Science behind the length of menstrual bleeding
Everyone’s periods are different, but on average, they last anywhere from 2 to 7 days, and occur every 21 to 35 days (and you can predict when your next period will arrive with our online period calculator).
The menstrual cycle is controlled by hormones. It all starts in the part of the brain called the hypothalamus, which releases gonadotropin-releasing hormone (GRH). This hormone affects the pituitary gland and induces the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Despite the fact that these hormones are released in the brain, they are responsible for the normal functioning of the ovaries. If you thought periods were pretty straightforward — think again!
Under the influence of FSH and LH, the ovaries produce estrogens and progesterone. All these sex hormones can directly affect the production of each other and affect each other through a feedback mechanism, when a large amount of one of them slows down the production of another.
The menstrual cycle consists of several phases linked to fluctuating hormone levels: