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, caused by the bacterium Chlamydia trachomatis, is the most common sexually-transmitted bacterial infection in the UK, particularly amongst sexually active men and women aged 16-24 years. In the majority of cases, the disease is asymptomatic in both men and women.