First Trimester Risk Assessment Based on Ultrasound and Cell-free DNA vs Combined Screening

"Women randomized in the intervention group will be offered cfDNA screening, along with an early detailed anatomy scan, including nuchal measurement, at 11-13 weeks of gestation. cfDNA analysis will include a simultaneous microarray-based assay of non-polymorphic (chromosomes 13, 18, 21, X and Y) and polymorphic loci to estimate chromosome proportion and fetal fraction. NIPT will be performed at the time of randomization or after if gestational age at randomization \< 9 6/7 weeks of gestation.~Women in both groups will be given oral counseling by obstetricians and will be counseled about test procedures, reporting time, test sensitivity and specificity, and the necessity to confirm abnormal screening results with invasive testing."

Control group includes the standard of care. In our department, first-trimester risk assessment is performed routinely at 11-13 weeks of gestation by FTCS as per standard of care. FTCS includes crown-rump length, NT measurements, and a detailed ultrasound examination based on ISUOG guidelines. All operators who perform this examination are certified by the UK Fetal Medicine Foundation (FMF). A specific risk for aneuploidy is not calculated if NT measurement is \>3.5 mm or if fetal anomaly is identified. These cases are deemed to be at a very high risk for chromosomal abnormalities and are offered invasive testing.