Whats more accurate to date from LMP or Ovulation day ?

[Mum23boys]

Just wondered which is more likly to give a realistic due date / Anyone got any thoughts ?

[Pangea]

Ovulation day is more accurate. I had long cycles conceiving my boys, I was temping with both of them. I would have thought I was more than a week further along if I had gone my my LMP date. Even though I knew the date I ovulated they both measured slightly less at the scan, DS1 measured 3 days less and DS2 1 day less.

[Wanting-a-girl]

O day was more accurate for me... It was spot on with early u/s

[rainbowflower]

definitely ovulation day
the LMP date just assumes an average 28 day cycle with ovulation on day 14, which obviously isn't how everyone's cycle is

[nuthinbutpink]

O date but the MD will likely go by LMP and then baby's measurement to adjust.

[Mum23boys]

Thanks ladies that would make me 6+5 / 6+6 not 7+1 then which gives me a bit more hope as to why they didnt see the second heart beat - i just hope to god next week things turn around and i get seen again and there are 2 beats not 1 - im not sure i can wait until January

[Pangea]

I think at only 6+5 there's a good chance that it's too early.

I was just thinking back there, and it was actually 5 days less that DS1 measured at the scan. Even though I know the date I ovulated, I temped and used opk's and I would have got a BFP at an impossibly early date if their scan dates were right, so he must have just developed slower than average.

So you could have one twin that's possibly developing a little slower than the other.

Did they measure the babies at the scan?

[lovemy4]

Ovulation date would be more accurate but with twins they also could have implanted at different times as well (I think possibly up to 2 days difference). I hope all looks well with both at your next scan!

[You&MePlus3]

Mine was a whole 10 days difference! I know when I concieved and I O'd major late (like only 4 days before period was due that month). She actually went by conception date instead of LMP and the babe measured perfect to the day. If you are a few days off, that could make a difference. Good luck to you. I can't imagine having seen a second sac and having to wait to find anything out.

[rainbowflower]

implantation dates shouldn't affect baby's size as the egg will continue to double at regular intervals whether or not it has implanted... it's mainly errors in measuring or a slightly better/worse angle on the scan that can affect dates