Breast development

begins at the age of 10-14 years, it is then that the functional activity of the gonads and adrenal cortex increases. During the reproductive period, all processes that are associated with the development of the mammary glands are hormonally determined.

The mammary gland is mainly affected by ovarian hormones – estrogen, progesterone; pituitary hormones, thyroid hormones, and adrenal glands also act. The functioning of the mammary glands is inextricably linked with the menstrual cycle.

Breast development diagram

  • Estrogens – promote the proliferation of cells that line the ducts and connective tissue frame of the mammary gland. An increase in estrogen levels contributes to an increase in the size of the mammary gland and pigmentation of the areola. Estrogens are direct stimulators of prolactin secretion, as they activate the gene that is responsible for the synthesis of prolactin.
  • Under the influence of progesterone, the alveoli of the gland are formed. 
  • Prolactin – promotes the development of cells that secrete milk – lactocytes. It is the main hormone that ensures breastfeeding. A significant increase in prolactin levels can cause tension, soreness of the mammary glands, and mastopathy may develop. Also, an increased level of prolactin outside of pregnancy – hyperprolactinemia – causes pathological discharge from the mammary gland – galactorrhea and cessation of normal ovulation. Prolactin helps stimulate the synthesis of proteins, fats and carbohydrates in milk. 
  • Thyroid hormones play an important role in the formation and development of mammary epithelial cells. 
  • Insulin affects breast cells indirectly, through other effects of hormones on organs and systems. 
  • Cortisol – helps in the formation of prolactin receptors, stimulates the growth of epithelial cells along with prolactin.

Risk factors for developing breast diseases

  • Hereditary factor (presence of benign and malignant tumors in maternal relatives);
  • hormonal disorders;
  • Neuroendocrine disorders (hormonal imbalance of the reproductive cycle leads to the growth of pathological processes in all hormonal-dependent tissues and organs);
  • Age exceeding 40 years;
  • First pregnancy at a late age;
  • Smoking;
  • Artificial termination of pregnancy interrupts the development of the mammary glands. In this regard, the tissue undergoes reverse development. The changes are uneven, the formation of mastopathy (diffuse and nodular) is possible;
  • Obesity. It has been proven that in combination with diabetes and arterial hypertension, the risk of breast cancer triples;
  • Long-term stress, which leads to changes in the secretory function of the endocrine glands;
  • Absence, very short or very long period of breastfeeding;
  • Number of births (women who gave birth to two children before the age of 25 have a risk of developing diseases three times less than women who have only one child);
  • Late menopause and early menarche.

Breast disease

The main role in the development of breast diseases belongs to progesterone deficiency conditions, in which there is an imbalance between estrogens and progesterone. Progesterone deficiency causes disruption of the structure of breast tissue and predisposes to the development of tumor changes. Most patients with gynecological diseases, especially those that developed against the background of a disturbed endocrine balance, suffer from one or another disease of the mammary glands.

At the same time, the highest risk group for severe pathology of the mammary glands are women with hyperplastic diseases of the female genital area (endometrial hyperplasia, polyps, endometriosis).

It is very important to remember that the gynecologist must pay increased attention to the condition of the mammary glands of his patients and treat them in close contact with specialist mammologists and endocrinologists.

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