count backwards 96 days.
Around Jan1st
32 days previously
just 11wks and 6 days before october18
Subtract fourteen weeks (7 days x 14) from the date of the ultrasound.
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.
May
31st March or thereabouts
never
99% probability it was between 10 weeks & 10 weeks and 4 days ago.
When the doctor counts you as 7 weeks, they are counting from your last period. I figured if the ultrasound says 7 weeks, that is from around sep. 7th, the 1st day of your last period. meaning between sep. 18th thru sep. 24th could have got you pregnant. Likely the 21st. However an ultrasound of 7 weeks on 25th October gives you a due date of 13th June not the 3rd. See the Related Link for "conception-calculator" to the right for more.
Somewhere around December 4.
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.