Diminished Ovarian Reserve
Diminished ovarian reserve at a glance:
- Diminished ovarian reserve is a condition in which a woman’s ovaries contain few eggs and/or eggs of poor quality, making conception more difficult.
- Women with diminished ovarian reserve were either born with fewer eggs than average, lost them more quickly than average, or over time the eggs accumulated more damage than average.
- Smoking, genetic abnormalities, cancer treatments with radiation and certain chemotherapy agents, and surgical removal of part or all of an ovary also can affect a woman’s ovarian reserve.
- With ovarian reserve testing, your physician can estimate whether your eggs have the fertility potential of most women your age, or if your ovaries demonstrate accelerated aging.
What is diminished ovarian reserve?
Ovarian reserve refers to the number and quality of eggs a woman has in her ovaries. Women with diminished ovarian reserve either have few eggs remaining, or eggs that are of poor quality. These women have a reduced chance of conceiving with in vitro fertilization (IVF) and other fertility treatments. They also have a higher chance of miscarriage.
In practical terms, ovarian reserve is the same thing as the biological clock. Most women are aware that there is such thing as a biological clock, but they are frequently uncertain when this clock really begins to tick. Some women remain fertile into their late 40s, while other women lose their fertility in their 20s and 30s.
While many cases of diminished ovarian reserve are never explained, common causes are:
- Age >35
- Genetic abnormalities (Fragile X premutation, or X chromosome abnormality)
- Cancer treatments with radiation and certain chemotherapy agents
- Surgical removal of part or all of an ovary
Why do some women lose their fertility sooner than others?
Every woman is born with all the eggs that she will ever have – approximately 2 million. Everyday, including through childhood, women lose eggs. Eggs are lost even if a woman is on birth control, is pregnant, or has infrequent menstrual cycles.
Additionally, as a woman ages, the eggs and the cells around them can accumulate damage that is never repaired. Therefore, as a woman ages, not only does she have fewer eggs, but a higher percentage of her eggs are abnormal due to damage from the aging process.
If she ovulates an abnormal egg, her chances of pregnancy are lower, and her chances of miscarriage and having a baby with an abnormality are higher.
Women with diminished ovarian reserve were either born with fewer eggs than average, lost them more quickly than average, or over time the eggs accumulated more damage than average.
The picture above illustrates the phenomena of egg depletion over time. The white circles represent normal eggs and the grey circles represent abnormal eggs. Notice that at birth, when egg number is at a maximum, there are a minimum number of abnormal eggs.
At the onset of puberty, a woman has already lost approximately 75% of the eggs she was born with. By the late 30s, egg number has continued to decline and notice that now the ratio of normal to abnormal eggs has shifted, with a much higher proportion of abnormal eggs. By the time of menopause, almost all remaining eggs are abnormal.
With ovarian reserve testing, your physician can estimate whether your eggs have the fertility potential of most women your age, or if your ovaries demonstrate accelerated aging.