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Master Thesis

Le dépistage du risque de trisomie 21 : comparaison des méthodes du premier et du deuxième trimestre de la grossesse

Abstract : Screening of the Down's syndrome risk Comparison of the methods of the first and the second trimester of pregnancy. Material and method: The survey, retrospective comparative unicentric, was realized within the maternity hospital of Port-Royal in Paris, between January 2008 and April 2011. Two periods were defined and then compared: before the introduction of the first trimester method, or before September 2009, and after. Pregnant women were all screened by the same laboratory of hormonal biology of Cochin: 1909 women screened during their second trimester and 1417 during their first trimester. Results: There is no statistically significant difference regarding the sensitivity of both screening tests: 70% for the second trimester and 75% for the first trimester (p=0.88). However, the specificity of the first trimester test is better 94% versus 86.4% for the second trimester (p<0.05). This better specificity, without reducing the test's sensitivity, allowed for a reduced number of "at risk" pregnancies, and therefore to decrease significantly the number of diagnostic sampling: 7.1% for the 1st period v. 5.2% for the 2nd period (p<0.05). Despite this result, given that no miscarriage occurred in Port-Royal during our survey, we cannot draw a definitive conclusion regarding the decrease in the rate of induced miscarriage. Eventually, the rate of abortion realized because of Down's syndrome is not significantly different between the 2 periods (p=1). Conclusion: The practice of the Down's syndrome screening method during first trimester in Port-Royal led to a decrease of invasive samplings through a better specificity without a decrease in the sensibility of the test.
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Submitted on : Thursday, July 12, 2012 - 2:47:47 PM
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  • HAL Id : dumas-00717298, version 1


Sophie Brunel. Le dépistage du risque de trisomie 21 : comparaison des méthodes du premier et du deuxième trimestre de la grossesse. Gynécologie et obstétrique. 2012. ⟨dumas-00717298⟩



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