gestational age…

[Mrs_k2022]

hello all, just wondering if anyone can clear this up for me…

We had IVF and are now fortunate enough to be exactly 16 weeks pregnant.

We have had our routine scans including dating and the due date we have been given is 3 days earlier than what we calculated. Which is fine I understand that but… the midwife kept saying I was 16+2 … I can’t understand how the age of the foetus can change since we know the exact dates? Not that it really matters I was just interested !

xx

[Solly-44]

Hi,

It’s just that you are measuring 2 days ahead but you’re right, with IVF the dates don’t change. Mine stuck with my IVF due date even though the baby was measuring a full week ahead by 20 weeks, but I’ve heard some midwives are keen to use the scan dates instead! X

[Savvy_teapot]

I had the same thing my consultant said we would be going from the size of the baby on the scans.

[Hidden]

For some reason the NHS algorithm gave a different date to my IVF clinics date (only by a couple of days) so they are insisting on using that date rather than the IVF one which is the correct one (in my mind). I think its to do with this being a donor egg, they didn't quite get their head round that and kept asking me when my last period was!

Our dating scans have always been screwy, like Solly mine has always measured ahead and thats varied between 3 days and over a week (currently a week) but they just go by their original EDD (the wrong one hahaha) x

[Cinderella5]

Oh don't get me started on this we knew exactly how old our boys were due to IVF too and the local hospital still used their own dates....it really got my goat!! Seems like you are in a similar situation ans nobody gave me a straight answer either.🤷🏼‍♀️xx

[Hopeful_dream]

Similar here, I was dated 4 days ahead of my ivf dates at my 12 week scan. I’ve asked about it a few times but they are sticking with their date for my EDD (am now 23 weeks). Although not a big difference, they have said I will likely be induced a week early due to my age which means it’s really 11 days but I know a lot could change as I get nearer that time! xx

[Hidden]

It's frustrating how this can be so different depending on where you live. Thankfully where I am, we've been told what due date the scans estimate, but when I've told the sonographer or midwife the IVF date, they've stuck with that because it's obviously more accurate. This mattered with our first pregnancy because our daughter was 11 days late and I would have been induced if they'd gone with the scan dates instead of the IVF date. Just keep the IVF date in your own mind in case you need that info to make any decisions about your care x

[Riri88]

hi hun,

Crazy isn’t it how it differs per hospital. Mine stuck to my ivf dates as we knew exactly how old the embryo was. While my scans were dating a bit behind.

I think let them do their thing as per hospital trust their ways of working might differ but I would keep in mind your due date based on IVF date as well. Once you get near your due date and they talk about induction or sweeps, take the dates into account. They sometimes seem quite happy to induce early just based on dates which is rubbish as full term can be up to 42 weeks, not 40. If there is a medical reason for induction then of course talk about all the risks and benefits of what they recommend but if it is just because of dates and nothing else, keep in mind the IVF date and it might help to make a decision to go ahead or not. Scans are definitely less accurate and vary greatly. Like we all differ in size and length, so do babies!

[Peony85]

This is something that always bugged me - I think it made me feel that these medical professionals didn’t really get my situation and were following something learned by rote rather than applying any kind of critical thinking skills.

With my first pregnancy, she was measuring a few days bigger but we always stuck with IVF dates. With this pregnancy, he was measuring a whole week ahead at 10 and at 12 weeks but they didn’t change the due date. Our consultant (private) said we know the dates from IVF are accurate so we will use those. But he also said that it makes him comfortable with delivering a bit early (we are having a planned c-section after last time’s unplanned one) as he was comfortable that the development would be in a good place.

My guess is it’s “easier” for them to go by the dates the computer spits out as it will plot the CRL on the mean for that age and so makes it easier to compare everything. But I agree with what others have said that it really matters most at the end if they think you’re further along than you know you are and try to push for an induction sooner than you’d like (happened to a friend of mine).