The ovaries of a newborn girl contain approximately 2 million eggs. By the time the girl reaches puberty, this number is reduced to 400,000 eggs. After puberty, the quantity of eggs progressively decline until the woman reaches menopause.
Many studies have shown that human fertility naturally declines with age. A woman’s ovarian reserve is used to describe the quantity and quality of the eggs available for fertilization. Poor ovarian reserve (POR) indicates a reduction in the quantity and quality of the eggs in women of reproductive age, and is an important cause of infertility for many couples.
How is it diagnosed?
For many years, there has been no universal definition for POR. In 2011, the European Society of Human Reproduction and Embryology (ESHRE) has worked on the definition of POR and introduced the Bologna Criteria to standardize the diagnosis of POR.
The Bologna criteria recommends the presence of at least two of the following three features for diagnosis of POR:
- Advanced maternal age (≥40 years) or any other risk factors for POR
- A previous POR (≤3 oocytes with a conventional stimulation protocol)
- An abnormal ovarian reserve test.
There are multiple ovarian reserve tests (ORTs) that provide an indirect assessment of the ovarian reserve. These tests will provide an estimate to the women’s sensitivity to ovarian stimulation and the relative chance for IVF success. The tests cannot predict a woman’s fertility in the future.
Typically, a day 3 FSH level and estradiol (E2) level are done to evaluate the ovarian reserve. Other tests include the clomiphene citrate challenge test (CCCP), antral follicle count (AFC), and anti-mullerian hormone (AMH) levels. Among the ovarian reserve tests, antral follicle count (AFC) and the anti-Mullerian hormone (AMH) level are the most sensitive and reliable markers of ovarian reserve. These markers permit the prediction of the whole spectrum of ovarian response with reliable accuracy.
What are the risk factors?
Age is the most important factor in predicting the ovarian reserve. The optimal age for women to conceive a child is before the age of 30. After that age, fertility starts to decline faster. The decline accelerates rapidly after the age of 37 years when the ovaries have less than 25,000 eggs.
In addition to age, other factors that affect ovarian reserve during reproductive age include endometrioma, certain pelvic infections, ovarian surgery, bacterial infections, chemotherapy, and radiotherapy. Obesity and chronic smoking is also believed to be associated with POR.
What are the success rates of IVF?
Women with POR are associated with low pregnancy success rates and high pregnancy loss. Currently, there are no available treatment interventions that can reverse the low quantity and quality of the eggs in women with POR. IVF is the only treatment option available with a reasonable chance of achieving pregnancy in women diagnosed with POR but the rates are much lower compared to women without POR. In a study of 1,152 fertile women undergoing IVF in China, the chance of conceiving a child were significantly lower in women with POR than those with normal ovarian response; 35.8% in women with POR vs. 62.8% in women with normal ovarian response.
Reference
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