surely they should err on the side of caution and go with my earlier date, A similar thing happened with my 1st DS and he was born 7 weeks prem, or was he?? This seemed biologically impossible, I accepted their date but in my head I was convinced I was right, I set my heart on my date, and this was a bad idea as it came and went and I was induced 5 days over their predictions (I had a high blood pressure otherwise I would have preferred to go by myself ) So, go figure!! as to letting work know, you can do this , just tell them that the due date is not yet confirmed - it's not likely to change by several months is it?
At 20 weeks scan, they will only change it if out by 14 days.
The factors from you and the babe will denote the birth size enormously, but not in early pregnancy. Hiya, I had a major date difference between my lmp and my dating scan...owing to irregular bleeding which 'must' of been a period but was very different to my actual periods! Because of this I questioned how early you can get a positive result from a 'normal' cheap preg test..to be told sometimes you can get this at 2-3weeks preg.