Which Matters More for Fertility: AMH or Age?

People come into the doctor’s office often with concerns that they may never be able to have children, either because of their age or because of their lab results. The result they are usually referring to is their anti-Müllerian hormone (AMH) test. When an AMH comes back less than promising, people get anxious real quick.

But a single hormone level can never tell you that you can or cannot get pregnant. There is more to fertility than a person’s hormone level or their age, though the two are important. Let’s dig deeper into AMH and age and what they can really tell us about fertility. 

What is AMH?

An AMH test is a simple blood test commonly used to assess ovarian reserve. Ovarian reserve is defined by the National Cancer Institute as “the total number of healthy, immature eggs in the ovaries” but I find this to be a bit misleading. Let me explain why.

AMH is released by antral follicles, which are small, fluid-filled sacs in the ovaries that each contain a single oocyte (immature egg). Your AMH level is positively correlated with the number of antral follicles you have in your ovaries. Simply stated, the more follicles you have, the higher your AMH level typically is. 

The actual number on an AMH report is typically a single digit number that, again, corresponds to the number of healthy follicles you have but it isn’t the actual total number in your ovaries if we were to count them. For example, an AMH of 3.5 does not mean you have 3.5 follicles. It does mean that you likely have the expected number of healthy follicles in your ovaries and we expect that each of those follicles contains an egg that has the potential to lead to pregnancy. And since AMH is thought to be stable throughout the menstrual cycle, it’s considered to be the best lab indicator we have for a person’s reproductive potential (in combination with age). 

What AMH is actually very good at is predicting the timing of menopause. Research shows that AMH becomes very low or undetectable about five years before menopause. Other research has shown that the time of menopause may be predicted with a mathematical model using only one AMH value and the age of the patient. 

TL;DR? Your actual AMH number is not the total number of healthy follicles (with eggs in them) that you have, but it does correspond to your overall ovarian reserve, or your reproductive potential based on the number and quality of eggs you have. AMH is actually a better predictor of the timing of menopause, since it becomes very low or undetectable about five years beforehand.

AMH and age

So how does AMH relate to your age? ​​In younger people, a gradual increase in AMH levels is seen from the first day of life. Maximum levels are reached in the teenage years and they stay pretty steady until around the age of 25. After that, AMH and age are inversely correlated, meaning that as a person gets older, their AMH goes down. Additionally, the rate at which someone’s AMH goes down varies from person to person so it’s impossible to guess where someone’s AMH will be in the future.

What is a normal AMH for my age?

Unfortunately, there is no international standard for AMH levels. However, some studies have tried to assess AMH levels and create models for what is considered normal for specific ages. One study looked at the median AMH levels (in ng/mL) in 2,741 participants. Their results are listed below:

• Under 25 = 5.13
• 25 = 5.42
• 26 = 4.91
• 27 = 4.12
• 28 = 4.96
• 29 = 3.87
• 30 = 3.53
• 31 = 3.59
• 32 = 3.44
• 33 = 2.70
• 34 = 2.49
• 35 = 2.58
• 36 = 2.28
• 37 - 1.85
• 38 = 1.66
• 39 = 1.72
• 40 = 1.27
• 41 = 1.26
• 42 = 1.20
• 43 = 0.81
• >43 = 0.72

If you have a lower or higher AMH than the numbers above going into your 30s or 40s, I encourage you not to freak out! Remember that these are medians, which means many people have AMH levels above or below them. Multiple studies have shown that AMH doesn’t correlate with how likely you are to get pregnant. In fact, one study looked at AMH, FSH, and inhibin B levels and tracked people for a year. They found that there was no correlation between someone’s ovarian reserve and their ability to conceive and that a low ovarian reserve was not associated with lower fertility. As a result, they did not recommend the use of FSH or AMH levels to “assess natural fertility.”

Lastly, It’s also important to keep in mind that the interpretation of AMH levels is laboratory assay-dependent. This means it can be different from lab to lab and test to test. Your provider should give you the reference range for their specific lab. If you get your AMH tested in one lab and then get it tested at another lab later, let your provider know before comparing those numbers. 

Is AMH or age better at predicting egg quality?

Based on the research, AMH levels alone probably do not accurately reflect egg quality. Though, when AMH is combined with age, it can be a better indicator than when it’s used alone. There is unfortunately no single test or number that can tell you with certainty how likely you are to get pregnant.

Age, on the other hand, has been proven by countless research studies to be one of the biggest determinants of egg quality. As a person ages, their eggs are more likely to become aneuploid, meaning they’re “genetically abnormal.” This can lead to difficulties with both getting and staying pregnant (i.e, higher risk of miscarriages). Once a person reaches their mid to late thirties, research shows that the quality and quantity of eggs declines rapidly. 

Unfortunately, there’s not a lot we can do about aging or about the decline in AMH that goes with it. However, it does no good to stress about either of these numbers. As stated earlier, AMH and age are each just one value your provider looks at to assess your overall reproductive potential. Neither value alone can completely predict your chances of conceiving naturally and neither defines your fertility.

Is AMH or age better at predicting how many eggs will be retrieved during egg freezing?

A lower ovarian reserve can mean fewer eggs are retrieved during egg freezing. This means both age and AMH factor into the success of an egg freezing or IVF cycle. 

Research has found that AMH is a good predictor of the response to ovarian stimulation and the number of eggs retrieved, regardless of a person’s age. Because of this, fertility doctors typically use your AMH levels (along with other biomarkers) to determine the drugs and dosages you will need to maximize your response to ovarian stimulation. 

Now, what about a correlation between AMH and actual babies born (live birth rate)? Well, while AMH does seem to have some association with live birth rates after IVF, its ability to actually predict a live birth is not that great. This is especially true for younger people. A 2021 study found that AMH is a good predictor of live birth in older (>39 years old), but not younger, people. They found that younger participants (≤38 years old) could get pregnant even with low AMH levels as long as they had frequent egg retrievals. This is a great example of how age and AMH can both impact fertility.

At what AMH level should I freeze eggs? 

So when should you consider freezing your eggs? Honestly, the sooner the better. There is no specific AMH level at which you have to freeze your eggs. However, we know AMH only goes down as a person gets older, so the earlier you’re able to freeze your eggs, the better your response to the medications will be and, hopefully, the more eggs you’re able to have retrieved to keep your options open later.

When thinking about your AMH, these general guidelines for AMH values (ng/mL) and egg retrieval can be helpful:

• AMH <0.5 = predicts difficulty getting more than three follicles to grow in one egg retrieval cycle (this in turn reduces the chance for pregnancy with IVF)
• AMH <1.0 = suggests a limited egg supply and a short window of opportunity to conceive
• AMH 1.0 - 3.5 = suggests a good response to ovarian stimulation
• AMH >3.5 = suggests an ample egg supply (also indicates that your doctor may need to be cautious in order to avoid ovarian hyperstimulation syndrome (OHSS), a possible complication of ovarian stimulation)

So can you still freeze your eggs if your AMH is low? The simple answer is yes, you can. But you will be more likely to need more than one cycle to reach the ideal number of eggs.

You are not a number

With all the nuances involved here, it’s important not to get lost in the weeds. Fertility is impacted by so many factors that you can drive yourself crazy trying to manage all of them. Remember, you are more than any number. This process can be overwhelming, but focusing on the things that you can control can help you feel more grounded during your fertility journey, whatever it may look like. 

Freeze by Co is here to help you every step of the way on that journey. Our Split program allows people between 21 to 34 years old to have the chance to freeze their eggs for free! In a “Split” cycle, you would donate half of the eggs retrieved to a family that’s trying to conceive and freeze the remaining half for yourself. If you’re over 34, you can still participate in the Keep program up to age 40. In the Keep program, you’re able to freeze your eggs and keep them all for yourself, on your timeline. In addition, you’ll have access to our online support community, the Nest. This valuable resource lets you engage with other people freezing their eggs at the same time! 

Whatever your journey looks like, our team is here to guide you through it and keep your family-building options open.