The menstrual phase, also known as the menstruation period, marks the beginning of the menstrual cycle for individuals with a female reproductive system. This phase typically lasts around 3 to 7 days, although variations are common. During this time, the uterine lining that built up during the previous cycle in preparation for potential pregnancy is shed. This shedding leads to the release of blood and tissue through the vagina. Hormone levels, specifically estrogen and progesterone, are relatively low during the menstrual phase. Menstruation itself is a visible reminder of the complex interplay between hormones, the uterus, and the entire reproductive system.