Due date help!

[AlwaysOptimistic2]

Accordingly to NHS, midwife and various website calculators I am 9 weeks 2 days pregnant.

Randomly I have just tried two website calculators working out due date from the ovulation date rather than last day of my period and both say 27 December rather than 24 January making me 13 weeks!

I ovulate quite early in the month and used clear blue every month while TTC so know the date I ovulated.

Does any one know if that sounds right? Only wondering as it might affect when I should have my first scan...quite a big difference!

I wouldn't worry, I had my '12 week' scan but actually measured 9weeks so I went back at 12 weeks.

It's just a rough calculation, they do the same for everyone as some won't know when they ovulated.

That’s definitely possible. Until your 12 week dating scan your due date is unofficially 40 weeks from your LMP but after your scan it will be recalculated - and even though you know when you ovulated, it can still be a little different as it’s based on the baby’s average size.

My cycles are very long so I always calculate based on my ovulation and then use the date two weeks before that as my pretend LMP to work our a rough due date.

Congratulations!

4 weeks difference seems a bit strange given the LMP dating is based on an average cycle length of 28 days (4 weeks). You could well be earlier than the LMP date but are you sure you have the date based on ovulation correct? What date does it give if you assume LMP was 14 days prior to when you know you ovulated?

Thanks all. Was just a little thrown as I didn't even question my due date with my first child. It moved a few times along the pregnancy but he came three weeks early and I'm sure it's because the dates were off. It meant that I had no time off before he was born as I finished on the Friday and had him in the Sunday. Trying to avoid that this time! Maybe I'll just take off January and do some serious batch cooking if I'm wrong

@Weathergirl1 if I put in 14 days before it adds on two weeks to the due date, so 15 weeks.

Have my dating scan in three weeks so unless I get a private scan this week I'll just try to put it out of my head for now. Feeling so much more anxious this time round. Anyway thanks again