To examine how women use the nuchal translucency (NT) risk adjustment in decision-making for invasive prenatal diagnosis.Study Design
Retrospective cohort study of 1083 consecutive NT screening exams. A screen-positive test was defined as a risk ≥1/300. Primary outcome was what proportion of screen-positive or screen-negative women chose to undergo chorionic villus sampling or amniocentesis.Results
Of the women tested, 79% (858/1083) were ≥35-years-old and 88% (756/858) of these women had a decrease in age-related risk after NT. Of the screen-negative women, 31% (238/756) ≥35 years of age chose to have invasive testing as compared to only 11.2% (25/223) of those <35 years of age (p < 0.001). Of the screen-positive women, 71% (72/102) ≥35 years of age and 100% (2/2) <35 years of age chose to obtain invasive testing (p = 0.368).Conclusion
First-trimester NT screening for Down syndrome (DS) enables a significant number of women over age 35 to lower the risk for DS several fold and avoid the risks of invasive testing. However, despite significant reductions in age-specific mid-trimester DS risks, a relatively high proportion of women ≥35 years of age still opted for invasive testing.