Down's syndrome screening in multiple pregnancies using alpha-fetoprotein and free beta hCG
Article first published online: 22 NOV 2005
Copyright © 1994 John Wiley & Sons, Ltd.
Volume 14, Issue 7, pages 537–542, July 1994
How to Cite
Spencer, K., Salonen, R. and Muller, F. (1994), Down's syndrome screening in multiple pregnancies using alpha-fetoprotein and free beta hCG. Prenat. Diagn., 14: 537–542. doi: 10.1002/pd.1970140705
- Issue published online: 22 NOV 2005
- Article first published online: 22 NOV 2005
- Manuscript Accepted: 22 NOV 1993
- Manuscript Revised: 14 OCT 1993
- Manuscript Received: 7 JUL 1993
- Down's syndrome;
- prenatal screening;
- free beta hCG
Second-trimester distributions of the free beta human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) levels in 420 twin and 19 triplet pregnancies were measured and compared with the distributions in 6661 singleton pregnancies. On average, the levels of both analytes were twice as high in twins and over three times as high in triplets. Eight sets of twins discordant for Down's syndrome showed elevated levels of free beta hCG and reduced levels of AFP after correction of the multiple of the median for the presence of a twin pregnancy. Screening for Down's syndrome using the twin correction of the multiple of the median is expected to achieve a 51 per cent detection rate at a 5 per cent false-positive rate using these two markers.