Sometimes after my husband and I make love, I go to use the bathroom because I have to. Does that lower my chances to get pregnant?

F.T.

It's true that women are advised to urinate immediately after sex to avoid bladder infections. However, if you are trying to conceive, my advice is to wait 10 or 20 minutes before getting out of bed. (Urinating before sex may reduce the urge to go afterward.)

The vagina is a rather hostile environment for sperm. The low vaginal pH (acidity) rapidly destroys the sperm's ability to swim and to attach to the egg. When ejaculation occurs, the semen forms a jelly-like clot on the face of the cervix (the entrance to the uterus, located at the end of the vagina). The sperm can then swim out of the clot directly into the cervical mucus, avoiding the vaginal environment. After about 10-20 minutes, the clot starts to liquify. Once the clot has dissolved, the semen can drain out of the vagina. By this time, however, the acids in the vagina have probably destroyed the fertility potential of any sperm remaining there.