The changes that occur during the menstrual cycle
Professor Robert Winston describes the journey an ovum takes following ovulation. At about day 14 of the menstrual cycle, the mature egg cell is released from the ovary. This is called ovulation. It then takes around 3 days for the egg cell to travel along the fallopian tube towards the uterus. If the egg is not fertilised, the lining of the uterus begins to break down. This is called menstruation.