studies differ, all indicate that perinatal HIV prevention programs can be effective at a relatively low cost.
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From page 280... ...
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From page 282... ...
Many observers believe that a life is worth saving whatever the risks that the child faces later in life, and that antenatal HIV screening with prophylaxis offers many children a chance to live into adulthood. Moreover, it can be argued that the main risks facing children saved from HIV infection can themselves be mitigated.
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From page 283... ...
, and where prevalence rates may be higher, counseling and informed consent for HIV testing in antenatal care should be more intensive and focused on helping women make informed choices for themselves. Guidelines for Antenatal HIV Screening A recent summary of the characteristics of a well-organized perinatal public health screening program (Institute of Medicine, 1999)
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From page 284... ...
· The test and intervention should be acceptable to the affected popuGiven the evidence discussed in this chapter, and understanding "treatment" as short-course ZDV or intrapartum NVP intended to prevent transmission to the infant, antenatal HIV screening programs would likely be judged to be ethically appropriate in most developing countries where the prevalence of HIV in childbearing mothers is high and where resources exist to treat them. RECOMMENDATIONS Antenatal screening and prophylaxis programs represent the most immediate means to reducing perinatal HIV transmission.
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From page 285... ...
· Identifying effective and efficient ways to implement antenatal HIV screening programs in developing country settings. · Discovering effective counseling techniques that increase women's awareness of the risks and benefits of antenatal HIV screening and encourage them to make informed choices regarding testing.
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From page 286... ...
Because stigma and discrimination associated with HIV infection may pose a considerable barrier to diagnosis, successful programs to prevent perinatal transmission will need to educate pregnant women about the risks and benefits of antenatal HIV screening and prophylaxis. Clearly, the most reliable means of preventing perinatal HIV transmission is to prevent infection among women of childbearing age.
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From page 287... ...
1994. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment.
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From page 288... ...
1999. Maternal levels of plasma human immunodeficiency virus type 1 RNA and the risk of perinatal transmission.
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From page 289... ...
2002. Antenatal vitamin A supplementation increases birth weight and decreases anemia among infants born to human immunodeficiency virus-infected women in Malawi.
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From page 290... ...
1999. Risk factors for perinatal transmission of human immunodeficiency virus type 1 in women treated with zidovudine.
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From page 291... ...
World Health Organization Collaborative Study Team, 2000. Effect of breastieeding on infant and child mortality due to infectious diseases in less developed countries: a pooled analysis.
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