which do you think is the more likely time of conception?

i had a period on 8/25 thru 8/29 and had sex 9/3 thru 9/8 everyday my fertile days were 9/5 thru 9/10 and my ovulation day was 9/8
then i had a period 9/22 thru 9/27 and had sex once after 9/8 on 10/4 and my fertile days were 10/3 thru 10/8 and my ovulation day was 10/6
on my first ultrasound the tech saw the heartbeat which was 11/4, and told me that i had to be pregnant when i had my last period on 9/22 thru 9/27. my question is is it more likely that i conceived when i ovulated and had sex in sept or in oct? its a dif of about 3 weeks in the due date, which i know is not a long time but i keep up with pregnancy calendar and what to expect for myself and the baby and those 3 weeks do make a lot of dif in those aspects. what is your opinion?

It’s possible to have what look like periods during pregnancy, especially at the beginning. Google “decidual bleeding”.

If the US tech is using the measurement and the presence of heartbeat to determine conception date, he’s probably right. The first dozen weeks, the embryo grows at a erlatively predictable rate and so the size will give you conception date within a few days or so, depending on how far along you are. It certainly won’t be off by 3 or 4 weeks in 8 or so.

Congrats and good luck!