The thing is, sperm are mighty swimmers and swim as happily uphill as downhill. Once they hit that cervical mucus, it's bye-bye vagina entrance and hello uterus. There are a million sperm in a single seminal ejaculation, so if a few of them go out with the semen, enough of the rest do not that you don't need to worry they are all coming out.
I think you might talk to your doc about other things -- tips on timing and frequency, methods of measuring ovulation, and all of that. It might have nothing to do with you being on top. For example, during your fertile window, do not have sex every day, or the sperm count goes down.
In answer to your question, there is always the legendary stand-on-your-head-after-sex approach. You can also have sex while lying on your side (front to front, or his front to your back). A couple in your situation can do some of the more esoteric positions, thanks to the man's legs not being in the way. You might look up a copy of the Kama Sutra or other book on sexual positions.
Positions have no bearing on increased chances of pregnancy, at least there's been no research finding to support this myth. If both of you are otherwise healthy and have no reason to believe there's infertility issues, it's all about timing intercourse within that fertility window. Good luck!!
When I was TTC nurse suggested after ejaculation angle your pelvic up to a 30degree angle w/your bottom down like this \. Another method was doggie style, leaving your pelvic angled downward making sperm not only swim down to your vagina/uterus but no way to go out (gravity). Stay like this for a few min assuring the swimmers find your cave lol. Also, while ejaculating relax your vaginal walls allowing a clearer entrance to your uterus. If your squeezing your blocking their path.
thanks ladies this all helps.
@crystalgodess- when you mean angle my pelvic area up to a 30 degree angle do you mean lay on my back and extend my legs up?? i just wanna make sure i understood you correctly.