What is fetal nuchal translucency?

In the fetus fluid collects behind the neck, much like it does in dependent ankle oedema in later life. This occurs partly because of the fetus's tendency to lie on its back and partly because of the laxity of the skin of the neck. As with ankle oedema this accumulation of fluid can represent the end point of several pathological processes, including heart failure. Fluid collecting behind the neck can be detected as nuchal translucency by ultrasound scanning, and it can be measured. …