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.
Chlamydial (kla-MID-ee-al) infections are caused by three species of microorganisms. Chlamydia trachomatis can cause eye or lung infections and can also infect the urinary and genital areas of both men and women. Chlamydia pneumoniae causes infections of the respiratory tract, and Chlamydia psittaci causes an illness, known as parrot fever, that is similar to the flu.
Chlamydia is a sexually transmitted disease (STD) caused by the bacteria Chlamydia trachomatis. C. trachomatis is the most common sexually transmitted bacteria in the United States. Up to 70% of genital infections are associated with few or no symptoms. Women are more likely to be asymptomatic than men (80% vs 50%).