How To Determine The Paternity Of The Fetus?
There is no way to know for sure, but typically women ovulate day 14
Detailed Answer:
Hello and I hope I can help you today. I reviewed your medical history and ultrasound in order to adequately answer your question.
In a typical 28 day menstrual cycle, ovulation usually occurs 14 days before the start of your period. People who have longer cycles ovulate later, and people with shorter cycles ovulate earlier.
Sperm can live up to 5 days in the reproductive tract though, so if your cycle is short, it is possible to be pregnant by Man A, but if you have a typical 28 day cycle the timing favors Man B.
Based on the ultrasound (which is accurate within 5 days) if you are 6 2/7 weeks you conceived around August 17th. It takes a few days for the egg and sperm to travel inside you and find each other, so I would say that man B is the likely father.
I know there is no way to know for sure, but I hope this information was helpful in making your decision.
Best wishes, Dr. Brown
It is even more likely because the ultrasound says you conceived day 17
Detailed Answer:
Again, I can never make any 100% guarantee, but the ultrasound estimates you conceived day 17 (which is possible with how long sperm remain alive inside you) which, with a 31 day cycle, is perfect timing. So I do think that, especially considering the ultrasound result, there is no way that your intercourse on the 7th resulted in this conception.
I wish you the best of luck ongoing with your pregnancy.
Sincerely, Dr. Brown