Meds May Impact Prenatal Screening in HIV+ Patients

SAN DIEGO -- Pregnant women with HIV taking integrase inhibitors at the time of their non-invasive prenatal screening test had a lower mean fetal fraction than those who were not taking the medication, a small study found here.

HIV-positive patients receiving integrase inhibitors had a significantly lower fetal fraction, or the amount of fetal DNA circulating in maternal plasma, compared to patients without integrase inhibitors (6.18 versus 12.87, P=0.006), reported Aleha Aziz, MD, of Montefiore Medical Center, and colleagues.

At a presentation of the American College of Obstetricians and Gynecologists' annual conference, Aziz said that non-invasive prenatal screening has not yet been studied in HIV-positive pregnant women.

"Integrase inhibitor use is increasing due to their tolerability and potency, making studies like this more significant," she added.

Researchers initially examined data from 20 HIV-positive pregnant women compared to 40 HIV-negative pregnant women undergoing non-invasive prenatal screening in a 2:1 case-control study. Immune status and antiretroviral medications were evaluated in correlation with fetal fraction among patients living with HIV.

Patients were a mean age of 30 to 31 years and there were no significant between-group differences observed in demographic characteristics, including BMI and ethnicity. Overall, HIV-positive patients had a higher mean fetal fraction than HIV-negative patients, but the difference was non-significant (9.19 versus 8.24, P=0.51).

Among patients living with HIV, those who were taking integrase inhibitors at their first prenatal visit had a significantly lower mean fetal fraction compared to patients who were not on the medication (5.5 versus 12.21, respectively, P=0.01).

However, there was no significant difference observed in mean fetal fraction among patients who were taking protease inhibitors either at the first prenatal visit or during non-invasive prenatal screening compared to those who were not.

Immune status may also play a role in fetal fraction among patients on integrase inhibitors, the authors said. Patients on integrase inhibitors with an undetectable viral load at non-invasive prenatal screening had a lower median fetal fraction compared to those with a detectable viral load, but the difference was non-significant (6.5 versus 11.8, respectively, P=0.28).

Patients on integrase inhibitors had a significantly lower viral load at their first prenatal visit and at non-invasive prenatal screening than those patients not taking the medication and there were significantly more patients on integrase inhibitors with an undetectable viral load.

Asked for her opinion, Joanne Stone, MD, director of maternal fetal health at Mount Sinai Health System in New York, characterized these results as "really important" because it shows that non-invasive prenatal screening may not be as effective a screening tool in this population, but that more research is needed.

"We might be counseling patients who are HIV-positive and taking integrase inhibitors that they might not get results from screening," she told MedPage Today. "This needs to be studied more, and more women who are HIV positive that are doing well on medication and getting pregnant."

Aziz said at the presentation that they would like to expand the study population so they could look at a logistic regression analysis between integrase and non-integrase inhibitor users with variables such as BMI, gestational age, and viral load.

She added that it would also be important to look at the interaction of other medical conditions and medications with non-invasive prenatal screening and its effect on fetal fraction.