Antiretroviral drugs for prevention of perinatal transmission of HIV are recommended for all pregnant women, regardless of CD4+ T cell counts and HIV viral load, and will reduce perinatal transmission through a number of mechanisms. Antenatal drug administration decreases maternal HIV viral load in blood and genital secretions. A number of studies have shown that the penetration of antiretroviral drugs into the female genital tract varies for different drugs.
Initiation of antiretroviral therapy
If HIV infection is first diagnosed in pregnancy, consideration should be given to initiating ART as soon as possible. However, after discussion, some women may elect to commence treatment after the first trimester (providing it does not disadvantage her care). Ideally, ART should be commenced before 28 weeks gestation. The goal is to safely reduce the HIV viral load to undetectable levels well before, and during, delivery regardless of maternal stage of HIV disease [30] or HIV viral load. Combination ART regimens are more effective than single-drug regimens in reducing mother-to-child transmission and are the standard of care. Earlier initiation and longer duration of ART are more effective than later initiation and shorter duration because earlier suppression of HIV replication lowers the risk of transmission for the foetus [31]. The use of ART is highly effective, even in women with advanced HIV disease.
Discontinuation of ART during pregnancy should be avoided as an increase in HIV viral load will result in an increased risk of HIV transmission to the foetus and possible decline in immune status of the mother [29]. Pregnancy does not accelerate HIV disease progression, unless the mother already has advanced disease or AIDS.
All antiretroviral-naïve women should have a baseline HIV genotypic drug resistance assay performed. This assay should also be performed for any woman with virological failure during pregnancy requiring a treatment modification, HIV viral load permitting (>1000 HIV RNA copies/mL).
All pregnant women with HIV should also have hepatitis B serology performed and antiretroviral therapy being initiated should also be based on the woman’s hepatitis B status.
Choice of antiretroviral drugs [9, 30]
In general, the same regimens recommended for treatment of non-pregnant adults with HIV infection should be used in pregnant women, with special consideration of existing safety data. However, drug treatment must always be individualised. Consult current guidelines regarding recommendations. [9]
As with all patients, genotypic drug resistance testing is recommended for all pregnant women before initiation of ARVs and for those with a detectable HIV RNA whilst on ARVs. ART initiation should not be delayed pending drug resistance assay results. Always the individualised selection of ARVs need to be based on pre-existing co-morbidities, results of drug resistance assays, known benefits and risks of a regimen in pregnancy and with consideration of the woman’s expressed preference.
For women already on ART, continuation is recommended. There may be concerns about limited experience or limited safety data with newer agents in regard to drug toxicity and teratogenicity and consideration must always be given to known adverse effects for the woman, foetus or infant that outweigh the benefits.
The goals and issues for consideration are the same as in non-pregnant women: potency, durability, preservation of future options, toxicity and tolerability, resistance and, particularly, adherence throughout the whole pregnancy. [9, 30]
The need for strict adherence to prescribed medication throughout the pregnancy should be re-enforced and factors that may adversely affect adherence should be identified and addressed. Treatment modifications during pregnancy should be avoided unless absolutely necessary. Treatment changes undertaken in pregnancy are associated with increased risk of incomplete suppression of HIV replication at the end of pregnancy. [32] Adding a single ARV drug to a virologically failing regimen is not recommended.
It is now recommended that all women continue ART following the delivery of their infant. However several studies have shown that the mother’s adherence to ART may deteriorate in the postpartum period. [33] HIV viral load monitoring has been shown to be valuable in enhancing adherence. [34]