Second trimester screening for Down's syndrome: 7 years experience

Citation
Jm. Beaman et Dj. Goldie, Second trimester screening for Down's syndrome: 7 years experience, J MED SCREE, 8(3), 2001, pp. 128-131
Citations number
23
Categorie Soggetti
Envirnomentale Medicine & Public Health
Journal title
JOURNAL OF MEDICAL SCREENING
ISSN journal
09691413 → ACNP
Volume
8
Issue
3
Year of publication
2001
Pages
128 - 131
Database
ISI
SICI code
0969-1413(2001)8:3<128:STSFDS>2.0.ZU;2-N
Abstract
Objectives-To evaluate the effectiveness of the first 7 years of a programm e for second trimester antenatal screening for Down's syndrome, using alpha -fetoprotein (alpha FP) and total human chorionic gonadotropin (hCG) as ma ternal serum markers. Methods-A clinical biochemistry laboratory providing a screening service fo r four obstetric units. Women attending for antenatal care who accepted an offer of serum screening for Down's syndrome were tested between 15 and 20 weeks gestation. Down's risk estimates were calculated using maternal serum alpha FP and total hCG results as modifiers of the maternal age related ri sk. Outcome was determined in collaboration with the regional cytogenetics unit. Results-In 7 years 66 631 women were screened, in whom 108 Down's syndrome pregnancies were identified. Risks for Down's syndrome were reported withou t a specified cut off recommendation; however, at a cut off of 1 in 250, 72 (66.7%) of the affected pregnancies were screen positive, the false positi ve rate was 5.8%, and the uptake of amniocentesis 71.2%. The detection rate was higher in women screened before 17 weeks (70.5%) than in those screene d at 17 weeks or later (56.7% overall and 20.0% in those under 30 years). T he uptake of screening declined gradually from 84% in 1992 to 59.8% in 1998 . Conclusions-Two marker screening using alpha FP and total hCG is an effecti ve way of screening for Down's syndrome and is widely accepted in the local community. Detection rates were comparable with other second trimester stu dies using two markers including both total and free beta hCG.