Estradiol is the most abundant of the estrogens, the group of steroids responsible for the development of sex organs and secondary sexual characteristics in women. Estradiol is involved in regulating the menstrual cycle and helps maintain pregnancy. Estradiol is also important for bone growth and metabolism in both men and women.
Levels of estradiol must be interpreted in light of the clinical situation (i.e. age, pregnancy, stage of the menstrual cycle, hyperthyroidism, cirrhosis, etc.) and associated hormone test results (FSH, LH, progesterone, etc.). In women and young girls, abnormally high levels of estradiol are found in early-onset puberty, ovarian and adrenal tumours, and following ovulation stimulation. In men, high levels of estradiol can be associated with gynecomastia (enlarged breasts), testicular and adrenal tumours, and delayed puberty. Low levels in women are normal during menopause but can also be associated with pituitary or ovarian dysfunction (polycystic ovaries), genetic problems (Turner’s syndrome), anorexia nervosa or extreme endurance exercise.