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Ultrasound due date

when you are given a due date based off of ultrasound rather than what your LMP suggests do you count back 38 weeks or 40 to determine when conception may have occured?

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Asked by Anonymous at 7:20 AM on Apr. 21, 2009 in Pregnancy

Answers (5)
  • ultrasounds can be measuing to be 37 weeks and im due tomorrow =P
    i trust the blood work

    Answer by MissKellee at 7:57 AM on Apr. 21, 2009

  • wow. well congrats and good luck :)

    Answer by Anonymous at 7:59 AM on Apr. 21, 2009

  • thankyou ^_^

    Answer by MissKellee at 7:59 AM on Apr. 21, 2009

  • LMP can be just as inaccurate depending on your cycle. Of course the PP is measuring wrong, u/s for size are very inaccurate AFTER the first trimester because genetics play a huge role in development. There isn't much variation in embryo's though.

    If you were given an early dating u/s you would count back what the u/s told you. They don't take off a couple weeks with an early u/s because it's based on size. So for instance if the u/s said you were 7w6d you would count back 7w6d. No need to take off any days or add any etc because your embryo is the size of a 7 week embryo.

    My LMP's are never right. I got an early dating with my daughter and counting back it made much more sense! I know around the time of conception for this one so I didn't need an early u/s. I only got an emergency one at 15 weeks then the 20 we one. I am sure if I got one now I would be measuring ahead. I carry big babies :)

    Answer by celticreverie at 8:41 AM on Apr. 21, 2009

  • not sure.. that would be a good question for your ultrasound tech.. mine was awesome and did a great job answering all my questions.. but good luck anyways! AND CONGRATS!!

    Answer by kristal2146 at 9:40 AM on Apr. 21, 2009

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