29: The effect of maternal heparins and/or aspirin on the amount of cell-free fetal DNA in the maternal circulation

Abstract

OBJECTIVE: Inflammation results in apoptosis in the placenta which causes cell-free fetal DNA to be shed into the maternal circulation. As cell-free fetal DNA testing is extensively used for genetic screening and a sufficient amount of fetal DNA within the maternal circulation is required for test accuracy, it is important to understand if antiinflammatory agents alter the amount of fetal DNA within the maternal circulation. A retrospective cohort study was performed to determine if unfractionated and low-molecular weight heparins and/ or low-dose aspirin, which are thought to decrease placental hypoxia and inflammation in early pregnancy, affect the amount of fetal DNA in the maternal circulation. STUDY DESIGN: A multi-institutional retrospective cohort study was performed using women receiving cell-free fetal DNA testing at the Wake Forest and Indiana University Departments of OB/GYN from January 1, 2014 - June 30, 2016. Data on patient demographics, medical comorbidities, medication use, and fetal fraction of cell-free DNA were gathered. Regression analyses were performed to determine if there were differences in maternal demographics, medical comorbidities, or fetal fraction of cell-free DNA in the maternal circulation in those women that received heparins and/or low-dose aspirin compared to controls. RESULTS: Data from 924 women was gathered. Women on heparins or aspirin (n=65) had higher gravidity, and rates of hypertension and diabetes compared to controls (n=860). Women using heparins and/or aspirin had significantly less fetal fraction (8.4%) compared to controls (12.7%) after adjustment for gestational age at collection, gravidity, and medical comorbidities (p<0.0001). CONCLUSION: Maternal use of heparins and aspirin was associated with a decrease in cell-free fetal DNA in the maternal circulation. Although the mechanism of this change is unclear, it is possible that the decreased placental thrombosis thought to occur with the use of anticoagulants and anti-platelet agents leads to a decrease in hypoxia and inflammation related apoptosis in the placenta, the primary source of fetal DNA within the maternal circulation.