Ovarian Reserve and Egg Quality: FSH, AMH, and AFC
When a woman is facing fertility challenges, one of the first fertility markers to be evaluated is her ovarian reserve. Ovarian reserve refers to a woman’s current supply of eggs within her ovaries, and it is closely associated with reproductive potential. In general, the greater the number of eggs remaining, the better the chance of conception. This is because a higher ovarian reserve means a larger pool of eggs to recruit from each month for maturation and ovulation. As a woman ages, her supply diminishes, reducing her fertility until all of the eggs are depleted at menopause.
If a woman decides to seek treatment from a fertility clinic to pursue IUI or IVF, the reproductive endocrinologist will use specific tests to determine egg quantity. These specific tests to estimate ovarian reserve will help a doctor decide whether IVF is a feasible option, what type of protocol to follow, and the chance of success of that protocol. The more eggs there are to recruit, the more successful the stimulation hormones will be, generally speaking.
What should be emphasized, however, is that quantity of eggs does not automatically translate to quality of eggs. There can be a high ovarian reserve with poor egg quality. Conversely, a young woman may have a low ovarian supply due to genetic factors, but she may still have good quality eggs.
Usually a woman’s age is combined with her estimated ovarian reserve to predict the quality of her eggs. Because there is not a medical test to determine egg quality, the only real test of egg quality is a live birth.
Determining Ovarian Reserve with FSH
Follicular stimulating hormone (FSH) levels are measured on Day 3 of the menstrual cycle. Levels of FSH are dependent upon a negative feedback system between the ovaries and the hypothalamus and pituitary glands. FSH from the pituitary gland signals to the ovaries to recruit immature ovarian follicles, or antral follicles. These antral follicles begin to develop, and one of these recruited follicles will eventually grow large enough to become the ovulated ovum, or egg. As the follicles grow, they send their own hormonal signal back to the hypothalamus which shuts down the FSH secretion from the pituitary. Healthy, responsive ovaries need very low levels of the hormonal signal from the pituitary. In other words, well responding ovaries are reflected in low levels of FSH. High levels of FSH indicate the ovaries are not responding, which reflects a diminished ovarian reserve. FSH levels will fluctuate from month to month and are dependent upon estrogen levels. High serum estrogen will suppress, or lower, FSH levels.
FSH levels
In general:
under 6 is excellent
6-9 is good
9-10 fair
10-13 diminished reserve
13+ very hard to stimulate
Determining Ovarian Reserve with AMH
In recent years Anti-Müllerian hormone levels have also have also been used to predict a woman’s fertility because it has been shown to be a better predictor of ovarian reserve. Anti-Müllerian hormone (AMH) is a substance produced directly by the ovarian follicles and is only present in a woman until menopause. The level of AMH directly correlates with the number of antral follicles in the ovaries and can be measured at any time in the month. It has been documented that women with lower AMH have lower antral follicle counts and produce a lower number of oocytes compared with women with higher levels. Therefore, the higher the level, the greater the ovarian reserve. Some woman, especially those with polycystic ovarian syndrome (PCOS) may have very high AMH levels.
AMH levels
In general:
1.0-3.0 ng/ml= normal
Under 1.0 ng/ml= diminished ovarian reserve
Over 3.0 ng/ml= possible PCOS
Due to the fact that AMH levels decline as a woman ages, this value has been shown to be a reliable gauge of ovarian reserve, however, according to a review article published in Reproductive Medicine and Biology (Vol 15, No 3), it has not yet been determined to be a reliable predictive marker for live births.
One important note regarding AMH levels was illustrated by a recent study published in JAMA in October 2017. This study showed that AMH levels are only valuable in predicting fertility in woman who have been TTC for more than 3 months. For the average woman, AMH levels mean almost nothing in relation to overall fertility and fecundity. AMH also loses its predictability in woman under the age of 35 years.
Determining Ovarian Reserve with AFC
Perhaps the best indicator of ovarian reserve is to measure antral follicle count or AFC. Antral follicles are imaged during the early follicular phase using a transvaginal ultrasound. Eight to ten total follicles between the two ovaries predicts a healthy response to an IVF cycle. Less than that amount potentially indicates diminished ovarian reserve. A count above 14 is a good indicator of hyper-response during a stimulation or a predictor of ovarian hyperstimulation syndrome (OHSS).
What It All Means
Western medicine loves numbers and stats. It is the way success is evaluated, predictions are made, risks and benefits are gauged. Lab values and measurements drive conventional medicine, and in many ways, this hard data is essential in dictating treatment options and outcomes. However, numbers are only numbers. They only give one perspective of the story.
Remember that you are more than your lab values, and that these tests do not DICTATE your reproductive potential.
Things to Remember
-AMH, FSH, and AFC values are used to evaluate the ovarian reserve.
-AMH, FSH and AFC values help determine which stimulation protocols to use for IVF cycles in women undergoing IVF treatment. They are particularly important in evaluating women over the age of 35.
-AMH, FSH, and AFC values CANNOT determine a woman’s ability to conceive. These are only lab values and numbers. They do not tell the whole story.