My lmp=9/30/13 and lasted until 10/5/13. My cycle length was 35days for that cycle. I had sex on 10/6/2013 and again on the 14th/15th of oct.
Which is more likely the day I had intercourse that lead to conception if my u/s dated me at 11w4days on dec.18,2013?
Additional info: I had pms like symptoms that started oN the 24th of oct. which included sore , tender breasts and cramps worse than pms cramps. This lasted 2-3 weeks. Can you help me figure out which day of intercourse must likely lead to this pregnancy?

My lmp=9/30/13 and lasted until 10/5/13. My cycle length was 35days for that cycle. I had sex on 10/6/2013 and again on the 14th/15th of oct.
Which is more likely the day I had intercourse that lead to conception if my u/s dated me at 11w4days on dec.18,2013?
Additional info: I had pms like symptoms that started oN the 24th of oct. which included sore , tender breasts and cramps worse than pms cramps. This lasted 2-3 weeks. Can you help me figure out which day of intercourse must likely lead to this pregnancy?

They have dated your pregnancy to the start of your last period. Ovualtion usually occurs two or so weeks after that. But the days could be off by though by two weeks ether way so it is virtually impossible to say when conception occurred. If you were early then the first encounter, otherwise the second encounter.

If I had to give odds, I would sayd 49.9% on the sixth and 50.1 on the 14-15th.

Is paternity an issue or is this just a curiosity thing?

It is somewhat an issue . I had intercourse with an x partner on the 6th after we broke up. I had been dating someone else since and my new partner and I had sex on the 14th/15th. So I'm trying to figure it.out and rule out one or the other.

At this point a DNA test after the child is born will be the only way to know for sure, unless there is an obvious distinction between the two. IE one was Asian and the other African.

The problem is that there is about equal chances for either to be the father. Sorry to say but you're going to need to do a DNA test.

At this point a DNA test after the child is born will be the only way to know for sure, unless there is an obvious distinction between the two. IE one was Asian and the other African.

The problem is that there is about equal chances for either to be the father. Sorry to say but you're going to need to do a DNA test.
Thank you!
One more question, how common is it for 30-35day cycles to ovulate the day or week after (from the day ending a cycle) to ovulate? I understand that ovulation with 30-35day cycles occur later than usual?
And how far off can ultrasound dates be?