I don't know my lmp

[Armylife14]

If I don't know my lmp and I had an ultrasound and dr said I was 6W1D is that the day I concieved? Or do they add weeks to it even with it being a measurement?

[AnnieBrooke]

When was the doctor appointment where he said 6w1d?

[Armylife14]

Okay, so here's the thing I had sex with guy a from oct 4-oct19 don't know the exact days just a lot thought thise dates. Started bleeding oct20 but only three days and it wasn't a full period like usual then I had sex with guy b on nov 3 he did pull out. So that's why I'm so worried about the weeks they gave me.   So if he did it by measurement he would still have to add the weeks? Bc I'm hoping it's guy a

[AnnieBrooke]

On the day your doctor did an ultrasound and said you were 6 weeks 1 day, that translates to 4 weeks 1 day since conception.  They do add two weeks, at the front end (before conception) because all medical counts of pregnancy have to be calibrated to the first day of the last period.  Since the average difference between the first day of a period and the ovulation following it is 2 weeks, that is the allowance that they add, even to an ultrasound.  On the day the doc said 6w1d "along" or 6w1d "GA," you were 4w1d since conception.