Ultrasound question accuracy

[babycrazy42]

Hey everyone I was just curious as to know if any of you knew your day of conception and if your early ultrasound lined up to it?
I don't temp or anything I'm just curious because I thought I was 7w1d but my ultrasound says diff it reads
8w0d
M1 - 1.58cm
M2 - 1.59cm
M3- 1.60cm crl

Do you think she is accurate

 

[k1w1mum]

My first ultrasound EDD matched perfectly to the EDD off my LMP. When we put these dates into the online calculators to get a conception date, it is out by a week. The date we were given was when my partner was out of town for a week either side! That could have potentially got me in trouble!

 

[babycrazy42]

Lol!! So they are pretty accurate then?!

 

[3Minions]

Early ultrasounds are pretty accurate. Since you don't temp or anything it's possible your lp is shorter than 14 days which could help account for the difference.

 

[babycrazy42]

My periods were usually 26-33 days. Do you think it Would it be a whole week off?! So I should go by the us ?

 

[Yo_Yo]

I've had 8/9 ultrasounds, and they all put me a week ahead of my dates I thought I was.
If it was just one ultrasound, I'd be inclined to suspect it might have been a little out, but not the amount I've had!
They usually go on your ultrasound over your dates, so I think they are generally regarded more accurate. So yes, I'd go by your scan date

 

[3Minions]

I would also go by the ultrasound.

 

[sedgeez]

At my very first ultrasound they put me nearly a week behind what my LMP put me at. All other scans have matched up with the first.

I'd go from the ultrasound.

 

[Claire788]

I had a 6 week and 7 week ultrasound, and it was spot on (I was concrete sure when I OV'd by the time I'd had 12 week scan, they brought my DD forward from 25th to the 21st.. so I'd say the earlier the better for accuracy!

 

[babycrazy42]

that makes me feel a lot better I was freaking out! I had a ton of ewcm the day they are saying I conceived!

 

[3chords]

They're actually not that accurate early on (like under 8-9 weeks) and the margin of error is +/- 5 days.

 

[Mrs Eleflump]

I know exactly what date I ovulated, because of temping.

I had two scans on the same day - by ovulation I was 12+2, and the scans put me at 12+4 and 12+6 respectively. The NT scan said 12+6 so that's what the midwife is going by and they moved my EDD from Oct 7th to Oct 3rd. My ticker is set to the middle date, so by that I'm 23+6 today and due October 5th. By LMP I would have been due September 29th, but I know I ovulated a week 'late', so wasn't worried when baby measured 'behind' based on LMP.

Maybe if I'd had an earlier scan it would have been closer to my dates by ov, and my EDD wouldn't be 4 days out from what I think it should be But baby will come when he/she wants, so it doesn't matter to me what they say my due date is.

 

[Serenyx]

As I just mentioned on your other thread they are fairly accurate but can be a few days out either side. Mine is an IVF pregnancy so obviously we know our dates 100% and I still measured approx 4 days ahead at our 12 week scan. My EDD wasn't changed though as they don't change the dates for IVF pregnancies

 

[babycrazy42]

Thanks everyone reading these make me feel better! Just wanting to make sure it's normal and my baby is ok!

 

[Kitten]

Even if you know when you ovulated, or suspect you do, you don't know how long it took for the egg to travel down the Fallopian tube, the sperm to meet it, and the embryo to attach to the uterine lining. I find most people get frustrated because their dates get moved back a week and they're like "but I only had sex once that month so I know when I conceived" but having sex and conceiving don't happen simultaneously iykwim?