After sex with my partner, immediately on withdraw sperm flows out, what is the cause and how can be avoided? i have only retroverted uterus.

Normal: Not to worry. This is normal in many cases. I would not be to concerned. Keep a towel handy after sex to wipe with. Your retroverted uterus would have nothing to do with this. Again, very common and I would not be concerned. Hope this helps. Best of luck.

Semen drips out: IT does this in all women. There is no other place for semen and your vaginal fluids to go. This is how nature works. The sperm, however, learn and are programmed to swim to and find the cervix and swim through it. Semen dripping out of the vagina does not in any way lessen the chance of pregnancy.