Ovarian reserve refers to the reproductive potential left within a woman’s two ovaries based on number and quality of eggs.
Diminished ovarian reserve is the loss of normal reproductive potential in the ovaries due to a lower count or quality of the remaining eggs.
Normal aging causes most cases of diminished ovarian reserve (DOR) but genetic defects, aggressive medical treatments that harm the reproductive system (radiation for cancer), some surgeries and injury can cause DOR as well.
Ovarian reserve naturally declines with age.
Ovarian reserve is assessed through various tests important for fertility planning and treatment decisions.
In many cases there is no apparent cause for a relative decrease in ovarian reserve.
Women diagnosed with diminished ovarian reserve have the same reduced success of conceiving with in vitro fertilization (IVF) as they do with natural efforts to conceive.
In addition, women with DOR often have a greater risk of miscarriage when conceiving via IVF with their own eggs due to lower egg quality.
Ovarian reserve can also be considered a part of the biological clock, but this clock can vary from woman to woman.
Some women continue to be fertile in their 40s, while others begin to lose their fertility in their 20s.
In general, women start losing ovarian reserve before they become infertile and prior to the end of their menstruation, according to the American Society for Reproductive Medicine.
Women are born with around 2,000,000 eggs, which is all the eggs they’ll ever have.
Eggs are continuously lost, so by the onset of puberty most women have around 400,000 eggs left.
By a woman’s late 30s this number will have further declined to around 27,000.
At the onset of menopause most women only have around 1,000 eggs left in their ovaries.
Ovarian reserve can be estimated by measuring serum anti-Mullerian hormone levels and/or antral follicle count.
The number of all follicles 2 to 10 mm in diameter measured with ultrasound in both ovaries determines the follicle count.
Measurement of FSH levels and estradiol in the early follicular phase of the menstrual cycles days 2 to 4, when FSH is typically at its follicular phase peak provides indirect information about ovarian reserve.
More FSH is required to cause follicular maturity as ovarian reserves dwindle, the follicular phase shortens with earlier elevation of estradiol such that elevated levels of FSH and estradiol indicate decreased ovarian reserve.
Adequate ovarian, reserve thresholds are shown by an follicle count of at least 12, a level of anti-mullerian hormone greater than one nanogram per mL, and FSH level of less than 10 IU per liter, and an estradiol level of less than 80 pg per milliliter.
Decreased ovarian reserve is seen in approximately 26% of patients presenting to IVF centers.
Factors affecting ovarian reserve include: Age Genetics Previous ovarian surgery Chemotherapy or radiation exposure Smoking Medical conditions
Ultrasonography is used to measure the antral follicle count (AFC), which includes counting all follicles 2 mm to 10 mm in diameter in both ovaries.
A normal AFC is at least 12 follicles.