Estrogen tests are used to detect a deficiency or excess in a woman and to help diagnose a variety of conditions associated with this imbalance. They may also be used to help determine the timing of a woman's ovulation and may be ordered to monitor the health status of the developing baby and placenta during pregnancy. In a man, estrogen testing may be performed to detect a hormone excess and its cause. In Girls and Women Estradiol (E2) and/or estrone (E1) testing may be ordered to: Help diagnose early-onset puberty, when a young girl develops secondary sex characteristics sooner than expected; or delayed puberty, when a girl shows delayed development of secondary sex characteristics or start of menstruation. Investigate menstrual abnormalities, such as lack of menstrual periods (amenorrhea), infertility, and abnormal vaginal bleeding. Evaluate the function of the ovaries and detect ovarian failure. Monitor follicle development in the ovary in the days prior to in vitro fertilization by making serial measurements of estradiol. Monitor hormone replacement therapy that is given to assist fertility. Monitor menopausal hormone replacement therapy that is given to alleviate symptoms associated with estrogen deficiency. Detect estrogen-producing tumors. Monitor anti-estrogen therapy, as in breast cancer In Boys and Men Estradiol (E2) and/or estrone (E1) testing in boys or men may be ordered to: Help diagnose delayed puberty Help diagnose the cause of enlarged breasts (gynecomastia) or other signs of feminization Detect a relative estrogen excess that is due to a testosterone or androgen deficiency Detect estrogen-producing tumors Girls and Women: Early (precocious) puberty Tumors of the ovary or adrenal glands Boys and Men: Enlarged breasts (gynecomastia) Tumors of the testicles (testicular cancer) or adrenal glands Delayed puberty Both Women and Men: Hyperthyroidism Cirrhosis In women, decreased levels of estrogen are seen in: Turner syndrome, an inherited condition in women caused by a missing or abnormal X chromosome and characterized by underdeveloped female sex characteristics Low level of pituitary hormones (hypopituitarism) Dysfunction of the ovaries (female hypogonadism) Failing pregnancy (estriol) Eating disorders such as anorexia nervosa After menopause (estradiol) PCOS (Polycystic ovarian syndrome, Stein-Levanthal syndrome) Extreme endurance exercise Girls and Women: Early (precocious) puberty Tumors of the ovary or adrenal glands Boys and Men: Enlarged breasts (gynecomastia) Tumors of the testicles (testicular cancer) or adrenal glands Delayed puberty Both Women and Men: Hyperthyroidism Cirrhosis In women, decreased levels of estrogen are seen in: Turner syndrome, an inherited condition in women caused by a missing or abnormal X chromosome and characterized by underdeveloped female sex characteristics Low level of pituitary hormones (hypopituitarism) Dysfunction of the ovaries (female hypogonadism) Failing pregnancy (estriol) Eating disorders such as anorexia nervosa After menopause (estradiol) PCOS (Polycystic ovarian syndrome, Stein-Levanthal syndrome) Extreme endurance exercise