The process of menstruation in women takes place every month, with different cycles. Menstruation occurs due to the thickening of the uterine lining which is prepared for pregnancy. In addition to blood, menstrual fluid also contains mucus and lining cells in the uterus. Menstrual cycles occur for 28 days, counting from the first day of the current menstrual period to the first day of the next menstrual period. Even so, not all women have the same menstrual cycle length. This cycle can sometimes come sooner or even later, depending on the conditions of each. Understanding the Menstrual Phases The menstrual process is divided into four phases, namely: Menstrual phase In this phase, the inner lining of the uterus (endometrium), which contains blood, cells of the uterine wall, and mucus, will decay and pass through the vagina. This phase starts from the first day of the menstrual cycle and can last for 4 to 6 days. In this phase, women will usually feel pain in the lower abdom