If you had had a 7-week ultrasound, and from it worked out that you might have conceived on a given day, I would say you conceived that day.
But since your dating information is from a 17 week 1 day ultrasound, it can't be relied on for that pinpoint of accuracy. The baby could easily be a few days different than the average size by now, either slightly larger or slightly smaller, making the difference between the 18th and the 22nd impossible to judge.
The best you can do is count on the fact that your chances are much better that it is your boyfriend's than that it was from the one-time encounter. Do you still know the other guy well? If so, and if you don't want to tell your ex, have a DNA test done once the baby is born, to put the question to rest. It is the only fair thing to do.
Thats why I got confused , I think its cuhs they go by a 28 day cycle , I was on a 32 cycle , the only that has me concerned is him changing my due date to june 11 , does that mean I concieved before the 22nd ?
How do you get 17 w 6 days now, if you were 17 w 1 day as of the 3rd? That was 8 days ago.
Everything was correct except im actually 17 w 6d and yes it was my first ultrasound . And my last period wasnt sep 4 it was sep 6
Unfortunately, a 17-week ultrasound is not as accurate as an earlier ultrasound, in terms of trying to date a pregnancy. Some embryos grow more quickly than others, and having the doctor adjust your due date as your pregnancy progresses is not uncommon. You should always use your earliest ultrasound for dating estimates, for that reason.
If you simply plug in a due date of June 11 on a conception calculator that doesn't make changes for the length of your cycles, you get:
First Day of Last Menstrual Period: September 4, 2012
Probable Date of Ovulation: September 18, 2012
Possible Dates of Conception: September 14 to September 22, 2012
Due Date: June 11, 2013 (40 weeks)
If your next period would have been due around October 6, that would suggest you ovulated around the 23rd of September. And your boyfriend got lots more chances to be the dad than the other guy. Also, trying to figure this out from an ultrasound measurement of a 17-week baby is not likely to be pinpoint accurate. But because sperm (if any got in) can live for several days in the woman's reproductive tract, if any of the first guy's swimmers made it into your system, it is theoretically possible that they were still there when the egg came down.
Please look at a copy of the ultrasound report and be sure you remember each date and the age of the embryo correctly. If they were not correct as you laid the numbers out above, that might change things in your boyfriend's favor. Was the 17-week ultrasound your first one?
And the ultrasound tech had also said I was 17 w 1 d that day when I went , which also has me confused !
*My bf finished in me everytime we did it