1. Anti-Mullerian Hormone (AMH) Anti-Müllerian hormone (AMH) is produced by cells (granulosa cells) that surround each egg in the ovary. Consequently, the more eggs recruited at the beginning of each menstrual cycle, the higher the AMH blood level. In short, AMH serves as a long-term forecast of your ovarian reserve, and age-related declines in AMH levels reflect the decreasing number of eggs in the ovary. As mentioned above, we prefer our egg donors aged 18-34 to have an AMH level of 2 or greater (Good ovarian reserve), while an AMH value less than 1 raises concern for diminished ovarian reserve (DOR). Levels greater than 4 indicate a high ovarian reserve, meaning more eggs are available for fertilization. Although generally a positive sign for fertility, extremely high AMH can also be associated with conditions like PCOS and indicates a higher risk of ovarian hyperstimulation syndrome (OHSS) during IVF. If you are interested in fertility preservation through planned egg banking (freezing), an AMH between 1 and 4 suggests that we will likely retrieve many eggs after ovarian stimulation. When the AMH levels are below 1, this may indicate that a reduced number of eggs is likely to be recruited for planned egg banking. In this situation, a woman may need to consider undergoing more than one cycle of egg harvesting to accumulate and store her desired number of eggs. When is the best time to test AMH? Unlike other tests for assessing a woman's ovarian reserve, AMH does not need to be tested at a specific time in her menstrual cycle and can be tested at any point, regardless of whether she has regular menstrual cycles. Therefore, AMH is the best test to estimate how your ovaries will respond to fertility medications and the optimal dose of fertility medication for your fertility treatment plan. 2. Follicle Stimulating Hormone (FSH) Unlike AMH, which is produced in the ovaries, FSH is a hormone produced by an organ in the brain called the pituitary gland. It does what its name implies—stimulates a follicle that usually houses the egg within the ovary to grow in preparation for the release of the egg at ovulation. Women produce the highest FSH levels before the ovulatory phase of their menstrual cycles in the first five days. This is the optimal time to obtain a blood test and determine the maximum FSH level. The follicles and the surrounding cells that contain the eggs should respond quickly to FSH, releasing estrogen into the bloodstream. Estrogen signals the brain to avoid releasing too much FSH. Thus, the follicle that has recruited the largest number of FSH receptors continues to respond to the falling levels of FSH and is therefore recruited to be the one that would be ovulated in any particular cycle. This helps to prevent the release of more than one egg per month. Low FSH and estrogen levels suggest that the pituitary gland needs minimal work to kick start the ovary to “work” each month. Conversely, if the eggs in the ovary are too few and not very responsive to FSH (indicating diminished ovarian reserve), the brain compensates by releasing abnormally high amounts of FSH, prompting the ovary to work harder to release an egg. FSH is best measured at the beginning of the menstrual cycle, specifically from day 2 to day 5 of menstrual flow, with day 1 being the day of full flow, not spotting. An FSH level of 8 or less represents good ovarian reserve. When it is greater than 10, it raises concern for diminished ovarian reserve. An FSH value of 15 or greater raises a significant concern for a substantial decline in the fertility potential of your eggs. An FSH value of 20 or greater suggests a very low fertility potential. However, a very high FSH does not mean a woman cannot get pregnant because all she needs is to ovulate or have a chromosomally normal egg aspirated and fertilized in an IVF cycle. There are several examples of live birth following IVF in women with a baseline FSH greater than 20. It should be noted that FSH levels can vary from month to month. It is often unnecessary to repeat this test, but when done, the higher of the two values represents the true ovarian reserve. Also, different women can respond differently despite the same baseline FSH level. This is often a function of their ovarian age. Two 38-year-old women with an FSH of 12 will respond differently to ovarian stimulation depending on their ovarian age. One that is destined to become menopausal at age 45 will likely produce fewer eggs compared to one that is destined to get to menopause at age 55. Unfortunately, no test can tell when a particular woman will become menopausal before this event. The age when their mother became menopausal is an indicator, but not a good one. 3. Estradiol (E2) Estradiol is the primary form of estrogen in women during their reproductive years. FSH from the brain drives the release of estradiol from the cells (granulosa cells) that surround eggs in the ovary. An abnormally high level of estradiol, 100 or greater, in the first five days of a woman’s cycle indicates that FSH activity is also excessively high. This is true regardless of whether the FSH blood test value is normal (less than 10 at that time) and signifies diminished ovarian reserve. 4. Antral Follicle Count (AFC) One of the best ways to assess ovarian reserve is to count the number of resting follicles (less than 10 mm in size) in both ovaries during the first five days of a woman's menstrual period. The younger a woman is, the more follicles are recruited in the early follicular phase. Ideally, around 10 to 20 total follicles are regarded as normal. An antral follicle count (AFC) lower than 8, may indicate diminished ovarian reserve. The number of resting antral follicles also estimates how many eggs may be recruited for fertility treatments with ovulation induction, whether for intrauterine insemination (IUI) or IVF. We expect our egg donors, aged 18-28 years, to have at least 16 resting antral follicles. Women with an excessive AFC of more than 25 resting antral follicles on each ovary and irregular menstrual cycles may experience infertility related to polycystic ovary syndrome.