to the editor: We appreciated the helpful review of spontaneous vaginal delivery by Drs. Patterson, Winslow, and Matus, especially the inclusion of information about the prevention of perinatal transmission of human immunodeficiency virus (HIV). We agree that antiretroviral therapy should be offered routinely to all pregnant women who are infected with HIV because effective therapy can reduce the risk of transmission from 25 percent to less than 1 percent. However, decisions about mode of delivery (vaginal or cesarean surgery) are dependent on multiple factors and can be complex. We would like to clarify a few points from the article about mode of delivery for women who are infected with HIV.

Guidelines from the Public Health Service Task Force¹ and the American College of Obstetricians and Gynecologists² emphasize that:

1. Decisions regarding cesarean delivery should be made based on maternal HIV RNA level (viral load) at the time of delivery. In practice, this generally means making decisions based on laboratory data obtained at 36 to 37 weeks of gestation.

2. Women with viral loads less than 1,000 copies per mL should deliver vaginally whenever possible. Women in this group have low risk of perinatal HIV transmission (less than 2 percent)^3–5, and there are no data to suggest that cesarean delivery provides any additional benefit.

3. Women with viral loads greater than 1,000 copies per mL should be offered cesarean delivery to reduce the chance of perinatal HIV transmission. The delivery should be performed before the onset of labor and is therefore recommended at 38 weeks of gestation, without confirmation of fetal lung maturity by amniocentesis.

4. It is not known whether cesarean delivery offers any benefit in reducing perinatal HIV transmission once labor has begun or rupture of membranes has occurred. Management must be individualized for women who would have benefited from cesarean delivery, but who present in labor or with ruptured membranes.

Recommendations regarding treatment of pregnant women with HIV infection and their infants can change rapidly and data are lacking in many important areas. The National Perinatal HIV Hotline (1-888-448-8765) provides free, 24-hour clinical consultation for medical professionals caring for pregnant women with HIV infection and their infants. The hotline is staffed by family physicians experienced with HIV-related issues, internists, infectious disease specialists, obstetricians, and clinical pharmacists, and can assist in all areas of perinatal HIV care.