Scan dates don’t match conception dates - help!

[ValliBec]

Hello!

I’m having a bit of a panic today about how my pregnancy is professing and would love to hear from anyone who has been through the same thing. I’d been trying to fall pregnant for eight months and finally got my BFP in November. I found out quite early - around 10 days post ovulation. As I’ve got a history of scar tissue I always get scanned early to rule out ectopic pregnancy so my doctor referred me to my local EPU. I told the doctors I was not as far gone as my period dates suggested as I actually ovulated on days 25/26/27 that month and did the deed days 25/26 - I’ve been peeing on those lovely little ovulation sticks for most of this year so I’m well versed in when I ovulate 😃 lo and behold the scan didn’t show much. They said they thought they could see the outline of a gestational sac but called it a pregnancy of an unknown location as they couldn’t be 100% sure. They asked to rescan me today (exactly two weeks later) when according to my conception dates I should be anywhere between 7weeks - 6+5. However, the Sonographer measured me at 5+5 days which is a good week behind where I should be, although with a heartbeat. I know I don’t have my dates wrong as I’ve been diligently tracking ovulation and DTD most of this year (fun hey!?) My question is, has this happened to anyone else?? I’m really panicking that my growth is too slow and I’m headed for a miscarriage (I had one a few years back and scans showed slowing growth before the heartbeat stopped). Also really hoping someone has had the same and it all turned out happily!! 😁 x

I meant progressing not professing! 🤦‍♀️

At this stage, everything is so teeny tiny that dating scans aren't particularly accurate and the sonograoger being just a millimetre or two over or under on their measurements can put you off your dates by a couple of weeks.

With DC2 I had an early scan at what I thought was 9wks exactly and I was only measuring 7w3d. I already had the appointment for my 12wk scan and was told to keep it so three weeks later I went along expecting to be 10w3d but no, I was 12wks. With DC3 I had the same, early scan had me measuring 6w5d and I was paranoid it meant the pregnancy wasn't growing because by my dates I should have been 8wks. Booked my 12wk scan based on the dates of the early scan, 12wk scan had me measuring 13w5d so my original dates were correct. DC1 I had the total opposite issue, went to my 12wk scan and told them I was 11wks by my dates, scan showed I was actually a day off 14wks.

I was like you. I knew exactly when I ovulated but I was put back a week at my 6 week scan. Baby had a growth spurt a few days later and by my 8 week scan he was measuring where I thought he should be. I'm now 21 weeks and all going well.

Try not to worry a heartbeat is a brilliant thing to see X x

I’m 6 days ahead of the date given at an early scan :) (confirmed at 12 week scan)

Early scans aren't always accurate. I had a scan thinking I was 12 weeks, but was only measuring 5 weeks. When I went for what was my 12 week scan I was actually 13 weeks. Try not to stress over the exact date of conception.

Perhaps it’s Because conception isn’t instant? Sperm can live in the body for up to a week (iirc) so even if you DTD on a Saturday you may not “conceive” for a week...

It isn’t an exact science, if you know when you ovulated then the baby will be due approximately 9 months from then.
When I was pregnant with DD2, there was a lady I knew who had been told that her pregnancy wasn’t as far along as she thought from the scan. Except hers was an IVF baby so she knew exactly when fertilisation and implantation had taken place.

All you need to do is a brief scan of the conception board and that will show you that no matter how much you think you know about when you ovulated or how many weeks you are, women are very very often wrong. I knew 100% when i ovulated because I was using ovulation sticks, and temping and doing god knows what else. Despite all this, I'm still due 2 weeks earlier than I should be, and have been ever since the beginning. Every baby grows at different rates so please don't panic until you have a reason to. This forum is falling over itself with posts from woman in the exact same situation as you, and it's very very common for them to then be scanned a few weeks later and have suddenly caught up, or actually have ovulated later than they thought (despite every one of them being convinced they knew exactly when they ovulated).

Good luck and I hope it all works out well for you

Awww thank you so much for all your comments! I’ve been driving myself mad going online trying to see if it’s the norm etc. Its really reassuring to hear this has happened to so many of you and turned out ok - you’ve made me feel much better 😊
I was considering booking an extra private scan just before Christmas to put my mind at ease (well hopefully!) because my Sonographer asked me to go and change my 12 week scan as it was scheduled according to my period dates which are obviously now wildly off! So I won’t have that until the end of Jan which feels a bit of a way off 🥴 oh why can’t I be one of those serene people who takes things as they are and just goes with the flow!? Ha! X

Mine was like this - I had frozen embryo transfers so remember the exact instants a woman doctor impregnated me

Early scans were a few days off with each of them and continued to be a bit off. Had I not had the transfers I wouldn't have been any the wiser.

Thanks @FollowThatStarTonight it’s good to know! 😁

@Quail15 totally forgot to say congratulations on your baby boy! 21 weeks is great, halfway through!! 😊