Is Down syndrome screening well understood by women?

January 07 2009

There are specific regulations for Down syndrome screening in France making it obligatory to get women’s written consent. A study carried out by Inserm Unit 912 “Sciences Economiques et sociales, systèmes de santé, sociétés” (Economic and Social Sciences, Health Systems, Societies) and the Poissy-Saint Germain hospital Department of Gynaecology-Obstetrics in the Yvelines département showed, however, that women may poorly understand the various stages of this screening. The researchers found that half the women accepting an ultrasound scan and serum screening were not aware that they might have to make other decisions about whether to undergo amniocentesis or not and, in the case of confirmed diagnosis of Down syndrome, to continue or terminate their pregnancy. These studies are published on line in the last edition of Prenatal Diagnosis.

In France, medical interventions aiming at establishing prenatal diagnosis may only be proposed if they are accompanied by a procedure for informing pregnant women (decree of 6 May 1996). The health professional must certify that he/she provided information to the pregnant mother when this screening was proposed (signature of a certificate by the prescriber) and the prescription must be accompanied by the woman’s written consent for screening.

Down syndrome screening in unborn children usually takes place in two stages: an ultrasound scan during the first trimester of pregnancy, followed by an assay of maternal serum markers associated with Down serum. This blood test has been systematically proposed to pregnant women since 1997; it establishes a global risk of Down syndrome by combining the inherent risk with the mother’s age. Depending on the result, the future mother may be proposed further screening tests by collection of a sample of amniotic fluid or amniocentesis, with a risk of miscarriage in 0.5 to 1% of cases. In the case of confirmed diagnosis of Down syndrome after amniocentesis, the pregnant woman must decide whether or not to continue her pregnancy.

A certain number of studies have been carried out on the efficacy of this type of screening, its cost for society, and about the clarity and understanding of information provided. No study has investigated the way in which women confront the successive decisions that they have to make during Down syndrome screening. In practice, however, women must rapidly make complex decisions.

Are they really aware of the implications of their decisions? To answer this question, Valérie Seror, Head of Research in Inserm unit 912 and Yves Ville, Head of Necker Children’s Hospital department of Obstetrics & Gynaecology analysed, on the basis of a self-report questionnaire, the successive decisions made by 391 women who gave birth in a maternity clinic in the Yvelines between April and October 2005. 88.3% of the women followed the usual screening process, i.e.: ultrasound measurement of nuchal translucency(1) and biochemical screening at the 1st or 2nd trimester.

Study of the questionnaires showed that most women were not aware of, or did not understand the possible implications of Down syndrome screening. Approximately 40% of women who had an ultrasound scan and serum assay were not aware that at a given time they might have to decide whether or not to continue their pregnancy. More than half of them had not thought about the fact that screening might lead to an amniocentesis and approximately one third did not understand the results of the serum assay.

Detailed analysis showed differences in women's involvement in decision-making: women who were passive with regard to decision making, i.e. those who said they were unaware of the implications of screening and who delegated their decision-making to the doctor, were frequently characterised by a poor understanding of their blood screening results.

“Although pregnant women may consider that decisions about the follow-up of their pregnancy should be made by the doctor, it is on the contrary debatable whether or not they should be unaware of the potential implications of screening, in particular the possibility that they may have to decide whether or not to terminate their pregnancy” pointed out Valérie Seror. Whereas the principle of an informed decision is at the centre of the regulations governing Down syndrome screening, the researchers conclude that the idea is not to condemn women’s’ attitudes, but to provide counselling during screening and appropriate information so that women may make their decision in accordance with their own values.

(1) Fluid pocket temporarily present behind the baby's neck which is measured to estimate the risk of Down syndrome.

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"Prenatal screening for Down syndrome: women’s involvement in decision-making and their attitudes to screening"

Prenatal Diagnosis

Researcher contact

Valérie Seror
Unité Inserm 912
232 bld Sainte Marguerite
13273 Marseille cedex9 France
Tel.: 04 91 22 35 02

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