To the Editor: Dr Smith-Bindman and colleagues1 concluded that ultrasound screening in the second trimester is not an efficacious screening method for fetal Down syndrome.
Their analysis and conclusions focused primarily on 6 isolated ultrasonographic markers for Down syndrome, and they did not fully consider associated fetal structural malformations, which occur in 28% of fetuses with Down syndrome or multiple markers.2 Table 3 of the article shows that when multiple markers and structural abnormalities are considered together, ultrasound screening has a sensitivity of 69% and a false-positive rate of 8%. The PPVs cited also are underestimated because their prevalence rates for Down syndrome are low. In 1997, there was an overall second-trimester prevalence of Down syndrome in the United States of 1:504. For women aged 35 years or older, the prevalence was 1:134.3 Using these prevalence rates, ultrasound screening had a PPV of 1.68%, that is, 1 in 60 screen-positive women had an affected pregnancy.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 4
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.