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When you get an ultrasound how come they tell you to subtract two weeks for example i got an ultrasound they said i was 11wks and 5days i asked when i conceived they told me probably 9weeks ago?

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Asked by Anonymous at 9:02 PM on May. 22, 2011 in Pregnancy

Answers (6)
  • I never understood it. I just went with the due date they gave me, it was pretty accurate.

    Answer by mompam at 9:06 PM on May. 22, 2011

  • The 40 weeks of pregnancy includes the two weeks between the first day of your last period and when you ovulated and conceived. Baby was not around during those 2 weeks, so that's probably why you were told to subtract them.

    Confusing, isn't it?

    Answer by anng.atlanta at 9:10 PM on May. 22, 2011

  • They measure from the day of your last period. 40 weeks after that day baby is due. Most people ovulate 2 weeks after their period so you are considered two weeks pregnant when you have your period. Weird huh?

    Answer by mommytoJames512 at 9:11 PM on May. 22, 2011

  • They start from the first day of your cycle, even though you don't conceive until ovulation about 2 weeks later. The logic is that it is when the egg begins maturing even though it isn't fertilized yet.

    Answer by Mom-2-3-Girlz at 9:12 PM on May. 22, 2011

  • And because they can not pin point the exact day you conceive ~ which varies from woman to woman and can even vary pregnancy to pregnancy...but they can know the last day you weren't pregnant during that cycle.

    Answer by desert_diva at 9:18 PM on May. 22, 2011

  • Because they date the weeks of pregnancy from the date of your last menstrual period, which in the average cycles is about two weeks before conception. So when you are, for instance, 11 weeks pregnant, that means you are 11 weeks past your last menstrual period and you conceived about 9 weeks ago.

    Answer by Freela at 9:34 PM on May. 22, 2011

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