Ultrasound

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First trimester CRL equation for gestational age

  • 1.  First trimester CRL equation for gestational age

    Posted 05-05-2021 18:34
    Hi all...
    I was wondering what calculation people are using to estimate gestational age based upon CRL.  We are currently using Hadlock 1992 - however are running into some issues with the GA calculation in the 80-84 mm range - as a CRL of 84 mm is generating a GA of 14 2/7 weeks.  This has implications re: GA assignments for NT and subsequent billing (e.g., CRL 84 mm >> 14+ week gestation, which now makes it a 2nd trimester study).  Does anyone know what equation they used when they developed the NT protocols? - since 84 mm is supposed to correlate to 13 6/7 weeks from what we've been told.
    Thanks!

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    Thomas Lee, MD MBA
    SMFM Practice Management Division - Chairperson
    SMFM Clinical Informatics Committee - Ultrasound Subgroup Lead
    Northwest Perinatal Center / Women's Healthcare Associates, LLC - Portland, OR
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  • 2.  RE: First trimester CRL equation for gestational age

    Posted 05-06-2021 22:04
    Hello all,
    We are equally experiencing the same problem at our ultrasound unit and would appreciate if any one with the answer to the problem can share with the group

    Thank you.

    Izuka Rice

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    Izuka Udom-Rice
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  • 3.  RE: First trimester CRL equation for gestational age

    Posted 05-07-2021 19:37
    Try using Kypros Nicolaides CRL graphs, I think they are different than Hadlock.
    There may be some others built into your ultrasound package. I know GE has some different ones.
    I will look at the graphs on Monday when I am back at work to share the others.

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    Kathleen Bradley MD
    MFM
    Private practice
    Westlake Village, CA
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  • 4.  RE: First trimester CRL equation for gestational age

    Posted 05-07-2021 19:43
    https://www.google.com/url?q=https://www.bmus.org/static/uploads/resources/Aug_2009_Fetal_Measurements_D3NApK5.pdf&sa=U&ved=2ahUKEwj2nKHd3rjwAhUDXa0KHYhRCFIQFjAQegQIBhAB&usg=AOvVaw0stV9ha71l0zECH7wB6GKh

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    Kathleen Bradley MD
    MFM
    Private practice
    Westlake Village, CA
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  • 5.  RE: First trimester CRL equation for gestational age

    Posted 05-07-2021 19:45
      |   view attached
    Here is PDF

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    Kathleen Bradley MD
    MFM
    Private practice
    Westlake Village, CA
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    Attachment(s)