While age alone is currently the most reliable indicator of egg number and quality, several tests can be utilized to help evaluate a woman’s ovarian reserve or ability to produce eggs.
- Antimullerian Hormone (AMH) level – Studies have demonstrated a gradual decrease in AMH levels as a woman gets older. This decline has been attributed to a decreasing number of eggs within the ovary. A low level of AMH suggests that the ovary may be depleted of eggs, and is predictive of low egg production (poor response) during In Vitro Fertilization (IVF). Low AMH levels are typically seen in older women, and in women with history of ovarian surgery, chemotherapy, radiation and/or endometriosis. Patients with endometriosis who undergo surgery to remove ovarian endometriosis cysts experience significant reduction in their AMH levels.
- Follicle Stimulating Hormone (FSH) level – FSH is an important hormone that regulates the recruitment and development of your eggs. The FSH level is less predictive of ovarian reserve status than the AMH level. In general, a low FSH level is reassuring, and indicates that you probably have good quality eggs. A high FSH level suggests that there is a reduction in both the number and quality of eggs remaining in your ovaries (Diminished Ovarian Reserve). The most reliable indicator of egg quality, however, is your age. So if you are 44 years old and you have a normal FSH level, you can not assume that the quality of your eggs is good. In fact, your chance of conceiving with IVF is less than 5%. Likewise, young women with high FSH may have fewer eggs remaining but their egg quality may still be good yielding satisfactory IVF pregnancy rates. Generally speaking, FSH levels below 10miu/ml are reassuring. Women with FSH levels over 20miu/ml rarely benefit from treatment utilizing their own eggs and they should be encouraged to consider donor egg IVF or adoption.
- Estradiol (E2) level – High estrogen level on day 3 of your menstrual cycle is indicative of Diminished Ovarian Reserve (DOR) even if the FSH level is completely normal. It is very important to measure both day 3 FSH and estrogen (E2) levels since an elevation in one or both tests may be equally predictive of decreased egg number and lower egg quality. Ideally, day 3 estrogen levels should be less than 50pg/ml. Day 3 estrogen level greater than 100pg/ml is considered abnormal.
- Antral Follicle Count (AFC) – This is an ultrasound examination to determine the number of antral follicles (immature eggs smaller than 10mm) present within the ovary.
A low number of antral follicles is suggestive of Diminished Ovarian Reserve (DOR) and may correlate with poorer IVF outcome. Patients with low egg numbers may consider IVF treatment as soon as possible. The egg count can also help the doctor determine which IVF stimulation protocol may be best for you.
Note in fig. 1 the numerous small dark follicles highlighted by white arrows indicative of good ovarian reserve. In contrast, few follicles are noted in fig 2 consistent with poor ovarian reserve.
Fig. 1 GOOD OVARIAN RESERVE
Fig. 2 POOR OVARIAN RESERVE
In summary, keep in mind that the ovary has a finite number of oocytes (eggs) available for ovulation during a woman’s reproductive years. Fertility in women begins to decline around the age of 27, and drops off more rapidly after the age of 35, reflecting the decline in the number and quality of eggs available for ovulation. A good ovarian reserve is most often correlated with younger reproductive age, high AMH, high Antral Follicle Count (AFC) and low FSH and estrogen levels.