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Anti-Mullerian hormone (AMH) can provide more information about your reproductive health than almost any other hormone in your body. That’s because AMH is one of the best lab indicators we have for ovarian reserve — or the number of eggs in your ovaries.
While your AMH isn’t a predictor of your ability to conceive today or at a specific point in the future, testing your AMH through a blood test can help you understand potential outcomes for procedures like egg freezing and in-vitro fertilization (IVF), as well as point you toward signs that may suggest earlier menopause (when your menstrual cycles come to a complete stop).
How can low anti-Mullerian hormone levels (aka low ovarian reserve) potentially impact your reproductive health? We’re explaining it all, from what low AMH means for conditions like diminished ovarian reserve (DOR) to how it can influence time to pregnancy when you start trying to conceive.
What is AMH exactly?
AMH is produced by the preantral and antral follicles in the ovaries — these are the follicles (aka the tiny sacs that house and release eggs) that are in the active process of developing. The amount of AMH your body produces correlates with the number of developing ovarian follicles, which in turn correlates with the number of eggs remaining. The link between the number of developing follicles and the remaining number of eggs in the ovaries has to do with the relationship between primordial follicles (not yet developing and in a resting state) and the developing follicles. The developing follicles are only a proportion of the pool of primordial follicles. As the pool of primordial follicles goes down, the number recruited to start developing also goes down.
If your AMH is high compared to other people your age, you likely have a higher number of eggs and a longer reproductive window (the years between your first period and menopause). If your AMH is low compared to other people your age, you likely have a lower egg count and possibly a shorter reproductive window (and earlier menopause onset).
What’s considered low AMH?
“Normal” AMH levels for your age depend on your age group, as noted in the individual lab or test’s identified “reference ranges.” Reference ranges are the range of values for a physiological measurement (in this case, hormone levels) for the middle 95% of the healthy population. For AMH, we use cutoffs for different age groups according to the Beckman Coulter Access AMH assay. (An assay is a laboratory measurement technique.)
Modern Fertility has an additional label called “Slightly Low” for AMH values below 1.3 ng/mL. Even though 1.3 ng/mL is still within the normal range defined by the Beckman assay, we use this clinical decision limit because values below 1.3 ng/mL are more likely to be associated with lower success rates during fertility treatments like egg freezing or IVF.
“Low” levels are in the bottom 2.5% for an age group, while “Very Low” AMH levels are undetectable. (AMH hits zero at menopause because the follicles are no longer developing.)
For all AMH ranges across all age groups, check out this table (or read our in-depth guide on the hormone):
|AGE||NORMAL (IN NG/ML)||SLIGHTLY LOW AMH (IN NG/ML)||LOW AMH (IN NG/ML)||VERY LOW AMH (IN NG/ML)|
|18-25||Between 1.3 and 14.63||1.02 to below 1.3||Between 0.08 and 1.01||Below 0.08|
|26-30||Between 1.3 and 13.39||0.69 to below 1.3||Between 0.08 and 0.68||Below 0.08|
|31-35||Between 1.3 and 10.07||0.36 to below 1.3||Between 0.08 and 0.35||Below 0.08|
|36-40||Between 1.3 and 5.68||0.18 to below 1.3||Between 0.08 and 0.17||Below 0.08|
|41-45||Between 1.3 and 2.99||0.08 to below 1.3||Below 0.08|
What causes low AMH?
Low AMH typically has both biological and medical causes:
- For starters, AMH levels decrease with age for every person with ovaries, simply because ovarian reserve (or remaining egg supply) diminishes over time.
- People with endometriosis, a condition in which uterine tissue grows in other parts of the body, can also have lower AMH levels.
- Other studies have looked into genetic factors, including potential genetic variants that may result in low AMH.
- Auto-immune diseases that cause chronic inflammation — including rheumatoid arthritis, lupus, and thyroid diseases — can also impact your ovarian reserve and result in lower AMH levels.
- Certain chemotherapy regimens for cancer can lead to egg loss, and with fewer eggs, there’s less production of AMH.
Researchers are also studying how various lifestyle factors may result in lower AMH levels. A recent review highlights smoking and certain birth control medications as the only lifestyle factors demonstrated by multiple studies to decrease AMH. (And when it comes to birth control, hormonal contraception can suppress AMH, meaning that your levels may actually be higher when you’re off birth control.)
What are low AMH symptoms?
Low AMH doesn’t have any physical symptoms that we know of, so you can’t assume anything about your levels without testing them outright. But low AMH can cause specific issues in the body when it comes to fertility and reproductive health:
- Shortened reproductive window: If a person with ovaries has low levels of AMH (meaning lower than what’s “normal” for their specific age group), it can indicate that the duration of time when they’re able to conceive (aka their reproductive window) is shorter.
- Diminished ovarian reserve (DOR): There’s no AMH level that definitively indicates diminished ovarian reserve (DOR), but levels in people with DOR may range from <0.5 ng/mL to <1.2 ng/mL. A DOR diagnosis means you have fewer eggs than expected for your age. In these cases, there may be fewer reproductive years ahead (making having a family of your ideal size more difficult) and it can mean that egg freezing or IVF are less likely to be as successful for you when compared to someone with higher AMH.
- Primary ovarian insufficiency (POI): Primary ovarian insufficiency (POI) is characterized by undetectable AMH levels before the age of 40. Should your AMH test results reveal very low or undetectable levels of AMH and you’re younger than 40, talk to your healthcare provider about POI — which is known to have implications for cardiovascular and bone health. (Interestingly, irregular menstrual cycles don’t always happen with POI.)
It’s important to note that DOR and POI are not the same things, though they’re both associated with low or undetectable AMH. It’s kind of like how all squares are rectangles, but not all rectangles are squares. Everyone with POI has DOR, but not all people with DOR have POI.
Can you still get pregnant with low AMH?
While low AMH does impact your overall reproductive window, you can absolutely still get pregnant and have a successful pregnancy if your egg supply is in the lower range for your age group. After all, you only need one healthy egg and one healthy sperm to conceive. According to Dr. Temeka Zore, MD, FACOG — a fellowship-trained reproductive endocrinologist (REI), board-certified OB-GYN, fertility specialist, and Modern Fertility medical advisor — “what matters is the quality of the one egg being released, not whether it is coming from a pool of three follicles or 30 follicles.”
If you have low AMH and your cycle is regular, which is considered between 21 and 35 days long, you are likely going through ovulation. And if you’re ovulating, it’s possible to get pregnant. If your cycle is longer than 35 or shorter than 21 days, or you know you’re not ovulating, it’s important to talk to your healthcare provider to determine the cause.
But because low AMH levels may be correlated to a shorter reproductive window, it’s important to consider how that might impact your plans for kids — both in terms of when you start having them and how many you’d like to have.
If you have low AMH, will it take you longer to get pregnant?
This is still being studied, but the evidence we currently have indicates that there’s no difference in the length of time it takes to get pregnant. The biggest known challenge is the shortened reproductive window due to a lower amount of eggs — rather than the specific length of time it takes to conceive one pregnancy with one of those eggs.
Leading AMH expert and member of the Modern Fertility Advisory Board, Professor Scott Nelson, says that research into any associations between time to pregnancy and low AMH is ongoing. “While we await clarity on the link between AMH and the chance of natural conception, it’s clear that for women having assisted conception, a low AMH is associated with a lower chance of success at all ages,” he explains, “and their desired family size may be unattainable.”
Can fertility treatments help you get pregnant with low AMH?
Yes, fertility treatments can increase anyone’s chances of pregnancy — but low AMH levels don’t mean you need fertility treatment. If you have a regular cycle, it’s completely possible (and probable!) that you’ll get pregnant without intervention.
That said, if you have low AMH and want to hold off for a while before starting to have kids, you’re planning to have more children in the future, or you experience irregular cycles (which can make getting pregnant more difficult), you can talk to your healthcare provider about possible treatment options:
- Egg freezing can help you preserve eggs today so you’re able to use them in the future. And because frozen eggs don’t age, they’ll have the same egg quality as the day they were frozen. If egg freezing is something you can cover financially, doing it proactively (whether or not you have low AMH) can give you more options in the future as AMH declines over time. Keep in mind that low AMH may mean you will retrieve and freeze fewer eggs and your doctor may advise that you do multiple rounds of egg retrieval and freezing.
- In-vitro fertilization (IVF) is a fertility treatment where an egg is fertilized in a lab and the embryo is then transferred into the uterus. People with higher levels of AMH may have a higher number of eggs retrieved during the initial step of an IVF cycle (which, by the way, is the same initial step in the egg freezing process), and people with lower levels of AMH may need to undergo more cycles to retrieve the same number of eggs. The more eggs retrieved, the higher the probability you’ll have a viable embryo to transfer.
In certain cases, like when AMH levels are undetectable (where there are very few remaining eggs), your healthcare provider may recommend options like using donor eggs instead of your own eggs.
Can low AMH cause miscarriage?
This is another area of reproductive health where more research is needed to help us understand the relationship between AMH levels and miscarriage. A 2020 review and meta-analysis published in Fertility and Sterility identified a possible association between DOR and recurrent pregnancy loss.
One study in particular from 2018 published in Fertility and Sterility found that, after measuring the AMH levels of women trying to conceive, those who had experienced pregnancy loss before the 20-week mark all had the lowest AMH levels in the study. If a participant had significantly diminished ovarian reserve (which was defined as less than or equal to 0.4 ng/mL), they were 2.2 times more likely to have a miscarriage.
This information shows us that there may be a correlation between (low and high) AMH levels, but it does not prove that low or high AMH cause miscarriage. Lots of continued research will help us better understand how AMH may or may not relate to pregnancy loss.
Can you increase low AMH levels?
Remember that your AMH levels will inevitably decrease as you get older, so low AMH is normal and will happen to everyone with ovaries. But what if you find out you have low AMH at a younger age?
Right now, there’s no known “cure” for low AMH, but potential methods for increasing levels are being studied. One example: A study in the Journal of Human Reproductive Sciences found that moderate exercise was “associated with improved age-specific levels of ovarian reserve.”
It’s important to understand, however, that even if raising AMH levels was deemed possible, it wouldn’t reverse egg loss — once an egg is gone, it’s gone.
When does it make sense to test your AMH levels?
Whether or not you’re currently trying to conceive, testing your AMH levels can help you make proactive decisions about your fertility journey in the future:
- If you’re not actively trying to conceive but want insight into your reproductive window or potential outcomes for egg freezing and IVF.
- Understanding your AMH before you’re ready to have kids gives you a better idea of how to plan for the future so that you can have kids on the timeline you want.
- If you’re actively trying to conceive and want to better understand where your reproductive health is at today and map out your timeline for more kids in the future.
- If you’re actively trying to conceive but have not been successful yet, you can bring your AMH test results to your doctor to determine the best course of treatment options that are available to you.
Whether or not you’re trying to conceive right now, if you definitely want to have kids, then it’s always a good idea to talk to your healthcare provider about your goals and ideal timeline.
Retesting your AMH every 12 months can help you understand how your ovarian reserve is changing over time. When does Modern Fertility recommend testing more than once a year? If your AMH is changing rapidly, you have a lower AMH level, or you’re older, testing more frequently can help you stay on top of those changes and discuss your timeline with your partner and/or your doctor.
Even if your AMH test results are “normal,” Dr. Nataki Douglas, the Chair of the Modern Fertility Medical Advisory Board, still recommends tracking your levels over time (at least once a year) to stay on top of any changes. Remember, being proactive about reproductive health is key!
Plus, normal AMH levels don’t automatically translate to easy conceptions. Other fertility factors — such as egg quality or structural issues with the uterine cavity or fallopian tubes — cannot be detected by an AMH test. But by gathering as much info as you can, you can better navigate conversations with your doctor as you take that next step in your fertility journey.
This article was reviewed by Dr. Temeka Zore, a Modern Fertility medical advisor and reproductive endocrinologist at Spring Fertility in San Francisco.