Estrogens are a group of hormones primarily responsible for the development and regulation of the female reproductive system and secondary sexual characteristics. They play a crucial role in the menstrual cycle and are produced mainly in the ovaries, but also in smaller amounts by the adrenal glands and fat tissues. In addition to their role in reproduction, estrogens influence various bodily functions, including bone health, cardiovascular function, and mood regulation. There are three main types of estrogens: estradiol, estrone, and estriol, each with specific functions and levels throughout a woman's life, particularly during puberty, pregnancy, and menopause.