First trimester fetal nuchal translucency: problems with screening the general population. 2.

Objective: To investigate first trimester nuchal translucency > or = 3 mm as a screening test for aneuploidy in the normal pregnant population.

Design: A pilot observational study.

Setting: University College Hospital, London.

Subjects: One thousand one hundred and twenty-seven women had measurements of nuchal translucency at the time of their dating scan (8-13 weeks of gestation).

Results: Seventy fetuses (6%) had a nuchal translucency > or = 3 mm. Five karyotypically abnormal fetuses were identified by standard routine techniques (three trisomy 21, two trisomy 18), all in high risk mothers (> or = 39 years). Only two had nuchal translucency > or = 3 mm (one trisomy 21, one trisomy 18).

Conclusions: Although nuchal translucency measurement is feasible and promising, there is at present insufficient data to warrant its introduction for screening of the general population, or to replace traditional second trimester screening.