The ovaries are one part of a female's reproductive system. This reproductive system is made up of the: Vagina Womb or uterus Fallopian tubes Ovaries There are two ovaries, each about 4 centimetres long. They produce one egg each month in a fertile woman, which travels down one of the Fallopian tubes to the uterus. If conception does not occur, the egg is flushed out of the body with the thickened lining from the uterus. (This is called the 'period', or menstruation). The ovaries also produce hormones called estrogen and progesterone. These hormones promote the development of female body characteristics in a girl at puberty, such as breasts, body shape, and body hair. They also control the menstrual cycle and body changes during pregnancy. BACK