What is the role of the 11- to 14-week ultrasound in women with negative cell-free DNA screening for aneuploidy?

OBJECTIVE: This study aimed to examine the role of the 11- to 14-week ultrasound in women with negative cell-free DNA screening. METHODS: A retrospective cohort study of women at increased risk for aneuploidy based on age or medical history and negative cell-free DNA screening between March 2012 and March 2014 was conducted. Patients were included if they had an 11- to 14-week ultrasound and obstetrical care at our center(s). Primary outcome was an unexpected finding at ultrasound. Imaging findings were compared with obstetrical outcome by medical record review. RESULTS: Study group was composed of 1739 patients. An unexpected finding was identified in 60/1739 (3.5%). An abnormal fetal finding occurred in 37 living fetuses (2.1%); 33 had a nuchal translucency (NT) ≥ 3 mm, including four 'isolated' cystic hygroma and three with a structural abnormality. Four fetuses had a structural anomaly without a thick NT. Karyotype confirmed euploidy in 98.7% of available cases. Pregnancy termination was chosen by 63.6% of those with cystic hygroma or anomaly at the 11- to 14-week scan. Unexpected multiples were identified in 13 (0.7%) women and a fetal demise in 10 (0.6%). CONCLUSION: Unexpected findings at the 11- to 14-week scan occur in 3.5% of patients with negative cell-free DNA. Recognition provides options for comprehensive testing, consultation, and management.