The association between fetal fraction and pregnancy-related complications among Chinese population

To examine the association of fetal fraction with a wide spectrum of pregnancy-related complications among Chinese population, we carried out a single-institution retrospective cohort study of women with negative Noninvasive prenatal testing (NIPT) results and singleton pregnancies between May 2018 and May 2020. Indicators of pregnancy-related complications were examined individually, including preterm birth, low birth weight, hypertensive disorders of pregnancy, gestational diabetes, oligohydramnios and intrahepatic cholestasis. We evaluated disease odds ratios (ORs) and 95% confidence intervals (CIs), after controlling for potential confounders including body mass index (BMI), maternal age and gestational week at NIPT. A total of 3534 women were included in our analyses. Women with fetal fraction<15.15% had increased risk of gestational hypertension (OR 4.41, CI [1.65, 12.45]) and oligohydramnios (OR 2.26, CI [1.33, 3.80]) compared to women with fetal fraction≥15.15%. No significant associations with fetal fraction were found for preterm birth, low birth weight, gestational diabetes, and intrahepatic cholestasis. In Summary, fetal fraction is inversely associated with the risk of gestational hypertension and oligohydramnios.