- Estrogens are hormones that are important for sexual and reproductive development, mainly in women. They are also referred to as female sex hormones. The term “estrogen” refers to all of the chemically similar hormones in this group, which are estrone, estradiol (primary in women of reproductive age) and estriol.
- In women, estrogen is produced mainly in the ovaries, but it is also produced by fat cells and the adrenal gland. Estrogen is involved in the onset of puberty, playing a role in the development of so-called secondary sex characteristics, such as breasts, and pubic and armpit hair.
- Estrogen also helps regulate the menstrual cycle, controlling the growth of the uterine lining during the first part of the cycle. If the woman’s egg is not fertilized, estrogen levels decrease sharply and menstruation begins. If the egg is fertilized, estrogen works with progesterone, another hormone, to stop ovulation during pregnancy.
- Estrogen controls lactation and other changes in the breasts, including at adolescence and during pregnancy.
- During pregnancy, the placenta produces estrogen, specifically the hormone estriol.
- Estrogen is instrumental in bone formation, working with vitamin D, calcium and other hormones to effectively break down and rebuild bones according to the body’s natural processes. As estrogen levels start to decline in middle age, the process of rebuilding bones slows, with postmenopausal women eventually breaking down more bone than they produce. This is why postmenopausal women are four times more likely to suffer from osteoporosis than men, according to the Cleveland Clinic.
- Estrogen also plays a role in blood clotting, maintaining the strength and thickness of the vaginal wall and the urethral lining, vaginal lubrication and a host of other bodily functions. It affects skin, hair, mucous membranes and the pelvic muscles, according to Johns Hopkins Medicine. The hormone also affects the brain, and studies also show that chronically low estrogen levels are linked with a reduced mood.
- Men produce estrogen as well, but at lower levels than women. In men, estrogen is thought to affect sperm count.
Source: Rettner, Rachael; Livescience – web article, July 18, 2014, www.livescience.com/38324-what-is-estrogen.html