Nae Nae reminded me of something that might be relevant. When ageing a pregnancy, some people describe it from LMP and some people describe it from ovulation, so there are 2 scales you can use. Just wonder if your OB and you are using the same scale? If he is saying it looks like a pregnancy 4 weeks from ovulation, then this would be the same as your 6 week estimate from LMP.

might be worth just checking your talking the same scale.

take care,

kate