CTN 291-2: Preterm Births in HIV+ Pregnancies

About The Study

This cohort study is investigating the effect of antiretroviral therapy (ART) on pregnant women and their infants through the measurement of markers of placental health. The study is analyzing mitochondrial DNA (mtDNA) in the placenta and other markers in the mother’s blood to estimate the health of the placental cells and to see if these levels affect a mother’s risk of having pregnancy complications, including a pre-term birth. The researchers will also use samples from this study to design an alternative ART regimen that is less damaging to the placenta than current options.

About The Disease

Pre-term birth is one of the major complications related to pregnancy across the world. The cause of pre-term birth is not fully understood but some research suggests that it may be related to impaired placenta function. The risk of pre-term birth in women living with HIV treated with ART is up to three times higher than the risk in women without HIV. Because preterm delivery is a complicated outcome with several possible contributing factors, it is unclear if it is ART, HIV, or a combination of the two that causes the increased risk of pre-term birth.

Although ART reduces the chance of HIV transmission from mother to child from 25% to less than 1%, some ART regimens may have a toxic effect on the cells of the body. Past research suggests that these drugs may impact the function of the mitochondria, an important part of each cell, preventing the placenta from functioning properly and changing hormone levels, leading to an increased risk of pre-term birth.

Study Approach

This study aims to enroll 310 participants in Montreal, Vancouver, and Toronto. Participants will be enrolled from two existing studies taking place in Vancouver and Montreal (CTN 291) and Toronto (led by co-investigator Dr. Lena Serghides). New study participants will also be enrolled: Pregnant women living with HIV will be approached at their first prenatal visit and invited to participate.

The study consists of 3 study visits during pregnancy. Two additional visits will be scheduled during the time of delivery as well as 6 weeks following delivery. Each study visit will take between 30 and 60 minutes. Blood samples will be drawn and swabs will be collected at these visits, along with questionnaires and regular clinical assessments. At the time of delivery, umbilical cord blood and a small piece of cord tissue and placenta will be collected.

The data collected will be analyzed to see if there is a relationship between pre-term birth and the markers collected from the placenta or blood and whether the type of ART regimen used during pregnancy affects this relationship.