Fetal Fraction of Cell‐Free DNA and Its Interaction With Maternal Pre‐Pregnancy Body Mass Index on Multiple Adverse Pregnancy Outcomes

OBJECTIVE: To investigate the relationships between fetal fraction (FF) and multiple adverse pregnancy outcomes and assess its interaction with maternal pre-pregnancy body mass index (BMI). METHODS: ) on adverse pregnancy outcomes was examined on both multiplicative and additive scales. RESULTS: Continuous FF was inversely associated with GDM, HDP, SVN, PTB, LBW, and SGA. Binary low FF was associated with increased risks of HDP, SVN, PTB, and LBW. Additive interaction was observed between low FF and high BMI on HDP (RERI = 2.67, 95% CI: 1.26-4.32; AP = 0.45, 95% CI: 0.24-0.60). CONCLUSIONS: In early pregnancy, lower FF is associated with increased risk of multiple adverse pregnancy outcomes, particularly HDP, SVN, PTB, and LBW. Besides, the effect of low FF on HDP risk may be amplified among women with high BMI.