Treatment with a protease inhibitor during the first trimester of pregnancy increases the risk of pre-term birth
Further evidence has emerged from research in the United States that antiretroviral therapy based on a protease inhibitor (PI) during the first three months of pregnancy is associated with an increased risk of pre-term delivery. The study is published in the advance, online edition of the Journal of Infectious Diseases.
“We found that PI-based combination regimen use in the first trimester was associated with both total and spontaneous preterm birth risk,” write the investigators. “HIV disease progression or effects of combination ARV [antiretroviral therapy] on the immune system among women with indications for initiation of therapy before pregnancy may contribute to increasing preterm birth risk.”
Appropriate use of antiretroviral treatment during pregnancy can reduce the risk of mother-to-child transmission of HIV to below 1% and combination antiretroviral therapy is recommended for all HIV-positive pregnant women who are ill because of HIV or who have a CD4 cell count below 350 cells/mm3.
Treatment has undoubted benefits, reducing the risk of transmission and protecting the health of the mother. However, its risks are less certain. Research conducted in Europe – but not the US – showed that combination HIV therapy during pregnancy increases the risk of pre-term delivery, especially if it is based on a protease inhibitor. The overall findings of a meta-analysis of 14 studies showed treatment during pregnancy did not increase the risk of premature delivery. Nevertheless, it also found that treatment with a protease inhibitor during the first trimester was a risk factor for premature delivery.
Given this uncertainty, investigators from the US Pediatric HIV/AIDS Cohort Study (PHACS) wanted to establish a clearer understanding of the risks associated with protease inhibitor therapy during pregnancy. They therefore looked at maternal use of antiretroviral therapy among women enrolled in the Surveillance Monitoring for Antiretroviral Therapy Toxicities (SMARTT) study and its association with pre-term delivery and birth weight.
“The large size of the study, which includes detailed information on the specific type and timing of ARV drug