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Age of the woman (43 years and above).
At birth, girls already have a certain number of eggs, programmed by nature; their number does not increase during life,but,on the contrary, decreases. At birth, the number of eggs is 400 thousand-1.5 million, which decrease monthly, die for unknown reasons. By the time of puberty(11-14 years), the ovaries contain about 300-400 thousand eggs.
Every month, several follicles are produced in the ovaries(15-25), but only one egg Matures, which is able to fertilize. The rest, inevitably die. This process can not be stopped, as well as to increase the number of eggs. Thus, the greatest number of oocytes (the scientific name of eggs), as well as their best quality falls on the age of 20-35 years. Then there is a decrease in quality and quantity. After 40 years, these indicators fall sharply. That is, the remaining oocytes are of poor quality and often with genetic abnormalities. This is why it is so difficult to get a pregnancy and a healthy baby after 40 years, even with the help of high technologies like IVF.
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Previously depleted ovaries or premature menopause.
The reason for this phenomenon may be:
– hereditary predisposition (mother and close relatives early menopause).
– surgical interventions on the ovaries(removal of cysts, etc.).
– endometriosis
-cancer and radiation and chimioterapia.
– removal of the ovaries.
-external factors(ecology, stressful situations, medication, radiation, bad habits, etc.).
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Resistant ovaries. That is, the ovaries are not sensitive to stimulation by hormonal drugs, they do not Mature follicles even at high doses of medications
* Congenital abnormalities of ovarian development.
* Genetic diseases of the mother that can be transmitted to the child.
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Repeated unsuccessful IVF with their own eggs(2 or more). In other words, low-quality embryos were obtained, there was no implantation and early miscarriages.
