It would be around 8 weeks before the ultrasound date, since you are not actually pregnant for the first two weeks. Pregnancies are dated from your last period. So period on day one, conceive around 14 days after that and therefore '2 weeks pregnant' at that date of conception.
May
31st March or thereabouts
99% probability it was between 10 weeks & 10 weeks and 4 days ago.
just 11wks and 6 days before october18
Doctors measure pregnancy from the first day of your last period, but you don't conceive until two weeks after that. Your baby was conceived 3 weeks ago.
never
The ultrasound date is approximate and based on the size of the baby, but if you go back exactly that far it would be Sept 21.
you conceived somewhere between may 13th to may 18th or about 14 days after your LMP The 7 weeks 3 days is nominally from your LMP if you have a 28 day cycle. See the Related Links for "Pregnancy date calculator" to the bottom for the answer.
At this stage, yes the ultrasound can be off by 10 days. Mine was off by ten days the other way, that is I thought I was 18 weeks and the ultrasound said 16 and a half. I knew when I had conceived because my husband had been away on a trip.
5 weeks and 2 days before that day - give or take a day or two.
This is an estimate based upon size of development. Yes, you could take this to be the date of conception, if more accurate information is not available. However, this would not be conclusive proof. It is an estimate!
April