In the United States, approximately 5,000 women living with HIV infection give birth each year.¹ Since the initial Pediatric AIDS Clinical Trials Group Protocol 076 (PACTG 076) study was published in 1994, advances in the management of HIV infection have led to a dramatic decline in the incidence of perinatally infected infants.^2,3 The annual rate of perinatal HIV transmission has decreased by more than 95% in the United States since the early 1990s.^2,3 In 2017, only 73 infants were born with HIV infection in the United States. Five states (Florida, Texas, Georgia, Louisiana, and Maryland) accounted for 38% of infants born with HIV infection in the United States in 2016.^4–6

Antenatal testing and treatment of pregnant women have reduced vertical transmission rates; however, opportunities remain to further decrease vertical transmission, and inadequate antenatal testing for HIV persists.^7,8 The Centers for Disease Control and Prevention wants to eliminate perinatal HIV transmission in the United States, with a goal of reducing perinatal transmission to an incidence of less than one infection per 100,000 live births and a rate of less than 1% among HIV-exposed infants.^8–10

Perinatal Transmission

Perinatal transmission of HIV can occur in pregnancy, labor and delivery, and breastfeeding, with the greatest risk during labor and delivery.¹¹ Strategies to prevent mother-to-child transmission include giving antiretroviral therapy (ART) to mothers with HIV infection and their infants, scheduling cesarean deliveries for women with an HIV RNA load greater than 1,000 copies per mL or an unknown viral load at the time of delivery, and providing formula instead of breast milk to infants of mothers living with HIV. [corrected] Infants at highest risk of vertical transmission include those whose mothers have a viral load greater than 1,000 copies per mL within the four weeks before expected delivery, who received no ART or less than four weeks of ART by the time of delivery, who have advanced maternal HIV disease, or who acquired HIV infection during pregnancy or breastfeeding.^11–13

Current Guidelines for Perinatal HIV Management

All pregnant women should be screened for HIV when establishing prenatal care and with each pregnancy.¹² Those found to be HIV-positive should start ART.¹² Repeat testing in the third trimester is recommended for women who are at increased risk of acquiring HIV infection (i.e., women who inject drugs, exchange sex for money or drugs, have sex partners with HIV infection, or have a sexually transmitted infection during pregnancy). Any woman who presents in labor without a documented HIV-negative test result should have expedited HIV testing.¹⁴ A positive test result should prompt intrapartum intravenous zidovudine (ZDV; Retrovir) for the mother and an antiretroviral regimen for the infant after delivery.¹⁴

A scheduled cesarean delivery at 38 weeks' gestation is recommended for pregnant patients with an HIV RNA load greater than 1,000 copies per mL or an unknown viral load at the time of delivery to minimize perinatal transmission of the virus.^13,14 In the PACTG 076 study, antepartum ZDV, intrapartum ZDV, and six weeks of ZDV prophylaxis for the infant decreased perinatal transmission by 66%.³ Based on this study, continuous intravenous ZDV during labor was recommended for all pregnant women with HIV infection. However, a more recent study found that intrapartum ZDV did not affect the risk of perinatal HIV transmission among women with an HIV RNA viral load of less than 400 copies per mL at the time of delivery.¹⁵ Current recommendations state that intravenous ZDV should be administered only to women with an HIV RNA viral load greater than 1,000 copies per mL on polymerase chain reaction testing or if the viral load is unknown at the time of delivery.^12,14,16