Menstruation, periodic discharge from the vagina of blood, secretions, and disintegrating mucous membrane that had lined the uterus. 1  The biological significance of the process in humans can best be explained by reference to the reproductive function in other mammals.
Chlamydia is a common sexually transmitted disease (STD) caused by infection with Chlamydia trachomatis. It can cause cervicitis in women and urethritis and proctitis in both men and women.
Sometimes, these infections aren't associated with any symptoms but can still cause serious damage to the reproductive system. Common STDs caused by bacterial infections include: 1  Chlamydia is an infection in men and women caused by an organism called Chlamydia trachomatis. Chlamydia is an infection in men and women caused by an organism called Chlamydia trachomatis. 2  Chlamydia increases the risk of pelvic inflammatory disease (PID) in women. 3  Gonorrhea, also known as clap and the drip, is caused by Neisseria gonorrhoeae.