Early scan insight?

[Socksy]

I went for an abdominal u/s today to check for fibroids (history of mid cycle bleeds) and I found out last week I was pregnant. According to OPK tests and temps, I know that I ovulated on the 3rd on Jan - 3 weeks ago today - which should make me exactly 5 weeks pregnant, right? Or is that not how it works?

anyway, via the abdominal u/s she could see the gestational sac but said I was measuring smaller than 5 weeks. Do we think it’s inaccurate because it was abdominal, or does implantation date/time affect gestational age too? As mentioned above, I am certain on my ovulation date being exactly 3 weeks ago today (albeit, it may have been evening of the 3rd Jan) but I’m currently overthinking everything after she said I didn’t look like I was 5 weeks pregnant 😭

any insight/advice greatly appreciated!

🙏

3rd Jan is 3 weeks ago today, so yes, assuming you ovulated around cycle day 14, you would be 5 weeks pregnant. When was the first day of your last period?

It was 18th Dec but I have 31/32 day cycles

I suppose I could have ovulated late on the 3rd (that was the day I had a big temp dip and then rise on the 4th) and perhaps conception actually occurred late on the 3rd/early on the 4th? Sorry my head is going around in circles!

Did she say how far on you were measuring?
There is little difference between 4 and 5 weeks to be honest and we're talking fractions of millimetres difference. Even at 5 weeks there is very little to see - thickening of the uterine walls maybe, an empty gestational sac if you're lucky.

Got this on googling implantation versus gestational age

'Yes, the date and time of implantation can significantly affect gestational age, as a later implantation can lead to a slightly shorter gestational age when calculated based on the last menstrual period (LMP), as the embryo has less time to develop during the early stages of pregnancy; therefore, an ultrasound measurement is often used to more accurately determine gestational age, especially in cases of suspected late implantation'

So until otherwise I would assume you are happily pregnant just a little behind what you thought you were x

Also abdominal often sees less than transvaginal in the really early days x

The OP knows she implanted late, she's calculating from exact ovulation not LMP for that reason

Ovulation isn't the same as implantation......she could of implanted a few days after ovulating..

That’s super reassuring, thank you! No, she didn’t say what she thought I was based on measurements but there was a sac visible and it was only abdominal so that gives me hope 😊

Implantation is what, 6-10 days after fertilisation? So I guess that also leaves a couple of days wiggle room too. My temps don’t really give me an indication of when implantation occurred, just ovulation dip and subsequent rise.

Yes, I'm just explaining why she's not baseing her dates on LMP.

My actual due date and the date LMP would show me as are 10 days difference so LMP won't work if you have longer cycles or ovulated late.

Yes - I know with my two previous pregnancies my dates were always off because of my longer cycles. I had my first 3 days early and my second a week early. Although that would suggest that I would be farther along than I thought? I am petite framed though so I think my body probably just wanted them out earlier!

I know, I was literally answering one of her questions!!

It was a little confusing but clearly well intended