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I know the exact date of my lmp! it was november 17th 2009, which makes my due date August 24th. i just had a ultrasound this week and it showed that i was only 18 weeks instead of 20. is it possible my baby is underweight and that threw off my date? they gave me a new date of Sept 6th 2010! should i go by the ultrasound or my date!? please help !!!


Asked by Anonymous at 2:31 PM on Apr. 9, 2010 in Pregnancy

This question is closed.
Answers (9)
  • Your LMP isn't an exact because ovulation doesn't ALWAY happen EXACTLY 14days afterwards, it can also take up to 72hrs to fertilize the egg, etc. Ultrasounds are just estimates too since once you're out of the 1st trimester babies will all grow differently. I'm more concerned as to why they moved up your due date TWO MONTHS if the ultrasound only showed a TWO WEEK difference. That doesn't sound right to me & I would probably find another doctor to give a second opinion. Anyway, either way, take both dates as a complete estimate....even those that know the exact conception (like with fertility treatments or whatever its called when they put the already made embryo in the womb) it is still a wavering date within a 4week period (two weeks before due date to two weeks after due date). There are also chances of premature labor, emergency situations where induction or csection is needed, etc. The dates are pretty pointless IMO.

    Answer by WannabeMommy87 at 2:53 PM on Apr. 9, 2010

  • Neither your LMP or ultrasound are going to be accurate. But this is not something to be worried about, either. Just keep this in mind so that you don't have an induction that could possibly be done too early.

    Answer by Anonymous at 2:33 PM on Apr. 9, 2010

  • Your due date is an estimated date give or take two weeks. Keep both dates in your mind. You will not be preggo forever and before you know it you will be holding your tiny baby. Stressing over dates will drive you crazy enjoy your pregnancy it a wonderful life experience.


    Answer by Anonymous at 2:36 PM on Apr. 9, 2010

  • They judge the age of your baby from the ultrasound by measuring the femur (the bone in the thigh) but it isn't exact science. When I had one done with my daughter because of complications they judged my due date to be July 3rd. When I had her June 13 she was two weeks over due. And two weeks difference from one another isn't that bad of a difference. On your next appointment say something to the dr about it, but your baby is healthy (unless they say otherwise) and that is worth being happy about!!

    Answer by CrazyKiss at 2:39 PM on Apr. 9, 2010

  • EARLY ultrasound is usually the most accurate method in determining EDD. As you get further along, the baby's measurements can be off by several weeks, and it doesn't necessarily mean anything unless it shows a lack of growth. I was measuring a few weeks behind for most of my second pregnancy, then a couple of weeks ahead for the last month, and I still had my baby on her due date (based on knowing when I ovulated). Don't stress about it, it really doesn't matter. Your baby will come when it's ready, regardless of what date you put on it. But for your own sanity, I'd say go with the later date; that way if you have the baby early, great, but if you don't have it until later you won't feel so bad. :)

    Answer by DragonRiderMD at 2:52 PM on Apr. 9, 2010

  • Most people know the date of their is the OVULATION date that is in question, and even that is inexact because you can get pregnant for a certain amount of time after ovulation (I don't remember exactly) from sex you had up to a day or two before you ovulated.... the previous posters said, due dates are an estimate and plus or minus two weeks is normal!

    Answer by BJoan at 3:12 PM on Apr. 9, 2010

  • Neither, actually. The dates you're given are an estimate.

    Answer by gdiamante at 4:02 PM on Apr. 9, 2010

  • I wouldn't go by either, I would just expect to have a baby between those dates maybe before...maybe after. You can't go by the date of your LMP because they consider you pregnant on that day. Which means the day you found out you were pregnant, the docs considered you already 4 weeks pregnant. When really, you didn't conceive until you ovulated which would have been between 6 and 18 days after your LMP. For instance, my LMP was February 14. I had a doctors appointment on February 26th (we'd been trying for about 6 months and I just wanted to get things checked out to make sure there was nothing wrong) and the ultrasound showed I hadn't even ovulated yet. My doctor said she estimated I'd ovulate in 4-5 days just by looking at my ovaries. My hubby and I both work a lot, and didn't have sex until March 6th. Found out March 15 that I was preggo, and I was considered 4 wks. Even though I couldn't have conceived before

    Answer by Anonymous at 8:27 PM on Apr. 9, 2010

  • Feb. 26th (which would have been normal ovulation for a regular cycle...I ovulate later in my cycle) so my doctor considers me 8 weeks pregnant right now, but really I'm pretty sure I'm only 6. It's difficult math you can't depend on a certain date to have your baby. You just have to prepare for it to come around the estimated times your doctor gives you. Good Luck and Congrats!

    Answer by Anonymous at 8:29 PM on Apr. 9, 2010