Strategies Outlined for Reducing HIV Transmission. (Prenatal Screening, Scheduled C-Section).

AMELIA ISLAND, FLA. -- Rates of perinatal transmission of HIV have decreased dramatically in the last decade, but many HIV-positive women remain at risk of transmitting the virus to their baby, Dr. B. Denise Raynor said at an ob.gyn. update sponsored by Emory University.

Groups who are at risk for perinatal HIV transmission are late presenters who didn't receive prenatal care, women seen for prenatal care but not offered voluntary counseling or testing due to perceived low risk of infection, HIV-infected pregnant women who are not compliant with prescribed - antiretroviral medication, and women who are unexplained failures to therapy.

Dr. Raynor of Emory University Atlanta, presented two scenarios to illustrate the appropriate management of HIV-positive pregnant women.

* A 25-year-old woman presents for prenatal care at 35 weeks' gestation. She is HIV-positive but is not taking antiretroviral therapy The results of her CD4 count and HIV RNA levels are pending, but the test results will probably not be available by the time of delivery.

Even though the patient's viral load is unknown, because she is not taking antiretroviral therapy, it can be assumed that it is greater than 1,000 copies/mL. Having RNA levels less than 1,000 copies/mL significantly reduces the risk of perinatal transmission, Dr. Raynor commented.

For women receiving antiretroviral treatment during pregnancy at the time of delivery, or both, there is a 1% transmission rate, compared with 9.8% for untreated mothers (J. Infect. Dis. 183[4]:539-45, 2001). Antiretroviral treatment reduces the risk of transmission even in women with viral loads less than 1,000 copies/mL at delivery.

This patient is a good candidate for a scheduled cesarean section, which reduces perinatal transmission among women with unknown viral loads who are not taking antiretroviral therapy for prophylaxis. The American College of Obstetricians and Gynecologists recommends scheduled cesarean section deliveries at 38 weeks to decrease perinatal transmission in women with viral loads greater than 1,000 copies/mL. Intrapartum management includes intravenous zidovudine 3 hours before surgery and antibiotic prophylaxis to prevent endometritis and postpartum infection.