Increased estrogen concentration

Increased estrogen concentration

A small deficiency in any of these hormones can be compensated by prolactin, a hormone of interest that was first found in mammals during breastfeeding of young animals.

Elevated concentrations of estrogen, progesterone and placental lactogenic hormone during pregnancy cause active growth of functionally mature breast tissue. Estrogen production is fetal dependent. Estrogens affect the production of progesterone, uteroplacental blood flow, the development of the mammary glands and the functioning of the adrenal glands of the fetus. By the 20th week of pregnancy, most of the estrogens secreted from the mother’s urine are derived from the androgens of the fetus. About 90% of maternal estriol is formed from precursors that have arisen in the body of the fetus.

The level of serum prolactin for childbirth rises from 10 (the level observed in non-pregnant) to 200 ng / ml. The content of prolactin in the amniotic fluid is more than 100 times higher than that in the blood of the mother or fetus at the beginning of pregnancy. It is not established whether this hormone is formed in the pituitary gland of the fetus or whether it secretes the trophoblast into the amniotic fluid. According to one hypothesis, prolactin can help an embryo survive in an aquatic environment, just as it helps teleost fishes (suborder Teleostei) to move from salt water to fresh water for spawning. An increase in estradiol occurs simultaneously with an increase in prolactin, indicating that the concentration of prolactin may increase under the action of estriol.

Although estrogens can initiate secretion of prolactin, in large quantities they block its physiological effects. Prolactin secretion is also controlled by the prolactin inhibitory factor. Reducing the level of estrogen after childbirth and suppressing the formation of a prolactin inhibitory factor, caused by stimulation of the nipples during feeding, increase the content of prolactin. If breastfeeding does not begin, within 1 week. serum level of prolactin is reduced to a characteristic characteristic of non-pregnant.

The last stage in a series of changes in the woman’s body, the purpose of which is to provide the newborn with breast milk, is the reduction of the duct system under the influence of oxytocin, which is formed in the posterior lobe of the pituitary, and the flow of milk to the nipples. After 3-4 months breastfeeding the act of sucking appears to be the only stimulant of lactation.

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