Poor ovarian reserve is a clinical condition in which the ovaries contain less number of oocytes (eggs) as expected for that particular age of a woman. Women are born with 1 to 2 million oocytes in their ovaries which rapidly declines, reaching 5 lakh oocytes at puberty. Out of these, only about 400 oocytes ovulate and are potential of giving a pregnancy. Rest of the oocytes regress and are lost.

The rate of loss is genetically predetermined. Most women will experience a significant decline in the quantity of their oocytes in their forties, while others may experience this much earlier. Those women who experience premature decline are considered to have diminished ovarian reserve or poor ovarian reserve. Although genetic factors are major cause of poor ovarian reserve, this diminish may happen because of other reasons also.

CAUSES AND RISK FACTORS OF POOR OVARIAN RESERVE

Age: Natural decline in ovarian reserve is observed as age advances. Decline starts after age 32 and accelerates after age 35.
Cigarette smoking and Alcohol : has been proved to accelerate ovarian aging and has a negative impact on fertility.
Genetic abnormalities : like Fragile X and other X chromosome abnormalities. Approximately 20 to 25% women with Fragile X syndrome experience primary ovarian failure and approximately 25% experience early diminished ovarian failure.
Radiotherapy and Chemotherapy : For various cancer treatment reduces ovarian reserve by causing damage to germ cells.
Ovarian surgery : such as for endometriosis, adenomas and other ovarian benign and malignant tumors. During excision of these tumors, some amount of normal ovarian tissue may be lost causing poor ovarian reserve.