can dates/ultrasound be off by 4weeks?

[DaniJade1990]

This sounds like a very silly question and it probably is but I'm gonna ask anyway! I've had 4 ultrasounds throughout this pregnancy, one saying I was 6weeks, then 8, then one at 13 then one at 20! My lmp was around 23/24 october 09 and I was told I was 6weeks on the 26/11/09! I'm 36 weeks but my bump measures bigger, is there any chance they could of been up to 4weeks late with my dates and I'm actually 40 weeks?
Thanks everyone

They might have been off by a few days or a week at the early scans, but a 13 week scan is pretty accurate - no way would that be off by 4 weeks. If all the scan dates roughly tally, they're probably right. If you ovulated early-ish, you could have been 6 weeks pregnant (or to be more precise, 4 weeks post conception) when they said you were.

Bump size is just an indicator of baby size, not baby age/maturity. My bump was huge but that didn't mean that baby was ready to come out....

I'd go with the 13 week scan dating...

Nope, scan dates would not be off by 4 weeks.

the earlier the scan, the more accurate it is.

bump size is subjective and palpation is not always accurate

there is no way at all your scan dates could be 4 weeks wrong

especially the really early ones..if at your 6 weeks scan you were 10 weeks, tehre would have been a vast difference in what could be viewed.. ditto if at the 13 weeks scan you were 17 weeks.

I had to go backwards and forwards between care for my second pregnancy and on the same day my bump measurement was 2cm different. It really isn't very reliable.