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University of Oxford researchers assessed evidence from 34 studies, involving over 57,000 pregnant women with HIV, and found that protease inhibitor-based antiretroviral therapies significantly increased the risk of babies being small or very small for their gestational age, but there were no other adverse pregnancy outcomes, compared to therapies without protease inhibitors.

Illustration of an HIV virus in the bloodstream

Globally, more than 37 million people were living with HIV in 2020, including 19 million women of childbearing age (UNAIDS). Each year, around 1.3 million of these women become pregnant, most of whom live in sub-Saharan Africa where rates of maternal and child mortality remain high.

Antiretroviral therapy is recommended for all pregnant women living with HIV, since this plays a crucial role in improving maternal health and reducing transmission of HIV from mother to child. However, to date there has been a critical lack of evidence on whether antiretroviral therapies increase the risk of adverse pregnancy outcomes such as preterm birth, low birth weight, stillbirth, and babies being small for their gestational age.*

In particular, there has been concern about a type of antiretroviral drug called protease inhibitors (including atazanavir, lopinavir, and darunavir). Current guidelines recommend that protease inhibitor-based therapies should be used in pregnancy only if ‘first-line’ treatments (such as integrase and reverse-transcriptase based treatments) are either unsuitable or unavailable. These guidelines also often advise against the use of a specific protease inhibitor, lopinavir/ritonavir (LPV/r), citing an increased risk of preterm birth. However, these recommendations are based on limited evidence, and can restrict treatment options for pregnant women with HIV.

To address this knowledge gap, researchers from the National Perinatal Epidemiology Unit (NPEU) at Nuffield Department of Population Health, have conducted the largest review of the evidence on pregnancy outcomes for a range of antiretroviral therapies. This included a comparison of protease inhibitors vs non-protease inhibitor-based antiretroviral therapies and comparisons of different types of protease inhibitors in relation to the risk of 11 specific pregnancy outcomes for women living with HIV.** The analysis included 34 studies conducted between 1980 and 2020, involving over 57,000 pregnant women living with HIV in 22 different countries.

Read the full story on the University of Oxford website