Many women do not realise that a significant decline in fertility really begins in the early 30’s, not in the late 30’s or early 40’s as many people believe. In fact, for many successful fertility treatments, the biggest predictor of pregnancy outcome is the age of the female partner. The significant impact that age has on fertility is related to both the quality and quantity of a woman’s eggs.
In contrast to healthy men whose sperm cells continuously divide and renew themselves well into later life, healthy women are born with all the eggs that they will ever have. In fact, by the time a female infant is born, still many years away from reproductive potential, the number of eggs in her ovaries has already declined by 80% from their peak numbers. The numbers are even smaller by the time a girl enters puberty and begins to have menstrual cycles.
Ovarian reserve screening is one mechanism by which fertility specialists can partially predict the reproductive potential of a specific patient as well as the potential of her eggs to result in a healthy pregnancy. This information can be used to help couples decide which therapies may be emotionally and financially sound to pursue.
Ovarian reserve testing methods
- Anti mullerian hormone (AMH) is one potential test of ovarian reserve. None of the tests are perfect, and fertility specialists will often use a combination of tests to try to get a better estimate of the size of the remaining egg supply
What is AMH?
AMH is a protein used to measure a woman’s ovarian reserve. It reflects where she is in her reproductive lifespan or how close she is to menopause. AMH is produced by granulosa (follicular) cells in a woman’s ovary. Granulosa cells surround follicles which are small sacs containing immature eggs. These cells play a role in the development of follicles and the maturation of eggs, during a woman’s reproductive years. AMH also plays a key role in gender development during the first 8 weeks of an embryo’s development in utero.
At the beginning of each menstrual cycle, 5-7 primary follicles begin to develop from a pool of primordial follicles in a woman’s ovaries. This growth is caused by rising levels of FSH (Follicle Stimulating Hormone) in the blood. These follicles compete with each other for dominance, as only one will develop fully and release a mature egg from the ovary. AMH is produced by cells surrounding these growing follicles.
Advantages of Measuring AMH Levels
The advantage of measuring AMH is that throughout a menstral cycle, AMH levels remain consistent. This makes AMH a more reliable test, not constrained to measurement on specific days of the menstrual cycle like FSH and progesterone.
- The AMH test is useful in assessing conditions such as polycystic ovary syndrome and premature ovarian failure.
- A decrease in AMH signifying approaching menopause can be seen five years before a difference can be detected in the levels of FSH or Inhibin B.
- In clinical practice, AMH measurement may be useful in the prediction of poor response to fertility medication and cycle cancellation. It can also indicate a potential for hyper-response and ovarian hyperstimulation syndrome.