Recommendations for the Use of Antiretroviral Drugs During Pregnancy and Interventions to Reduce Perinatal HIV Transmission in the United States

Antepartum Care

Initial Evaluation and Continued Monitoring of HIV During Pregnancy

Viral Load and CD4 Cell Count Testing and Monitoring

Viral loads should be monitored more frequently during pregnancy than in nonpregnant individuals because of the importance of rapid and sustained viral suppression through delivery in preventing perinatal HIV transmission (see Table 5 below). When there is adherence to antiretroviral therapy (ART) and resistance mutations to the prescribed drugs are not present, viral suppression should generally be achieved within 3 to 12 weeks on preferred regimens, such as integrase inhibitor–based ART, depending on the initial viral load.^1-4 Higher viral loads and lower CD4 T lymphocyte (CD4) cell counts are more likely to cause more time to achieve viral suppression^5,6 than lower viral loads and higher CD4 counts. Those using integrase strand transfer inhibitors (INSTIs) are more likely to achieve suppression in much shorter time frames.^7-9 Most patients with adequate viral response at 24 weeks of treatment have had at least a 1 log₁₀ viral load decrease within 1 to 4 weeks after starting therapy.^10,11

Viral load should be monitored during pregnancies impacted by HIV at the initial clinic visit with a review of prior viral load levels, 2 to 4 weeks after initiating or changing ART, monthly until undetectable, and at least every 3 months thereafter. If adherence is a concern, especially during early pregnancy, more frequent monitoring is recommended because of the increased risk of perinatal HIV transmission associated with detectable HIV viremia during pregnancy.^12-14 Similarly, pregnancy may reduce the drug exposure levels or the efficacy of some drugs; patients who are taking these drugs may require a change in therapy or more frequent viral load monitoring (see Table 6 and Table 7). More frequent viral load monitoring is recommended for those who are receiving regimens containing rilpivirine or cobicistat-boosted elvitegravir, atazanavir, or darunavir. Although increasing the frequency of viral load monitoring may help detect viral rebound, this may be difficult to implement if visit attendance or access to viral load monitoring is limited. In addition, viremia detected in late pregnancy may be challenging to manage, requiring medication changes shortly before delivery (see Antiretroviral Therapy Use During Prepregnancy and Early Pregnancy).

Viral load also should be assessed at approximately 36 weeks gestation, or within 4 weeks of planned delivery, to inform decisions about the mode of infant delivery, the need for intrapartum intravenous zidovudine administration, and optimal treatment for newborns (see Intrapartum HIV Care).

For pregnancies impacted by HIV, CD4 count should be measured at the initial clinic visit with a review of prior CD4 counts (see Table 5 below). There is a physiologic decrease in CD4 counts during pregnancy.^15,16 For patients who have been on ART for ≥2 years, have had consistent viral suppression and CD4 counts that are consistently >300 cells/mm³, and are tolerating ART during pregnancy, CD4 count should be monitored only at the initial antenatal visit; CD4 counts do not need to be repeated for these patients during this pregnancy, per the Adult and Adolescent Antiretroviral Guidelines.^10,17,18 Patients who have been on ART for <2 years and have CD4 counts of <300 cells/mm³, those with inconsistent adherence, or those with detectable viral loads should have CD4 counts monitored every 3 months during pregnancy. Patients who have been on ART <2 years and have CD4 counts of ≥300 cells/mm³ should have CD4 counts monitored every 6 months. The safety of this approach is supported by research that demonstrates that patients who are stable on ART (defined as patients who have viral load levels <50 copies/mL and CD4 counts >500 cells/mm³ for at least 1 year) are highly unlikely to experience a CD4 count <350 cells/mm³ in the span of a year.¹⁹

HIV Drug-Resistance Testing

HIV drug–resistance testing should be reviewed in conjunction with ARV history if prior results are available and performed during pregnancies impacted by HIV before starting or modifying ART if HIV RNA levels are above the threshold for standard resistance testing (usually >500 copies/mL to 1,000 copies/mL but may be possible for HIV RNA >200 to ≤500 copies in some laboratories) (see Table 5 below). Genotypic testing should be performed. In cases when there is treatment experience with suspected multidrug resistance and failing regimens are currently being taken, phenotypic testing also should be performed. See Drug-Resistance Testing in the Adult and Adolescent Antiretroviral Guidelines and Antiretroviral Drug Resistance and Resistance Testing in Pregnancy for more information on resistance testing, including considerations regarding INSTI genotypic resistance testing. ART should not be delayed while waiting for resistance test results. If the results demonstrate resistance, then the regimen can be adjusted subsequently. HIV drug–resistance testing also should be performed on patients who are on ART but have suboptimal viral suppression (i.e., failure to achieve undetectable levels of virus during an appropriate time frame, as noted above) or sustained viral rebound to detectable levels after prior viral suppression on ART (see Lack of Viral Suppression While on Antiretroviral Therapy in Pregnancy and Antiretroviral Drug Resistance and Resistance Testing in Pregnancy). Drug-resistance testing in the setting of virologic failure is most useful when it is performed while patients are receiving ARV drugs or within 4 weeks after discontinuing drugs. Even if more than 4 weeks have elapsed since the ARV drugs were discontinued, resistance testing can still provide useful information to guide therapy, although it may not detect all resistance mutations that were selected by previous ARV regimens.

Other Laboratory Testing and Monitoring

The laboratory tests that are assessed initially and used to monitor complications of ARV drugs during pregnancy should be chosen based on what is known about the adverse effects of the drugs a patient is receiving (see Table 5 below). For example, HLA-B*5701 testing should be performed if the use of abacavir is anticipated.^20-24 Routine renal monitoring is recommended for patients who are receiving tenofovir-containing regimens. Liver function should be monitored in all patients who are receiving ART, ideally within 2 to 4 weeks after initiating or changing ARV drugs and approximately every 3 months thereafter or as needed for other clinical care. Hepatic dysfunction has been observed in pregnant women on protease inhibitors (PIs), and the use of any PI during pregnancy has been associated with higher rates of liver function test abnormalities than the rates observed with non-nucleoside reverse transcriptase inhibitor–based ART. Pregnant women in general are more likely than their nonpregnant counterparts to have elevated levels of liver enzymes.^25-27

Pregnancy itself increases the risk of glucose intolerance. In a meta-analysis, the pooled prevalence of gestational diabetes among women with HIV was 4.42% (95% confidence interval, 3.48% to 5.35%). These rates do not appear to be higher than those in non-HIV populations.^28,29 The majority of studies in pregnant women have not demonstrated an association between HIV infection and gestational diabetes.^30-32 However, other studies did show an increased risk of gestational diabetes.^33-‍35 In addition, one study and several case series in nonpregnant adults with HIV have reported an increased risk for incident diabetes after initiation of INSTIs.^36-40 When ART is being taken during a pregnancy impacted by HIV, the standard screening for gestational diabetes that is recommended during all pregnancies should be conducted (see Table 5 below).⁴¹

In addition to gestational diabetes risk, risk for weight gain and obesity both during pregnancy and postpartum may be present with INSTIs, although existing evidence is somewhat inconclusive^42-47 (see Maternal Health Outcomes in Recommendations for the Use of Antiretroviral Drugs During Pregnancy: Overview). Most published data about weight gain associated with specific ARV drugs has been collected in nonpregnant populations (see Considerations for Antiretroviral Use in Special Populations in the Adult and Adolescent Antiretroviral Guidelines and Maternal Health Outcomes in Recommendations for the Use of Antiretroviral Drugs During Pregnancy: Overview). One study in pregnant women with HIV observed higher weight gain with the combined use of tenofovir alafenamide and INSTIs.^48,49 Current guidelines from the American College of Obstetricians and Gynecologists and the National Academy of Medicine recommend that appropriate weight gain, diet, and exercise during pregnancy should be discussed with patients at initial antenatal visits and regularly thereafter.^50-52

References

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