980 Low fetal fraction in IVF pregnancies associated with hypertensive disorders of pregnancy

Abstract

Fetal fraction (FF) from noninvasive prenatal testing (NIPT) has been used as a predictive marker for hypertensive disorders of pregnancy (HDP) in spontaneous pregnancies. We aimed to determine if FF is predictive of HDP in in-vitro fertilization (IVF) pregnancies. Retrospective cohort study of women with singleton pregnancies who underwent IVF with fresh or frozen embryo transfer, had NIPT screening, and had a live birth > 20 weeks at a single institution from 2013-2019. Women with a vanishing twin, aneuploidy, major anomaly, or nonreportable NIPT were excluded. Fetal fraction was corrected for gestational age (GA), platform (MPSS vs SNP-based), and defined as low if <10th percentile. Normal fetal fraction was defined as FF ranging from the 10th- 90th percentile, corrected for GA. The primary outcome was HDP during delivery hospitalization. Multivariable logistic regression analysis was performed to determine the association between FF and HDP, controlling for age, pre-pregnancy body mass index (ppBMI), use of heparin-based anticoagulation, race, ethnicity, NIPT platform, chronic HTN, and pregestational diabetes. 603 women were included, 83 (13.8%) of whom had low FF. Demographic characteristics were similar between groups, although median ppBMI was higher in women with low FF (p<0.001) and chronic HTN was more common among women with low FF (6.0% vs. 2.9%, p=0.043) (Table 1). HDP was more common among women with low FF versus normal FF in univariate analysis (34.9% vs.17.8%, p=0.001). In multivariable regression analysis, the odds of HDP was significantly higher among women with low FF, with an adjusted odds ratio of 2.06 (95% CI 1.15-3.61) (Table 2). Low FF in euploid, non-anomalous pregnancies is associated with HDP in IVF pregnancies. FF has the potential to be used as a predictive marker for hypertensive disorders in IVF pregnancies and may indicate a role for additional preventive and screening strategies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)