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Why do i hear that there is a 2week difference in gestational age and fetal age for example if a ultrasound says your 13wks and 5days that means that you baby is only 11wks and 5days old? im confused

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Asked by Anonymous at 6:57 AM on May. 3, 2011 in Pregnancy

Answers (3)
  • me too lol. I have no idea how that works. My doctor at my first app at 8 weeks asked me when my last menstral cycle was I told him November 2nd so then he had me layback so he could do an internal ultrasound and he was looking he said when did you say your last cycle was? I then said November 2nd. He was like are they regular? I said well sense I had my youngest it has been anywhere from 21-31 days. He said that isn't that much off. He said your showing you are fearther along. But then he said well we will just go with the due date August 9th for now which is from the date I told him. But now at 26 weeks I am measuring really big so I have to go back tomorrow for an ultrasound to measure the baby. Makes me wonder if I am actually fearther along

    Answer by mommy5409 at 8:15 AM on May. 3, 2011

  • When they find out your LMP, they add 2 weeks for ovulation. So, you might be told that you are 13 weeks, but, baby only started forming 11 weeks ago. It's really stupid and outdated and should be changed. They also need to do away with "Estimated" due dates and give you a birth month.

    Answer by BradenIsMySon at 8:23 AM on May. 3, 2011

  • Instead of going from the date in which you ovulated, they go from the date of your last period. That's where the 2 weeks difference come from. Generally if you have a 28 day cycle you ovulate about 2 weeks after the day you start your period.

    Answer by amber1330 at 8:43 AM on May. 3, 2011

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