Oral Concurrent Session 5 - Fetal Genetics and Ultrasound
Oral Concurrent Sessions
Cell-free fetal DNA (cfDNA) based noninvasive prenatal screening is gaining wide adoption as an aneuploidy screening tool. Previous research has predominantly focused on implications of low fetal fraction (FF) and has produced conflicting results relating to the risk of impaired fetal growth and preterm births, but only few studies have examined implications of high FF on adverse pregnancy outcomes. Our aim was to examine the association between high FF and adverse perinatal outcomes in a large prospective cohort.
The SNP-based Microdeletion and Aneuploidy RegisTry (SMART) study enrolled more than 20,000 women across 21 centers on three continents to assess the performance of cfDNA testing with full genetic follow-up. We included cases with a known FF percentage and a sample draw prior to 14 weeks’ gestation. Cases with FF < 5th percentile and those with known aneuploidy or fetal anomaly were excluded. Patients with FF in the upper 25th FF percentile were compared to those with FF between 5th and 75th percentile (controls) for adverse perinatal outcomes. Logistic regression modeling was performed to control for pre-gestational diabetes, hypertension, maternal age, and body mass index.
Of the total 20,887 cohort, 14,831 (71%) were included for analysis. As presented in Table 1, when compared with controls (n=11,060), patients with a high FF in the upper 25th percentile (n=3,771, FF > 12.2%) had a significantly lower incidence of gestational diabetes, preeclampsia, preterm birth (prior to 37th week), and spontaneous loss (miscarriage or fetal demise) but similar risk of abruption and fetal growth restriction. Similar results were observed for the upper 10th, 5th, and 1st percentiles. In multivariate analyses, the results for preeclampsia (OR: 0.73; CI: 0.57-0.95), preterm birth (OR: 0.72; CI: 0.61-0.84), and spontaneous loss (OR: 0.68; CI: 0.46-0.99) remained significant.
In this unselected cohort undergoing cfDNA screening in the first trimester, FF in the upper 25th percentile was associated with a lower risk of adverse pregnancy outcomes.
Sina Haeri, MD, MHSA (he/him/his)
Chief Executive Officer
Park City, Utah, United States
Mary E. Norton, MD (she/her/hers)
Professor, Dept of Obstetrics, Gynecology & Reproductive Sciences
University of California, San Francisco
San Francisco, CA, United States
Bo Jacobsson, Prof.,MD,PhD (he/him/his)
Sahlgrenska University Hospital
Gothenburg, Vastra Gotaland, Sweden
Vivienne Souter, MD (she/her/hers)
Medical Director, Womens Heath
Seattle, Washington, United States
Pe'er Dar, MD
Professor and Director, Division of Fetal Medicine
Montefiore Medical Center/ Albert Einstein College of Medicine
Bronx, NY, United States