prenatal screening for downs - syndrome.

摘要

An antenatal screening test for risk of Down's Syndrome in a foetus, which is carried out on a maternal blood sample before the beginning of the third trimester of pregnancy, comprises assaying the sample for a metabolite of feto-placental activity which is affected by the presence of Down's Syndrome, and which may be selected from unconjugated oestriol; progesterone; 16-alpha-hydroxy-dehydroepiandrosterone sulphate (16-alpha-hydroxy-DHEAS); and, dehydroepiandrosterone sulphate (DHEAS). The method may also include an additional assay for alpha-fetoprotein and/or human chorionic gonadotrophin.