Dating scan showing different dates

[Ann73]

Hello ladies, I am new to this website and to being pregnant! This is my first preganncy. I was hoping you might be able to give me some advice. I went for my first scan today, believing I was about 7w&4d. My scan came back at 6w&5d - so 6 days less than what I thought. The thing is, my hubby and I only "did the deed" twice in January, on the 20th & 22nd. For the scan dates to be correct, I would have to have conceived on the 27th, which seems late for both out bedding times and my ovulation. It would mean I ovulated on day 26/27 of a usual 35-36 day cycle.

I guess my question is, has anyone else had early dating scans end up being incorrect? Or has anyone else been told they are at least 6 days less pregnant than they thought, but been pretty sure of their conception dates, but gone ahead to have a normal pregnancy?

The heartbeat was good @ 137bpm.

Any advice would help.

Thanks ladies!

[iamLilysmummy]

the dates always change espesially in the early days, i was total 6 different ones,, i stuck to the first one i got which was 30/07/2007 and i had my daughter 31/07/2007.. day later, n i was told 26 of august,lol, aslong as ur baby is growing, its fine,,

:):) good luck xx

[Miss_Vicki]

sperm can live for up to 5 days , so maybe the swimmers lasted till the 27th ?

[justmum]

Don't worry too much about it. I said I was due on 25/5 on dates and my obs said no 31/5 because of your dating scan.

Who was right? Check my sig! :D:D

ETA yes he was just fine.

[Ann73]

Thanks guys, I really appreciate your responses. They have helped put my mind at ease.:hugs:

[delirium]

Ultrasounds are never 100% spot on. They are meant to be more accurate in the early months, thus why they do dating scans early on, but they can be a few days off. with our DS, we only BDed one in the month :o so I know exactly the date of conception. They were about a week+ out too. he was delivered at 38 weeks, but even the mws commented he seemed a bit premmie, more like a 36 weeker.

[leannelizzy]

The ultrasounds calculate dates based on the size of the baby so if your baby is smaller or larger than "normal" you can get a different date.

With Lachlan I had the following:
My dates US dates
10w4d 10w2d +/- 0w5d
12w4d 12w0d
18w5d 19w5d
23w5d 24w0d +/- 2w0d
30w5d 33w0d +/- 2w4d

As you can see the two dates change all the time and the error can be greater later in the pregnancy.

I'm sure you have nothing to worry about.

Leanne