SAN FRANCISCO – Giving a rapid HIV test to a woman in labor can help prevent transmission to the newborn, but it's just the first step, Dr. Deborah Cohan said at a meeting on antepartum and intrapartum management sponsored by the University of California, San Francisco.
A recent study of labor-and-delivery suites in Illinois hospitals found that all had rapid HIV tests available but only a small percentage had adequate supplies of intravenous zidovudine (AZT) to give to mothers with positive results. “They were ready, but not quite ready,” said Dr. Cohan.
The key to managing positive rapid HIV tests in labor is to be prepared, she stressed. Health care providers should have easy access to a written protocol and to HIV consultants. The Centers for Disease Control and Prevention's free Perinatal HIV Hotline can provide both and is reachable around the clock at 888-448-8765, said Dr. Cohan, medical director of the Bay Area Perinatal AIDS Center.
Hospital pharmacies should stock adequate supplies of antiretrovirals for use on labor-and-delivery wards–not only AZT in both intravenous and liquid formulations so that both the mother and the baby can be treated, but also oral nevirapine in 200-mg doses. Patient education materials should be handy as well.
When a rapid HIV test reads positive, “Often people think, 'Oh, I need to tell the mother,' but you need to tell the pharmacy first,” Dr. Cohan advised. Alert the pharmacy about the need for antiretroviral therapy and think about the best mode of delivery for this patient. Alert the patient's nurse, and then tell the patient about the positive result and your recommendations for treatment and delivery.
All positive results should be treated as true positives because “there's no way to guess which might be false positives,” she noted. A 66% rate of transmission for an HIV-positive mother to the newborn can be reduced to less than a 10% risk with intrapartum and/or neonatal antiretroviral therapy. “It's probably less than a 5% risk” with therapy, she said. Start maternal antiretroviral therapy, and alert your pediatric colleagues to decide on a neonatal regimen. “The Perinatal Hotline can help with this as well,” Dr. Cohan added.
To minimize risk of vertical transmission, reduce the duration of rupture of membranes or labor, avoid fetal scalp electrodes or fetal scalp sampling, avoid forceps and vacuum deliveries if possible, and avoid an episiotomy if you can, to reduce the baby's exposure to maternal blood.
A cesarean section is indicated if the pregnancy is at 38 weeks' gestation with no ruptured membranes and no labor, and you can initiate maternal antiretroviral therapy before the procedure. Giving antiretrovirals 3-4 hours before C-section allows time for adequate drug levels in the mother and in umbilical cord blood.
If a woman comes in prior to 38 weeks to rule out labor, and she's not in labor and the membranes are intact but a rapid HIV test is positive, consider hospitalizing her to give intravenous antiretroviral therapy and then deliver by C-section at 38 weeks, Dr. Cohan suggested.
“We've had very good luck at getting the viral load substantially lower even after just a few days of antiretrovirals,” she said.
Six rapid HIV tests have been approved that give same-day results. All require confirmatory testing for diagnosis. The rapid tests are useful for women in labor who have had no prenatal care or who did not get an HIV test during their prenatal care. Numerous studies have shown rapid HIV testing in labor is cost-effective, Dr. Cohan said.
It's a good idea to evaluate the prenatal HIV testing rate at your institution, she suggested. At San Francisco General Hospital, where Dr. Cohan practices, “we thought we were doing fine” until a study showed they were testing only 52% of pregnant women for HIV.
The hospital lost its dedicated HIV test counselor because of budget cuts, but incorporating HIV testing into nurses' routine intake procedures actually boosted the prenatal testing rate to 93%.