Heterosexual acquisition and injection drug use are the principal identified modes of HIV infection in women. Asymptomatic HIV infection is associated with a normal pregnancy rate and no increased risk of adverse pregnancy outcomes. There is no evidence that pregnancy causes AIDS progression.
Previously, two-thirds of HIV-positive neonates acquired their infection close to, or during, the time of delivery. Routine HIV screening in pregnancy, including the use of rapid HIV tests in Labor and Delivery units, and the use of antiretroviral drugs has markedly reduced this transmission risk to approximately 2%. In an HIV-positive pregnant woman, a CD4 count, plasma RNA level, and resistance testing (if virus is detectable, and the patient has not already had this) should be obtained at the first prenatal visit. Treatment should not be delayed while waiting for the results of resistance testing. Prior or current antiretroviral use should be reviewed. A woman already taking and tolerating an acceptable antiretroviral regimen does not have to discontinue it in the first trimester. Patients should also be tested for hepatitis C, tuberculosis, toxoplasmosis, and cytomegalovirus.
Women not taking medication should be offered combination antiretroviral therapy (commonly a dual nucleoside reverse transcriptase inhibitor combination and a ritonavir-boosted protease inhibitor) after counseling regarding the potential impact of therapy on both mother and fetus (see Chapter 31-01). Antiretroviral therapy should be offered regardless of viral load and CD4 count. Whether to start in the first or second trimester should be determined on a case-by-case basis, but it should be started as early as reasonably possible. It can be started in the first trimester after explanation of risks and benefits, provided the mother is not experiencing nausea and vomiting. The majority of drugs used to treat HIV/AIDS have thus far proven to be safe in pregnancy with an acceptable risk/benefit ratio. Efavirenz has been linked with a small increase in anomalies (myelomeningocele) and should not be used in the first trimester of pregnancy. However, efavirenz does not need to be discontinued if a virologically suppressed patient becomes pregnant while taking it. Standard of care also includes administration of intravenous zidovudine (2 mg/kg intravenously over 1 hour followed by 1 mg/kg/h intravenously) begun 3 hours before cesarean delivery and continued through the surgery until cord clamping in women whose viral load near delivery is greater than or equal to 1000 copies/mL or unknown. Antiretroviral therapy on the patient’s usual schedule should be continued in labor. Intravenous zidovudine is not required for antiretroviral therapy-compliant women with a suppressed viral load.
The use of prophylactic elective cesarean section at 38 weeks (before the onset of labor or rupture of the membranes) to prevent vertical transmission of HIV infection from mother to fetus has been shown to further reduce the transmission rate. In patients with a viral load of less than 1000 copies/mL, there may be no additional benefit of cesarean delivery, and those women can be offered a vaginal delivery. Amniotomy ...