Early scan dating

[Wonderfun]

I had to have an early scan after discovering I was pregnant and the sonographer said I was 5/6 weeks, later said 6 weeks. Saw heartbeat. However, I know I had implantation bleeding in very early Feb and conceived around 22 Jan. Which would make me over 7 weeks. I said this to the sonographer who just dismissed this and said lots of reasons like late ovulation can make dates out from what you think. The implantation bleeding starting gives me a good idea of when implantation took place though so I'm a bit worried about slow growth. Has anyone else had a similar experience?

Hi, I had an early scan at what I knew was 8 weeks (based purely on the fact I’d only had sex once that month!) but I was measured at just 7 (so a whole week out) I was a bit worried but my OB reassured me it didn’t mean anything.

I went for my 12 week scan a few days ago and have caught up that ‘lost’ week and actually gained a few more days on top of that.

My OB explained it to me as the baby is so tiny in those early weeks, that getting an accurate measurement is quite tricky and a mm can make all the difference.

Best of luck - seeing the HB is a very promising start.

Implantation bleeding doesn't really mean anything in terms of dates.
It could've been anything but it can occur all the way up to 7 weeks pregnant.

It is possible for you to catch up.
However, even if you had sex on a certain date, doesn't mean that's the day it was conceived. Could've been anywhere up to a week later

Dates are really tricky that early. Implantation isn't the only reason you might have a small bleed, ovulation can always be out by a day or so and measurements are imprecise meaning you could have your dates a bit wrong and they could have your measurements a bit wrong giving a pretty wide range - easy to be a week out. If you go searching you will find positive and negative stories as it's really early and hard to know when dates are "off". Possible slow growth can be a concern but seeing a heartbeat is always a good sign. I know that's really hard but there is genuinely nothing anyone can do and most pregnancies are successful.

Thanks for your replies. Makes sense :-)