Has anyone else had this happen when having an ultrasound?

Question

we had our first ultrasound toay and the due date from my period was fed 16 but the baby is bigger then that the due date from the size and development is feb 69. i didnt have this with my daughter she was the right size . accourding to my last period i am 14weeks and 5 days according to the size of the baby (10 days differance) I am 16 weeks and 1 dayim confused how  there be that much of a gap and what do i go by the baby or my last period?

Answer 1

I am in the same boat, I had my first ultrasound today, my due date was jan 21st but the baby measured to be due Jan 16.  I'm just going with the 16th because that's based on the baby's development!  

Answer 2

It actually depends on how far along you are when they do the ultrasound.  I had one at 8 weeks to find out how far along I was because I have very irregular periods.  I had another at 18 weeks and they gave a different due date because of size but my obgyn told me that the earliest one is correct since babies grow at different rates once you are a little further along.  By your due date, I'd guess you are probably far enough along to go by your last period (unless of course, you too are irregular).  

Answer 3

I was told by my doctor to go by the ultrasound. My original due date was February 6th, based on my last period, but when they did the ultrasound, it is now January 30th. Either way, it's only a week. Good luck to you!

Answer 4

My dates said my son was due on March 5th, he was born on April 2nd!! The scan dates said he was due March 29th, he was perfectly healthy. Scan dates are more reliable than period dates, no matter how regular you are, you still don't know when you ovulated.

Answer 5

Ultrasounds after 10 weeks are not as accurate and can be "off" by upto two weeks.  In this case, I would go by LMP.  Baby is measuring a little bigger, but thats normal/okay (will happen 50% of the time).  Our baby measured a week ahead at 12 week ultrasound, and decided to come out 10 days before due date.

Answer 6

This happened with me and the baby I am carrying now. I couldn't remember the exact date of my last period but I knew the month they gave me a due date of sept. 20th. When they did the ultrasound I got a due date of august 27th So definitely go by the ultrasound hope this helps

Answer 7

if you find an answer tell me. by my calculations i would be du3 march 21 by the sono i am due march 3..  

Answer 8

Midwives and Drs recommend you go by the scan due date, they dont measure the size of the baby to get the due date, the measure the length of the thigh bone, this gives a fairly accurate idea of how far gestated the baby is.

Answer 9

This happened to me too, there was quite a difference between the dates (8 days) but my midwife said that as my periods were very regular and I was sure of my dates that it was more likely to be the due date worked out from that that was accurate. I guess babies can quite easily come a couple of weeks early or late anyway so you can never be too sure!

Answer 10

For me, it was the opposite . I thought I was 11 weeks when I was only 9 1/2 weeks and there was a difference of 10 days. And my due date was Jan 15th and My son was born Jan 1st. So I believe they were right. I would jus go with that the ultrasound say. COngrats on your pregnancy! Enjoy every minute of it. :D

Answer 11

This has happened to me 2 out of 3 pregnancies. I was actually about 3 weeks  off with both of them. My Dr. told me that I had just ovulated late with my babies, so that is why it differed so much between my LMP and what the ultrasound said.

Answer 12

i thought i was on on 25th jan with baby number 3 but scan said 14 feb and thats the date hosptial and midwife will use i had very irreguullar periods  

Answer 13

last period....every baby is a different size and the earlier an ultasound it done the more accurate it is of judging the due date....I would go by period

Answer 14

the ultrasound is probably the most correct method, especially if it was done in early pregnancy. at least according to my doc when i was pregnant.  My guess is that you don't ovulate when they say your 'supposed' to. therefore, even though you used the period method, your time from conception was actually two weeks off from accurate cause your body doesn't follow the plan.  The other option, if you are a month farther ahead then you thought, was that you had a period after you got pregnant.  this does happen. a friend of mine is four months pregnant and just missed her first period.  good luck, and don't worry so much.  the baby will come when it is ready, and your doctor can help make sure he/she is healthy regardless of how far along you are. Congrats.

Answer 15

i had a similar thing my baby according to my dates was due 27th of august but according to the scan the 17th of july . he was born on the 1st of august weighin 9lb 2 ozs i think he was just a big baby maybe you are having a boy this time who is just big  either way they come when they feel like it good luck with everything x x x

Answer 16

yes its just goes on head size +other measurements  we had are dates for march 26 are hospital said feb 26 ... well he came on Feb 15 and had all the problems that most premmy babies have but with one  difference are son weighed in at 10lb 2 oz ... he was huge... he is now 13 years old 13 stone and 6ft 3 1/2 in so cud just be a big baby ares was