You’ve just received some of the most upsetting news a woman can receive. Your AMH is low. Now what?
AMH is Antimullerian hormone. AMH is a blood test that can tell us about your egg count. A low AMH tells us that your overall egg count or ‘ovarian reserve’ is low, or diminished. An AMH level <1.0 ng/dl is considered low. Most women of reproductive age have an AMH level between 2.0 – 4.0 ng/dl. If your level is 5.0 ng/dl or above, it may be an indicator that you have either an above average egg count, or a condition called Polycystic Ovarian Syndrome (PCOS).
Women with AMH levels under 0.5 ng/dl have severe diminished reserve. Women who are close to or in the menopausal transition will have an undetectable AMH level, or 0 ng/dl.
What are signs that you may have a low AMH? There are typically no obvious symptoms that your egg count is low. Some women may report that the length of their menstrual cycles have become shorter. So if you are currently having a period every 24 days, but 5 years ago they were coming every 28 days, this pattern is suspicious for diminished ovarian reserve. Menopause typically occurs around age 50, but for some women, it comes much earlier. Women in their 20s, 30s, and 40s can go through menopause, and this is called “Premature Ovarian Insufficiency”. If you are experiencing a pattern of periods coming closer and closer together (eg. Every 21 days), followed by a window of missing your period every few months, you may be in the menopausal transition. The final step of menopause is when periods completely stop, and is defined when a woman has not had a period for 12 months. This indicates that the egg count is close to but not quite zero.
Why is my AMH low? Why is this happening? In over 90% of cases, we never discover the cause of why AMH is low. Ovarian reserve, much like a woman’s height, seems to be a spectrum and is likely genetically predetermined. We suspect that some women are born with less eggs than others, or that some women’s monthly egg loss occurs more rapidly than others. A few risk factors for diminished ovarian reserve have been identified and include: cigarette smoking, history of chemotherapy or radiation for cancer, ovarian surgery, endometriosis, and genetic conditions such as fragile X permutation carriers.
It is important to note that no medications have been shown to cause low AMH. Specifically, oral contraceptive or birth control pills, as well as IUDs or Intrauterine devices, DO NOT cause infertility or diminished ovarian reserve. While birth control pills may cause a temporary decrease in the AMH results, as much as a 30-50% decrease in true AMH, we should note the true AMH level if we recheck AMH 2-3 months after coming off of birth control pills.
Should we recheck my AMH? Often women want to know if the AMH result is accurate. It is reasonable to recheck the AMH, but almost 100% of the time, the recheck confirms the findings. We can also confirm the diagnosis of diminished ovarian reserve with another blood test called FSH (Follicle Stimulating Hormone) which is a blood test that must be checked between days 2-5 of the cycle. FSH levels of 10 or above indicate diminished ovarian reserve.
Is there anything I can do to change my AMH level and make it higher? No, unfortunately there is no medication, treatment, or lifestyle changes that will improve your AMH.
What is my prognosis? Will I be able to have a baby? Often the prognosis depends on a woman’s age. A 30 year old with a low AMH has a better prognosis than a 40 year old with low AMH. This is due to egg quality, or the proportion of eggs that remain in a woman’s ovaries that still have normal chromosome number. For example, a woman under 35 years of age can expect about 70% of her eggs to be good quality or viable. These eggs can be fertilized by a sperm and result in a chromosomally normal embryo which can result in a live birth. The other 30% of her eggs are abnormal. Now, the ovaries don’t know which eggs are the normal eggs and which are the abnormal eggs. Each month, one egg is released or ovulated, and statistically 70% of the time ovulation will result in a normal egg being released.
There is no test for egg quality. We know that age is the only marker for egg quality. We know this based on embryo data from patients who have undergone IVF with genetic testing of embryos (PGTa). Egg quality drops dramatically each year starting around age 36. At age 40, a woman can expect 30% of her eggs to be normal and the other 70% to be abnormal. At age 45, a woman can expect only 5% of her eggs to be genetically normal.
So even if a young woman has diminished ovarian reserve, we know that each month there is a 70% chance that the egg that is ovulated will be normal. Young women with DOR can still have success with treatments such as IUI and IVF. However, for women in their late 30s and 40s, chance of successful conception gets much lower. This is because fertility treatments depend on stimulation of the ovaries, and the more eggs we can get to grow, the better the chance of success.
In the case of IVF, it typically takes about 3-6 eggs to yield one good embryo. This is because not every egg is mature, and not every mature egg fertilizes, and not every fertilized egg (embryo) survives the 5 days of growth in the lab to become a blastocyst. So if you are 30, and we get 5 eggs at an egg retrieval, we will likely end up with 1-2 embryos, each with a 70% chance of leading to a live birth. The only difference between the 30 year old with DOR and a 30 year old with normal ovarian reserve is that the woman with normal ovarian reserve will likely have more embryos to freeze and use in the future to continue to build her family.
Now if you are 40 years old and we get 5 eggs, we will still get 1-2 embryos, but this time each one only has a 30% chance of resulting in a pregnancy. And because there are no embryos to freeze, this woman would have to another (and possibly multiple) rounds of IVF which can be quite costly. Often women who are not successful after 2-3 tries of IVF will move to egg donor IVF. Even if you have not had success with IVF, your chance of success with an egg donor is 65% because pregnancy chances are based on the age of the egg and not the age of the woman carrying the pregnancy. Egg donors are typically in their early 20s.