γγThe measurement of sex hormone levels is an essential part of the endocrine examination and is one of the most important tools to understand the pituitary-gonadal axis, as well as an indicator to monitor follicular development in the evaluation of delayed sexual development, female infertility and in vitro fertilization. LH (luteinizing hormone), FSH (follicle stimulating hormone), PRL (prolactin), P (progesterone), E2 (estrogen), T (testosterone) and dehydroepiandrosterone are often found on the test results.γγ1. FSH, LH, E2 and T vary greatly in women at different times and need to be determined according to the menstrual cycle to determine if they are in the normal range. For women with a 28-day menstrual cycle, the follicular phase is usually the first half of the menstrual cycle, ovulation occurs around day 14 and the luteal phase is the second half of menstruation: FSH (mU/ml): Follicular phase 3.3-7.9 Ovulation 3.3-22.2 22.2 Luteal phase 0.7-5.0 Menopause 21-104 LH (mU/ml): follicular phase 2.0-12 Ovulation 23-109 Luteal phase 1.0-5.0 Menopause 10.9-58.6 E2 (pg/ml): follicular phase 18-195 Ovulation 130-459 Luteal phase 50-210 Menopause 3.2-37 P (ng/ml). Follicular phase 0.2-1.2 Ovulation 0.6-2.6 Luteal phase 5.8-22.1 Menopause 0.2-0.9 2. Androgens and prolactin remain stable in fertile women, with a normal range of 0.15-0.51 ng/ml for T and 3.5-24.2 ng/ml for PRL. Luteinizing hormone and follicle stimulating hormone mainly promote follicular development and ovulation. If the test value is too high, the ovarian function starts to decline; if it is too low, it may be a central endocrine disorder, such as anorexia and strenuous exercisers, but the ovarian function is not necessarily abnormal. If LH is significantly elevated high, it may be polycystic ovary syndrome, or PCOS. 3. Excessive prolactin may be due to pituitary tumors and hypothyroidism; or caused by medications, such as psychotropic drugs. Rarely, low prolactin, if levels are too low, can cause miscarriage. Ovarian tumors or pregnancy may manifest as high estrogen levels, and if low, they may be caused by central disorders, congenital gonadal abnormalities, ovarian dysplasia, and ovarian failure. Abnormal progesterone levels are less common. If the level is too low during pregnancy, it may cause miscarriage, and if the progesterone level is too low after ovulation, it may be luteal insufficiency. Elevated androgens may be the cause of acne, infertility, amenorrhea, and PCOS.