Serum screening for Down's syndrome: some women's experiences.

OBJECTIVES--To describe the experiences of a small group of women who had positive results after serum screening for Down''s syndrome. DESIGN--Semistructured telephone interviews and correspondence with women after a positive screening result (four women) negative amniocentesis results (eight), or termination of a pregnancy with a confirmed abnormality (eight). SUBJECTS--20 women who contacted Support After Termination For Abnormality about their experiences of serum screening for Down''s syndrome. MAIN OUTCOME MEASURES--Women''s knowledge and understanding of the test; staff misconceptions; communication of results; how women coped with the diagnostic process; attitudes to the test and to termination of abnormal fetuses. RESULTS--All women were made anxious by their positive screening test, no matter how they were told. The women''s experiences suggested that medical staff were unclear about the implications of screening tests and how to interpret risk. Even after receipt of negative amniocentesis results some women remained anxious. Staff did not always recognise women''s concerns while awaiting amniocentesis results. CONCLUSIONS--The way in which serum screening is being implemented does not always meet the needs of women with positive results. Some of the problems were not specific to screening for Down''s syndrome. When screening tests are introduced policies should be adopted to ensure appropriate support for participants.     

Maternal serum screening for Down's syndrome in early pregnancy.

The possibility of improving the effectiveness of antenatal screening for Down''s syndrome by measuring human chorionic gonadotrophin concentrations in maternal serum during the second trimester to select women for diagnostic amniocentesis was examined. The median maternal serum human chorionic gonadotrophin concentration in 77 pregnancies associated with Down''s syndrome was twice the median concentration in 385 unaffected pregnancies matched for maternal age, gestational age, and duration of storage of the serum sample. Measuring human chorionic gonadotrophin in maternal serum was an effective screening test, giving a lower false positive rate (3%) at a 30% detection rate than that for maternal age (5%) and the two existing serum screening tests, unconjugated oestriol (7%) and alpha fetoprotein (11%). The most effective screening results were obtained with all four variables combined; at the same 30% detection rate the false positive rate declined to 0.5%. The new screening method would detect over 60% of affected pregnancies, more than double that achievable with the same amniocentesis rate in existing programmes (5%), and could reduce the number of children born with Down''s syndrome in the United Kingdom from about 900 a year to about 350 a year.