The menstrual cycle is a vital aspect of a woman's reproductive health, encompassing a series of physiological changes aimed at preparing the body for conception. Typically commencing around ages 12 to 15 and continuing until perimenopause, usually around age 52, this cycle occurs every 21 to 35 days, with the average duration being 28 days. Governed by fluctuations in hormone levels, the menstrual cycle involves the thickening of the uterine lining and the release of an egg during ovulation, which marks the peak fertility period calculator for women. If fertilization does not occur, the uterine lining sheds during the subsequent menstrual cycle.