• About Us
    • Contact Us
    • Login
    • ObGFirst
  • COVID-19
  • Alerts
  • OB
  • 2T US Atlas
  • The Genome
  • GYN
    • GYN
    • Sexual Health
  • Primary Care
  • Your Practice
  • #GrandRounds
  • My Bookshelf
  • Now@ObG
  • Media
About Us Contact Us Login ObGFirst
  • COVID-19
  • Alerts
  • OB
  • 2T US Atlas
  • The Genome
  • GYN
    • 0 CME Hours
    • GYN
    • Sexual Health
  • Primary Care
  • Your Practice
  • #GrandRounds
  • My Bookshelf
  • Now@ObG
  • Media
#Grand Rounds

What is the Best Strategy for Fetal Aneuploidy Screening?

image_pdfFavoriteLoadingFavorite

BACKGROUND AND PURPOSE:

  • Multiple strategies for aneuploidy screening are currently being evaluated
  • cfDNA has superior performance characteristics compared to standard first trimester screening (NT + markers) but may miss fetal anatomic/chromosomal anomalies that can be initially detected on ultrasound
  • Kagan et al. (Ultrasound Obstet Gynecol, 2017) compared the performance of first trimester standard combined screening with an approach that uses the combination of a detailed ultrasound exam and cfDNA analysis

METHODS:

  • Prospective randomized control trial of normal first-trimester ultrasound exam at 11 to 13 weeks’ gestation (2015-2016)
  • Subjects were randomized into two groups of assessing aneuploidy risk
    • Standard screening
    • Ultrasound and cfDNA screening if ultrasound is normal
  • Blood was retained for standard serum markers in case the cfDNA result was inconclusive
  • Primary outcome
    • Number of false positives in screening for trisomy 21
    • False positive defined as normal karyotype if risk for trisomy 21 was >1:100, irrespective of the method of risk calculation

RESULTS:

  • 688 women with normal first-trimester ultrasounds were randomized into each group (1) Standard screening cohort and (2) ultrasound + cfDNA cohort
  • All 7 cases of DS were detected on ultrasound based on enlarged NT or fetal anomalies, as were trisomy 13 and 18 cases
  • When comparing risk assessment using standard screening vs ultrasound + cfDNA cohorts, there were no major demographic differences
  • The ultrasound + cfDNA cohort median risk for trisomy 21 was 1 in 10,000
    • None of the cases had a risk above 1:100 [95% CI 0.0 – 0.5%]
  • The standard screening cohort median risk for trisomy 21 was 1 in 3,786
    • > 1:100 risk was identified in 17 (2.5%) pregnancies (95% CI 1.5 – 3.9%)

CONCLUSION:

  • A first-trimester screening for trisomy 21 using ultrasound, NT measurement, and cfDNA in women without ultrasound anomalies is associated with a significant reduction in the false positive rate compared to standard screening
  • This study suggests first trimester serum markers (β-hCG and PAPPA) should not be used
  • By including a detailed ultrasound, disadvantages of cfDNA only testing only are overcome
    • Anatomic assessment provided by ultrasound
    • Saving blood for markers if necessary can address the problem of inconclusive cfDNA results

Learn More – Primary Sources:

First trimester screening based on ultrasound and cfDNA vs. first-trimester combined screening – a randomized controlled study.

image_pdfFavoriteLoadingFavorite

< Previous
All #Grand Rounds Posts
Next >

Related ObG Topics:

Invasive Testing: Are All Centers Seeing a Similar Steep Decline in Procedures?
Practical info on evidence based medicine for your women's healthcare practice
cfDNA vs. Routine Screening – How Do They Compare?
How Accurate is NIPT as a Screening Test for Chromosomal Aneuploidies?
SMFM Guidance – The Role of Prenatal Ultrasound and NIPT 
Down Syndrome / Trisomy 21: Clinical Findings and Prenatal Considerations

Sections

  • COVID-19
  • Alerts
  • OB
  • GYN
    • GYN
    • Sexual Health
  • 2T US Atlas
  • The Genome
  • Primary Care
  • Your Practice
  • #Grand Rounds
  • My Bookshelf
  • Now@ObG
  • Media

ObG Library

  • Hysteroscopy
  • Fertility
  • Site Map/
  • © ObG Project/
  • Terms and Conditions/
  • Privacy/
  • Contact Us/
© ObG Project
SSL Certificate


  • Already an ObGFirst Member?
    Welcome back

    Log In

    Want to sign up?
    Get guideline notifications
    CME Included

    Sign Up

Get Guideline Alerts Direct to Your Phone
Try ObGFirst Free!

Sign In

Lost your password?

Sign Up for ObGFirst and Stay Ahead

  • - Professional guideline notifications
  • - Daily summary of a clinically relevant
    research paper
  • - Includes 1 hour of CME every month

ObGFirst Free Trial

Already a Member of ObGFirst®?

Please log in to ObGFirst to access the 2T US Atlas

Password Trouble?

Not an ObGFirst® Member Yet?

  • - Access 2T US Atlas
  • - Guideline notifications
  • - Daily research paper summaries
  • - And lots more!
ObGFirst Free Trial

Media - Internet

Computer System Requirements

OBG Project CME requires a modern web browser (Internet Explorer 10+, Mozilla Firefox, Apple Safari, Google Chrome, Microsoft Edge). Certain educational activities may require additional software to view multimedia, presentation, or printable versions of their content. These activities will be marked as such and will provide links to the required software. That software may be: Adobe Flash, Apple QuickTime, Adobe Acrobat, Microsoft PowerPoint, Windows Media Player, or Real Networks Real One Player.

Disclosure of Unlabeled Use

This educational activity may contain discussion of published and/or investigational uses of agents that are not indicated by the FDA. The planners of this activity do not recommend the use of any agent outside of the labeled indications.

The opinions expressed in the educational activity are those of the faculty and do not necessarily represent the views of the planners. Please refer to the official prescribing information for each product for discussion of approved indications, contraindications, and warnings.

Disclaimer

Participants have an implied responsibility to use the newly acquired information to enhance patient outcomes and their own professional development. The information
presented in this activity is not meant to serve as a guideline for patient management. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patient’s conditions and possible contraindications and/or dangers in use, review of any applicable manufacturer’s product information, and comparison with recommendations of other authorities.

Jointly provided by

NOT ENOUGH CME HOURS

It appears you don't have enough CME Hours to take this Post-Test. Feel free to buy additional CME hours or upgrade your current CME subscription plan

Subscribe

JOIN OBGFIRST AND GET CME/CE CREDITS

One of the benefits of an ObGFirst subscription is the ability to earn CME/CE credits from the ObG entries you read. Tap the button to learn more about ObGFirst

Learn More
Leaving ObG Website

You are now leaving the ObG website and on your way to PRIORITY at UCSF, an independent website. Therefore, we are not responsible for the content or availability of this site