What is the recommended treatment for preventing mother to child HIV (Human Immunodeficiency Virus) transmission in pregnant women who are HIV positive?

Prevention of Mother-to-Child HIV Transmission

All HIV-infected pregnant women should receive combination antiretroviral therapy (HAART) as early as possible in pregnancy—ideally containing zidovudine—with continuation through labor (including intravenous zidovudine infusion) and delivery, followed by 6 weeks of zidovudine prophylaxis for the infant. 1, 2

Universal HIV Testing Strategy

• Perform documented, routine HIV testing for all pregnant women using "opt-out" consent (notify patient that testing will be performed unless declined) 1, 2
• Repeat HIV testing in the third trimester for women at high risk of HIV acquisition 1, 2
• For women in labor with undocumented HIV status, perform rapid HIV antibody testing immediately with results available within 12 hours of birth 1, 2
• If rapid test is positive, initiate antiretroviral prophylaxis immediately without waiting for confirmatory testing 1

Maternal Antiretroviral Therapy Regimens

For Women Already on HAART When Pregnancy Discovered

• Continue current HAART regimen throughout pregnancy 1, 3
• Discontinue teratogenic drugs immediately (efavirenz) or drugs with adverse maternal potential (stavudine + didanosine combination) 1, 3
• Do not stop antiretroviral drugs during first trimester if woman requires treatment for her own health 1
• If discontinuation is necessary, stop all drugs simultaneously (exception: for drugs with long half-lives like nevirapine, continue nucleoside analogues for 3-7 days after stopping the NNRTI to prevent resistance) 1, 3

For Treatment-Naive Women Requiring HAART

Women meeting treatment criteria (WHO stage 4, stage 3 with CD4 <350 cells/mm³, or stage 1-2 with CD4 <200 cells/mm³) should receive HAART 1

• Preferred regimen: zidovudine + lamivudine + nevirapine 1
• Alternative regimen: zidovudine + lamivudine + lopinavir/ritonavir 1
• Consider delaying initiation until after first trimester if clinically stable 1, 3
• Avoid nevirapine in women with CD4 >250 cells/mm³ due to severe hepatotoxicity risk 1, 3
• Zidovudine should be included in antiretroviral regimens whenever possible as it remains the mainstay of perinatal prevention 1, 3

For Women Not Requiring HAART for Their Own Health (Viral Load >1000 copies/mL)

Recommended regimen starting at 28 weeks gestation: 1, 3

• Zidovudine twice daily from 28 weeks
• Single-dose nevirapine at labor onset
• Zidovudine + lamivudine during labor
• Zidovudine + lamivudine for 7 days postpartum (the "tail" reduces nevirapine resistance development from 60% to 10%) 1

Intrapartum Management

• Administer intravenous zidovudine as continuous infusion during labor for all HIV-infected women 1, 3
• Elective cesarean delivery at 38 weeks is recommended if plasma HIV RNA remains >1000 copies/mL at 34-36 weeks gestation or viral load is unknown 1, 2, 3, 4
• Cesarean delivery reduces transmission risk by approximately 50% in women with elevated viral loads 3, 4

Infant Prophylaxis

Standard Risk (Mother Received Adequate Antenatal ART with Viral Suppression)

• Zidovudine for 6 weeks starting within 6-12 hours after birth 1, 2, 3, 5
• Dosing: 2 mg/kg orally every 6 hours 5

High Risk (No Maternal Antenatal ART or Poor Viral Suppression)

• Single-dose nevirapine (2 mg/kg) at birth PLUS zidovudine for 6 weeks 3
• Initiate prophylaxis as soon as possible after birth, ideally within 6 hours but certainly by 12 hours 1, 6

Infant Feeding

• In the United States and resource-rich settings: HIV-infected mothers should NOT breastfeed regardless of maternal ART use 2, 3, 4
• Formula feeding eliminates postnatal transmission risk when safe alternatives exist 2
• In resource-limited settings, WHO recommends breastfeeding for at least 12 months with full ART adherence support 2

Postpartum Maternal Management

• Evaluate need for continued therapy after delivery 1, 3
• If woman does not meet criteria for treatment in nonpregnant adults, consider discontinuing therapy after delivery 1
• Stop all drugs simultaneously unless regimen includes long half-life drugs 1, 3
• For nevirapine-containing regimens, continue dual nucleoside analogues for 3-7 days after nevirapine discontinuation to reduce resistance risk 1, 3

Expected Outcomes

• Without intervention: 15-45% transmission risk 2
• With effective ART: <5% transmission risk (as low as 1-2% with combined interventions) 2, 7
• ACTG 076 trial demonstrated 68.7% relative reduction in transmission (7.8% with zidovudine vs 24.9% with placebo) 5

Critical Pitfalls to Avoid

• Failure to test pregnant women for HIV is the most significant missed prevention opportunity 2
• Delayed initiation of antiretroviral therapy significantly reduces effectiveness 2
• Stopping antiretroviral drugs during first trimester in women requiring treatment increases transmission risk 1
• Using nevirapine in women with CD4 >250 cells/mm³ risks severe hepatotoxicity 1, 3
• Failing to administer the zidovudine/lamivudine "tail" after single-dose nevirapine increases maternal resistance (from 10% to 60%) 1
• Not administering infant prophylaxis within 12 hours of birth reduces efficacy 1, 6

Monitoring Requirements

• Close blood count monitoring is essential, especially for patients with advanced disease, as neutropenia and anemia are the major toxicities of zidovudine 5
• Monitor liver function closely in women receiving nevirapine, particularly those with CD4 >250 cells/mm³ 3
• Anemia occurs in 22% of neonates receiving zidovudine (vs 12% placebo), but transfusion is rarely required and values normalize within 6 weeks 5