With pregnancy screening for Down syndrome and other chromosome abnormalities increasingly becoming a routine part of antenatal care, the largest and most comprehensive study to date on Assisted Reproductive Technologies (ART) conceptions in first trimester screening has revealed some worrying statistics. An article published on 6th June 2009, in Human Reproduction*, documents the extent of the problem.
Over 1,700 ART pregnancies and more than 50,000 non-ART pregnancies were tested in the study, conducted in Victoria, Australia. Over the last ten years, second trimester screening for Down syndrome has been progressively replaced by combined screening in the first trimester, between weeks 9-13 of gestation. The aim of the study was therefore to investigate, in a large population-based sample, the effect of ART on the individual markers identified in first trimester screening.
Troublingly, the results of the study reveal that pregnancies conceived using ART show a high rate of false-positive results for Down syndrome.
The implications of these results are potentially tragic. For parents receiving misleading, inaccurate information about the health and wellbeing of their unborn child anxiety, confusion and distress are inevitable. More worryingly, however, we have no statistics about how many of these false-positive results have given rise to misinformed decisions to terminate pregnancies.
Ultimately, this study emphasises a significant disparity between natural fertility processes and new scientific imitations. The high proportion of erroneous results produced by ART pregnancies in first trimester screening underlines the often unknown nature of this new technology, and raises issues regarding the misguided decisions and consequences that parents will inevitably be facing as a result.
*D.J. Amor, J.X. Xu, J.L. Halliday, I. Francis, D.L. Healy, S. Breheny, H.W.G. Baker, and A.M. Jaques.
Pregnancies conceived using assisted reproductive technologies (ART) have low levels of pregnancy-associated plasma protein-A (PAPP-A) leading to a high rate of false-positive results in first trimester screening for Down syndrome. Human Reproduction, Vol.24, No.6 pp. 1330-1338, 2009.