Loss of eggs or oocytes is the basis for lower fertility and higher miscarriage rates seen in women as they age. Decline in ovarian reserve begins in the early thirties, accelerates in the late thirties and plays a significant role in the increased incidence of infertility in the forties. This natural decline in ovarian oocytes varies among women. Some women will experience a decline in egg health in their 20’s while others remain fertile into their early 40’s. Tests to assess ovarian reserve are useful for both the physician and couple experiencing infertility as they provide a more complete understanding of the likelihood of a woman conceiving with her own eggs. However, there are limitations to all tests such that some women with poor or abnormal results may still conceive a healthy child with their own eggs while others with normal results could still have unhealthy embryos with continued infertility. Several tests are now available to assess egg reserve.
- The most common test of ovarian reserve is the cycle day “3” FSH and Estradiol. These blood tests can actually be drawn on day 2, 3, or 4 of the menstral cycle. FSH is a hormone produced by the pituitary gland in the brain, not by the ovary or the egg and as such, is an indirect measure of ovarian functioning. Although most widely obtained and studied regarding predictability of egg reserve, the test result can vary from menstral cycle to menstral cycle making the results less reliable. The current concept is that an abnormal result is indicative of decreased chances that a woman will conceive with IVF and takes president over prior or subsequent normal results. A normal fertile FSH level is generally <10 mIu/mL with the estradiol level <75pg/mL.
- Anti Mullerian Hormone – AMH is also a blood test reflective of ovarian reserve. Unlike FSH, blood work can be obtained at any time during the cycle and the level shows less cycle to cycle variability. AMH is generated within the ovary and therefore is considered to be a more direct measure of egg health; however, since it has been utilized to measure ovarian reserve more recently, it has not yet been adopted as ‘the gold’ standard for ovarian reserve testing. A normal value for most labs is greater than 0.7.
- Antral Follicle Count and Ovarian Volume – These tests are obtained using transvaginal ultrasound measurements usually early in the menstral cycle. The size of the ovaries and number of visible immature follicles present early in the cycle has been demonstrated to reflect the number of eggs that have the potential to develop during a treatment cycle.