Oestrogen is one of a woman’s reproductive hormones, produced by the ovaries, and responsible for ovulation. Production of oestrogen is stimulated by the secretion of FSH (follicle stimulating hormone) by the pituitary gland in the brain. Oestrogen production builds during the first half of the fertility cycle, and peaks at ovulation, after which its production declines until a woman has her period, when it begins its cycle again.
The secretion of oestrogen, which begins as the ovaries start to function at puberty, is responsible for the secondary sex characteristics of a woman: the development of breasts, the increase in body fat around the hips, and the beginning of regular menstrual periods. After the menopause, when oestrogen production dramatically declines, not only do women cease to be capable of ovulation and pregnancy, they also lose some of the other benefits of oestrogen, for example, protection of the heart and the strength of the bones.
