Estradiol: the norm of the hormone in women
The content of the article:
- Functions and synthesis
- Norm
- The norm during pregnancy
- Increased and decreased hormone levels in women
- Blood test for hormone content
The rate of estradiol in women depends on many factors and varies during the day, the menstrual cycle and age. For men, only daily fluctuations in the hormone are characteristic.
Estradiol is a female sex hormone of a steroid nature, the most powerful of natural estrogens, which is responsible for the formation of the female reproductive system. In addition to estradiol, estrone (folliculin) and estriol, which are formed from estradiol in metabolic processes, belong to the family of estrogenic hormones. However, it is estradiol that is characterized by maximum physiological activity, affecting the organs and tissues of the female body related to the reproductive sphere: the vulva, vagina, uterus, fallopian tubes, mammary glands.
Functions and synthesis
Functions of estradiol in the female body:
- stimulates the growth of genital tissues;
- forms a number of female secondary sexual characteristics;
- regulates menstrual function;
- forms subcutaneous fatty tissue, distributing it according to the female type;
- regulates pregnancy and lactation;
- determines the psychophysiological characteristics of female sexual behavior.
The hormone also activates bone growth, oxygen metabolism in tissues, affects cholesterol levels, and causes fluid and sodium retention in the body.
Hormone rates vary depending on age, phase of the cycle, time of day, presence or absence of pregnancy
Estrogens are also found in the male body. In men, small amounts of estradiol are produced by the adrenal glands, testes, and peripheral tissue cells during the conversion of androgens.
In women, the hormone is mainly produced in the ovaries, in the membrane of the maturing follicle. A small amount of the hormone is also synthesized in the adrenal cortex and in the cells of adipose tissue. The precursor to estradiol is cholesterol, and testosterone and androstenedione are intermediate products of biosynthesis. Testosterone is partially converted to estradiol by the enzyme aromatase. The ratio of estradiol to testosterone is essential for the manifestation of its effects, in addition, this ratio regulates the synthesis of hormonally active substances of the pituitary gland according to the principle of feedback.
The control and activation of estradiol synthesis is carried out by tropic hormones (luteinizing and follicle-stimulating) and prolactin, and during pregnancy - by chorionic gonadotropin. Estradiol circulates in the systemic circulation with sex hormone-binding globulin, enters all organs and tissues, and is metabolized by the liver.
Norm
Indicators of the norm of estradiol depend on many factors, the concentration of total estradiol in the blood constantly fluctuates. Daily fluctuations in the concentration of the hormone in the blood are associated with the rhythm of its secretion. Tropic hormones that regulate hormone synthesis perform their regulatory functions at certain times of the day. The maximum amount of the hormone in the blood is noted from 15 to 18 hours.
For men, only daily fluctuations of the hormone are characteristic; in women, its content in the blood changes not only during the day, but also during the menstrual cycle. The level of estradiol in the blood of women in the early phase of follicle maturation is minimal, by the middle of the cycle it becomes three times higher and reaches its maximum value on the ninth day after the onset of ovulation. If conception has not occurred, from the tenth day after ovulation, the concentration of the hormone begins to decrease and reaches its lowest values by the end of the cycle. During the cycle, the ovaries produce about 10 mg of estrogen. If conception has occurred, the concentration of the hormone continues to increase.
Before puberty, the rate of estradiol in boys and girls is at the same level. In girls, the level of the hormone begins to increase in puberty, gradually reaching the indicators of sexually mature women, it is from this moment that menstruation begins.
During puberty, the hormone ensures the growth of the size of the uterus, vagina, external genitals. During this period, the development of female physiological characteristics occurs: the formation of the breast, adipose tissue and branching of the ducts for milk, the expansion of the pelvic girdle, the deposition of subcutaneous fat in the female type (in the thighs, buttocks, breasts), an increase in ciliated epithelial cells and an increase in their activity in the fallopian pipes.
The hormone rate in women depends not only on the phase of the menstrual cycle, but also on age.
The rate of estradiol in women by age:
- the norm of estradiol in girls of infancy (up to 60 days) is 5-50 pg / ml;
- the norm of estradiol in girls under 10 years old is up to 15 pg / ml;
- the norm of estradiol in adolescent girls is 25–30 pg / ml.
The hormone rate depending on the phase of the menstrual cycle in adult women:
- early follicular phase - 20–150 pg / ml;
- late follicular phase - 40-350 pg / ml;
- middle of the menstrual cycle (peak) –150–750 pg / ml;
- luteal phase - 30-450 pg / ml.
The amount of the hormone in the blood in women fluctuates depending on the phase of the menstrual cycle.
With the onset of menopause, the rate of estradiol gradually decreases and reaches the same values as in men. The hormone rate in postmenopausal women is up to 20 pg / ml.
The norm during pregnancy
During pregnancy, estradiol is produced by the placenta. It activates the metabolism in all tissues of the body, enhances blood circulation in the uterus, providing the fetus's needs for nutrients and oxygen, increases the growth and stretching of uterine tissues according to the needs of the fetus, is responsible for the state of the placenta, improves redox processes in the muscular layer of the uterus, preparing it the neuromuscular apparatus to active contractile activity, increases blood clotting, retains sodium and water. Under the influence of the hormone, the uterus becomes susceptible to the action of progesterone. The concentration of the hormone reaches its maximum value a few days before childbirth. A few weeks after the birth of the child, the indicators return to normal.
Table of normal estradiol indicators during pregnancy by week:
| Weeks of gestation | The amount of estradiol in the blood, pg / ml |
| 9-12 | 1030-2210 |
| 13-16 | 2000-4400 |
| 17–20 | 3300-7700 |
| 21-24 | 5100-11300 |
| 25-28 | 7100-14900 |
| 29–32 | 7900-19300 |
| 33–36 | 9400-22600 |
| 37–38 | 12300-23700 |
| 39-40 | 8300-26600 |
A hormone deficiency in a pregnant woman's body can cause a delay in fetal development, cause a miscarriage, and cause weakness in labor.
Increased and decreased hormone levels in women
An increase in the concentration of estradiol in the blood may indicate the following disorders:
- estrogen-secreting tumors of the ovaries and uterus;
- follicular ovarian cyst;
- endometriosis;
- hyperestrogenism;
- hyperplasia of the adrenal cortex;
- cirrhosis of the liver;
- hyperthyroidism;
- obesity.
Certain medications can also increase hormone levels.
Hormone levels below normal may indicate the presence of the following disorders:
- hypogonadism (insufficiency of the functions of the gonads);
- hyperprolactinemia (excess prolactin in the blood);
- dysfunction of the pituitary gland;
- inflammatory processes of the internal genital organs;
- sharp and significant weight loss, neurogenic anorexia;
- vegetarianism, unbalanced diet;
- excessive physical activity;
- smoking, alcoholism.
Also, a low level of the hormone may be the result of taking certain medications.
Symptoms of a low estradiol level include:
- violation of puberty;
- irregular menstrual cycle;
- premenstrual syndrome;
- dryness of the vagina;
- decreased libido;
- fast fatiguability;
- headaches;
- weight loss;
- osteoporosis;
- hirsutism (excess male hair growth in women);
- infertility.
Blood test for hormone content
A blood sample for the analysis of estradiol content is taken from a vein on an empty stomach, in the morning. A few days before the analysis, it is necessary to exclude physical activity, alcohol consumption, smoking, taking steroid drugs and pituitary hormones. Usually, in women, the analysis is performed on the 6-7th day of the cycle. To clarify the results, the study is performed several times, if necessary, in different phases of the menstrual cycle.
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
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