Preventing perinatal transmission of HIV: Your vigilance can pay off
These interventions can keep the risk of mother-to-child transmission at less than 2%.
Antiretroviral administration to infants. All HIV-exposed newborns receive ZDV as a standard part of perinatal transmission prevention,1 initiated as close to delivery as possible. Infants whose gestation was 35 weeks at birth receive an oral dose of 2 mg/kg (or 1.5 mg/kg intravenously if unable to take oral medications) within the first 6 to 12 hours after birth, then every 6 hours until 6 weeks of age. Infants less than 35 weeks’ gestation at birth receive 2 mg/kg orally every 12 hours (or 1.5 mg/kg intravenously), advancing to every 8 hours at 2 weeks of age if they were 30 weeks’ gestation at birth, or at 4 weeks of age if less than 30 weeks’ gestation at birth.
In unusual circumstances, such as when a mother is known to have a high viral load at delivery or an antiretroviral-resistant virus, other antiretroviral agents may be added to ZDV for infant prophylaxis.1 The decision to use additional antiretrovirals necessitates consultation with a pediatric HIV specialist, preferably before delivery.
With the exception of efavirenz—thought to have potential teratogenicity when administered in the first trimester of pregnancy1—antiretrovirals are generally considered safe in pregnancy and for newborns;7 rarely, significant organ system pathology due to mitochondrial toxicity has been observed in infants exposed to antiretrovirals.24 Prophylactic ZDV use may be associated with anemia in infants, but this is generally mild and resolves by 12 weeks of age without treatment.25 Follow-up of the data from PACTG 076 has shown no long-term adverse effects associated with ZDV.26
TABLE 1
Repeated HIV screening is recommended for pregnant women in their third trimester who meet these criteria14
| Women who receive health care in jurisdictions with elevated incidence of HIV or AIDS among women ages 15 to 45 years |
| Women who receive health care in facilities in which prenatal screening identifies at least 1 HIV-infected pregnant woman per 1000 women screened |
| Women who are known to be at high risk for acquiring HIV |
| Women who have signs or symptoms consistent with acute HIV infection |
| NOTE: A second HIV test during the third trimester, preferably <36 weeks of gestation, is cost effective even in areas of low HIV prevalence and may be considered for all pregnant women. |
| AIDS, acquired immune deficiency syndrome; HIV, human immunodeficiency virus. |
Providing care, Tx, support to mothers with HIV and their newborns
Prevention of perinatal HIV transmission does not end when an infant completes 6 weeks of ZDV therapy. The mother must have postpartum care and ongoing management of HIV infection; the infant must undergo assessment of HIV status and monitoring while receiving ZDV, and receive general infant care. The longitudinal, family-centered approach with family medicine offers an opportunity to optimize the overall wellness of a woman with HIV, including mental health, contraceptive counseling, cervical screening, and a decision on whether to continue antiretroviral therapy, based on clinical status (HIV disease stage) and immunologic (CD4) factors. 1
In the United States and other developed countries where safe and feasible formula feeding is possible, breastfeeding is not recommended for HIV-infected mothers, due to the risk of virus transmission via breast milk.1
Given that maternal antibodies to HIV cross the placenta and are detectable in HIV-exposed infants up to 18 months of age, antibody tests such as HIV ELISA and rapid HIV tests are not suitable for the diagnosis of HIV in infants.12 Rather, a virologic polymerase chain reaction (PCR) test must be used.1 While HIV DNA PCR is the gold standard for infant diagnosis, HIV RNA PCR is also sensitive and specific.1 HIV-exposed infants should receive routine childhood immunizations according to the usual schedule.1,27 HIV-infected infants should be referred to a pediatric HIV specialist.
Untreated HIV infection in infants may have a variable course, including rapid progression to AIDS and death.28 Often the first manifestation of rapid progression is Pneumocystis jiroveci pneumonia (formerly Pneumocystis carinii pneumonia), which may be seen even before HIV diagnosis is realized in an infant who becomes HIV-infected despite prophylaxis.1,29 Unless there is adequate proof to presumptively exclude HIV infection (negative results on 2 virologic tests conducted ≥2 weeks postpartum, 1 of which must be at least 4 weeks postpartum),1,29 all HIV-exposed infants should be started at age 6 weeks (after completion of ZDV prophylaxis) on trimethoprim-sulfamethoxazole (TMP-SMX, Bactrim, Septra) prophylaxis against Pneumocystis pneumonia. TMP-SMX prophylaxis should be continued until 2 virologic tests for HIV yield negative results.1 If TMP-SMX toxicity develops, dapsone and atovaquone are alternatives.29 TABLE 2 outlines the follow-up of HIV-exposed infants, including testing for HIV.
