ObjectiveTo evaluate the association of nuchal septations with chromosomal anomalies during the first trimester of pregnancy.MethodsA total of 281 patients who were diagnosed to have elevated nuchal translucency(NT≥3 mm)or nuchal septations during the first trimester from Jan.2014 to Dec.2016 were included.These patients were divided into three groups:Patients with NT thickness 3-5 mm and without nuchal septations(NT 3-5 mm group, n=124); Patients with NT thickness > 5 mm and without nuchal septations(NT>5 mm group, n=96); patients with nuchal septations(NS group, n=61).ResultsThe rate of chromosomal abnormalities was significantly higher for patients in NS group compared to those in the NT 3-5 mm group(P<0.01)and NT>5 mm group(P<0.01).After controlling for maternal age, maternal BMI, ethnicity and crown-rump length, nuchal septations were reported to be significantly associated with a higher risk of aneuploidy compared with NT 3-5 mm( OR=4.97; 95% CI: 2.76-10.77; P<0.01)and NT>5 mm(OR=3.82; 95% CI: 1.87-7.21; P<0.01).ConclusionsMeasurement of nuchal septations during the first trimester of pregnancy proves to be a useful ultrasound prognostic indicator of chromosomal anomalies.