Apps say 6 weeks but scan says 4?

[ihavequestions8]

Hi everyone,

I'm 36 and this is my first pregnancy so apologies if I ask any stupid questions

Going by the first day of my last period (29/11/24) my app was saying I was just over 6 weeks, so yesterday I went for an early assurance scan just to check all was ok. Everything went grand, the gestational sac was in the right place and endometrium lining was nice and thick, but I was only measuring 4 weeks so I'm a little earlier than I thought so couldn't see a heartbeat yet or anything like that.

I guess I'm just a bit confused on how far along I am now, I'm guessing it's going by when I ovulated as opposed to the period date and was just wondering jf this has happened to anyone else? The sonographer was really lovely and told me the 2 people in front of me had the exact same thing happen to them, so it's probably just me fretting and overthinking it all.

Many thanks in advance for any responses and apologies again if this is a really stupid question! xx

Hmm... so your calculations are correct. I wonder how good the scanning person is if 3 people in a row aren't measuring correctly for dates, and they are happy to divulge confidential information to other clients. Maybe seek a second opinion?

Who did the scan? Was it a sonographer or a private clinic. Unusual to get such an early scan in the UK unless you have had recurrent m/c. The NHS do the dating scan at 12 weeks and generally go by lmp until that point. Are your periods always regular?

Happened to me but I have extra long cycles and my periods aren't like clockwork. 34 weeks now so it was okay for me but the early scan just caused me so much anxiety🥲

Either your dates are incorrect, which according from last period there not ... you ovulated late or unfortunately it's an early miscarriage and a heartbeat never will develop. That's what the nhs told me when I was referred to the nhs for an empty gestational sac

The first day of your last period is the starting point the midwife and medical professionals use to date your pregnancy but it's not always accurate. It's based on a very average 28 day cycle with ovulation on day 14 so, unless you're physically tracking your ovulation or had ivf or something where you're 100% sure of your dates, it's normal for them to be a little out.

The most accurate measurements are taken at the 12 week 'dating scan' which is when you get your official due date. From this point, LMP is disregarded and the dating from the scan is used.

I am 42 and 30 weeks pregnant, before conceiving, my cycles were really long and irregular so the LMP was never going to be accurate for me.

I had an early scan when LMP would have put me at 8+2 but I only measured 6+1 on the scan so 15 days difference. By my 12 week scan, I'd caught up and was 10 days behind LMP and that's where I've consistently stayed ever since.

Good luck

We paid for a private scan, I've had no symptoms and even though the 10 tests we did over the past 3 weeks all said pregnant I just wanted to see it and then I could actually believe it if that makes sense. I've had no cramping, spotting etc either.

I have another one booked in 3 weeks so praying it shows everything is as it should be and then I can relax a little. I think I've been on google too much and now I've made myself worse!

With my first I thought that I was 8 weeks based on my calculations, but I ended up having an early unit pregnancy scan and they dated me at 6 weeks. My daughter was born at 38+1, so I’m still a little unsure if she came early based on the scan dating, or on time based on my calculations. 😂Either way, she turns 4 years old this month. 🙂Try to relax until your scheduled 12 weeks dating scan - easier said than done I know.

Wishing you and your pregnancy all the best.

@2020N that makes me feel a little better, I'm a natural worrier and this has just skyrocketed my anxiety. Nothing to do now but wait and keep an eye on things but it's good to know others have been in the same situation and everything has been ok. Thank you for the message and congratulations on the safe birth of your wee one x

Do you know when you ovulated?

When was your positive test? If you had a positive 3 weeks ago you’re not going to be only 4 weeks pregnant. Usually even the most sensitive tests won’t pick up a pregnancy until 3 and a bit weeks pregnant.

@nodramaplz I think it was sometime around the 16th December but looking back over my Flo calendar there is no pattern to it and my ovulation test got messed up so tbh I'm not 100% sure?

@Overthebow our first positive test was Monday 30th December which was very faint, we did one of the clear blue electronic ones on the 31st and it said pregnant, 1-2 weeks. Apologies, 3 weeks was a bit of an overstretch, it was only 2.5 in reality (but it's felt like years!)

Okay so you should be minimum 5 and a half weeks. It could be that the measurements were taken inaccurately, it’s the case of mms at this stage so very easy to get wrong or just be hard to read as it’s so small.