Prenatal screening for fetal abnormalities

摘要

There is disclosed a method for antenatal screening for an abnormality in a fetus using a bodily fluid, the fluid containing a marker which at one stage of gestation (stage A) the mean or median level of the marker differs by less than 20% between pregnancies which are affected and unaffected by the abnormality and at another stage of gestation (stage B) differs by more than 50% between such affected and unaffected pregnancies, there being a period of at least 3 weeks between Stage A and Stage B, characterised in that determinations of concentrations of the marker for an individual woman are made at stage A and at stage B and are compared to produce a normalised concentration and the thus determined normalised concentration is compared with similarly determined normalised concentrations for populations of women with and without said fetal abnormality and an apparatus for carrying out the method.