If nuchal translucency screening is combined with first-trimester serum screening the need for fetal karyotyping decreases
Background. This case-control study was performed to evaluate whether adding first-trimester maternal serum testing to nuchal translucency measurement would improve the antenatal detection of Down's syndrome and decrease the number of women offered fetal karyotyping. Methods. In the Swedish Nuchal Translucency Trial 39,572 pregnant women were randomized to a routine scan at 12-14 gestational weeks