What is menstruation ? Menstruation occurs when the lining of the womb (the endometrium) is shed. Subtitles are available in Polish, Urdu, Spanish, Romanian and Mandarin (via link in video). A version without background music can be found here. A full text script can be accessed here. Menstruation (or period ) happens monthly. As the uterus sheds its lining, vaginal bleeding follows. Menstrual blood is made of blood and tissue. Menstruation occurs when the lining of the uterus sheds, turning to blood that flows out of the body. But what’s normal is different for everyone. Learn more. Menstruation , or a period , is when the lining of the uterus sheds and leaves the body as blood. It marks the beginning of a menstrual cycle.
