Second-trimester maternal serum screening using alpha-fetoprotein, human chorionic gonadotrophin, and unconjugated oestriol: Experience of a regional programme

Over a 2‐year period from January 1991 to December 1992, second‐trimester maternal serum screening for Down's syndrome using alpha‐fetoprotein (aFP), human chorionic gonadotrophin (hCG), and unconjugated oestriol (uE3) was made available to five health districts in East Anglia, with a total population of 1·2 million. Amniocentesis was offered when the risk of Down's syndrome at term was 1:200 or greater. 25359 singleton pregnancies were screened, representing an uptake of 77 per cent. The recall rate for the 24 per cent of women who had not had a dating scan prior to the test was 9·4 per cent compared with 3·9 per cent for those who had been scanned (P