Use of Rapid HIV Testing for Women in Labor
Unfortunately, some HIV-infected women present at the time of labor and delivery without having undergone prior HIV testing; behaviors that contributed to their lack of prenatal care, such as substance abuse or mental illness, may also have placed them at increased risk for acquiring HIV. For those women who present at the time of labor without documentation of HIV status, the perinatal guidelines, the Centers for Disease Control and Prevention, and the American College of Obstetrics and Gynecology recommend performing rapid HIV testing in this setting using an opt-out approach (perform testing unless the woman declines).[,,,] Seven rapid HIV tests are now FDA-approved and available for use in the United States: Alere Determine HIV-1/2 Ag/Ab Combo, Clearview COMPLETE HIV-1/2, Clearview STAT-PAK HIV-1/2, OraQuick Advance HIV-1/2, Reveal G3 Rapid HIV-1 Antibody Test, and Uni-Gold Recombigen HIV-1.[,,] In the Mother-Infant Rapid Intervention At Delivery (MIRIAD) study, which involved women in labor with undocumented HIV status, rapid HIV testing was well received, feasible, and performed with greater than 99% sensitivity and specificity. If the rapid test is positive, a confirmatory test should immediately be ordered. In this situation, appropriate antiretroviral prophylaxis should be started, without waiting for the confirmatory HIV antibody test result. The results of the confirmatory HIV test results will then dictate further management.
Antiretroviral Prophylactic Regimens for Women in Labor Not on Antiretroviral Therapy
Because most maternal-to-child HIV transmission occurs shortly before or during labor, HIV-infected women who present in labor with no prior antiretroviral therapy can still derive significant benefit from receiving antiretroviral therapy. In this situation, the HIV-infected pregnant woman should immediately receive a loading dose of intravenous zidovudine (Retrovir) given as a 2 mg/kg loading dose over 1 hour, followed by a maintenance dose of 1 mg/kg/hour until birth. In resource-limited settings, intravenous zidovudine may not be available and studies have shown benefit with several oral regimens for maternal use at the time of delivery, including zidovudine alone, zidovudine plus lamivudine (Epivir), and nevirapine (Viramune).[,,] There are major concerns with given a single dose nevirapine to woman during delivery based on data showing a high rate of non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance in both mother and child after only one dose or two doses of nevirapine.[,,] The development of resistance is thought to result from the long half-life of nevirapine, with significant blood levels detectable for up to 3 weeks after a single dose,[,] resulting essentially in prolonged monotherapy with an agent that has a low genetic barrier to resistance. Development of resistance may affect subsequent response to NNRTI-based regimens given for maternal therapy. In the United States, the perinatal guidelines recommends against administering any medications other than intravenous zidovudine to the HIV-infected pregnant woman during delivery.
Cesarean Section for Women in Labor Not on Antiretroviral Therapy
In this setting of an HIV-infected woman who presents in labor and has not received antenatal combination antiretroviral therapy, cesarean section would theoretically be warranted to reduce HIV transmission since the maternal HIV RNA level presumably would exceed 1,000 copies/ml; in this situation, however, the benefit of cesarean significantly would diminish after the onset of labor or rupture of membranes. If possible, expert consultation regarding cesarean should be obtain in this setting, but given the urgency of the situation, this may not be feasible. A more detailed discussion of the indications for cesarean delivery is discussed in provided in the case Perinatal HIV Transmission and Route of Delivery.
Antiretroviral Prophylaxis for Infants Born to Women Not on Antiretroviral Therapy
All infants born to HIV-infected mother should receive antiretroviral prophylaxis (Figure 1). Infants born to HIV-infected women who did not receive antenatal combination antiretroviral therapy should receive 6 weeks of oral zidovudine combined with three doses of nevirapine (given at birth, 48 hours after birth, and 96 hours after the second dose).[,] The recommendation for this combined regimen in this setting is based on data from the NICHD-HPTN 040-PACTG 1043 study; in this trial, 1,746 formula fed infants born to HIV-infected mothers who did not receive antiretroviral therapy during pregnancy were randomized to receive one of three antiretroviral prophylaxis regimens: (1) a standard 6-week course of zidovudine, (2) 6 weeks of zidovudine in combination with 3 doses of nevirapine given during the first week of life, and (3) 6 weeks of zidovudine combined with a 2-week course of lamivudine and nelfinavir (Viracept). Overall, the rate of HIV infection that occurred during the intrapartum period was 3.2%, including 4.8% in the zidovudine-alone group, 2.2% in the zidovudine plus nevirapine group, and 2.4% in the three drug group; less toxicity was observed in the 2-drug group than in the 3-drug group (Figure 2).
The National Perinatal HIV Hotline
In some circumstances, optimal management of HIV-infected pregnant women and their infants in an attempt to prevent HIV transmission may benefit from expert consultation. The National Perinatal HIV Hotline (888-448-8765) is a federally funded service providing free clinical consultation for medical providers caring for HIV-infected pregnant women and their infants. The perinatal hotline can also assist with referral to local or regional pediatric HIV specialists.