Topic overview

Start with the big picture

A typical menstrual cycle lasts 21–35 days, with day 1 defined as the onset of bleeding. The follicular phase varies in length and leads to ovulation, followed by a luteal phase that is generally 14 days. Follicle-stimulating hormone supports early follicle growth; changing estradiol feedback contributes to the mid-cycle luteinizing hormone surge and release of the oocyte. After ovulation, the corpus luteum produces progesterone, which supports the endometrium; declining hormone levels precede menstrual shedding. The topic connects this physiology with clinical concerns such as painful or heavy bleeding, amenorrhea, and anovulation, and introduces pharmacologic approaches including NSAIDs, hormonal contraception, and ovulation-induction medicines.