Dated 6 days ahead at 10 week scan

[TerrysNo3]

Just wondering if anyone else had experienced this.

I had a scan at what I thought was 5+5 (referred to EPU due to ectopic last year) and baby was measuring 5+6 so assumed my dates were a day out. DH and I are going on holiday long distance on Wednesday so we had another private scan yesterday at what was 9+2 and the baby was measuring 10+1 (3.1cm) - 6 days at this stage seems like a huge difference.

I am fairly certain of my dates as we were TTC and if it were 10+1 then I would have ovulated on CD9 which would be totally random for me, I have very regular cycles.

Anyone had this? If so did your dates get readjusted later?

Thanks :)

Dates from scans before 12 weeks are a bit inaccurate. That's why the "dating" scan is around 12 weeks.

I was changed by 4 weeks when i had my 18 week scan! I was out back to 14 weeks although I was sure of my dates as ex-husband was in the navy and away a lot. When DS was born he was 10lb 4oz and allegedly born at 42 weeks according to their dates.

I have my doubts

I was 6 days ahead at 12 weeks, they kept the dates the same but said they'd check again at 20 weeks.

At 20 weeks, I was 10 days ahead so they booked a growth scan at 36 weeks.

At 36 weeks, they said he was 8lb, and they'd induce at 40 weeks.

I was already waddling, so I went for a nice long walk and he was born that night. 7lb 4oz.

Scans can be up to a week out. They will use the date of your 12 week scan most likely and even if your 20 weeks scan is out (which obviously it might be as there has to be a margin for error), they will probably stick with that.

I was dated 6 days ahead at my 12 week scan. I know pretty much exactly when we conceived as we had been trying for 18 months and I was monitoring everything! The sonographer told me that the dating scan can be out by about 6 days either way
Still not sure how far along to think I am, I am either 18+3 or 17+4 so will be interesting to see what is said at the 20 week scan!
Will let you know OP, but my MW did tell me not to worry about it at all, and to just enjoy the fact I've skipped a week!

I was put forward a week at 12 weeks and know it's impossible as I know when I ovulated. But, until you go overdue it doesn't really matter, then you just have to resist induction if that's what you want.

Interestingly in our private scan all other measurements corresponded with original dates, it was only the length that was a week further ahead (so tall baby) the NHS only go by length compared to average length/ weeks gestation.

Yes, mine changed by 10 days ahead. Like pp said , the dating scan at 12 weeks will give you a more accurate EDD. This can change too and my radiographer at all my scans kept telling me these were a rough guide, as in weight / growth estimations too

Congratulations :)

Thanks all. Its my 3rd DC and I've not had this before, I don't mind too much except I want to make sure I get the nuchal test at the right time and do not get induced as that would muck up my plans for another homebirth. I think I will see what they say at my 12 week scan and then try and persuade them to stick with the latest date possible as I am fairly certain that's right.

I was convinced my due date given at 12 week scan was wrong as I did the maths and knew what I was doing 40 weeks previously (running a marathon, then had a period, then started ttc).
But baby came even sooner than that. I've since discussed it with midwives and doctors, who explained that I must've conceived 'really early in my cycle'... 1st time then!
My son was born 8 months after we started trying, perfect, no developmental problems. .. if anything quite advanced in many ways...
Maybe you conceived early too?

Isn't it just as likely that your baby only had a say, 38 weeks gestation ch? 40 weeks is only an average length

Maybe, but it also ties in with the due date at dating scan (though still early, but as you say, still full term).
I guess I'll never know.