Dr Erin Fuller Fertility Specialist Square Logo

Let's Talk AMH
AKA The Ovarian Reserve

What is an AMH Blood Test?

When you’re born, you have a certain lifetime supply of eggs. The older you get, the more this supply slowly decreases in quality and quantity. The AMH blood test measures the how many eggs you could potentially produce at any one particular stage in your life.

Important: Whatever your AMH test score, there’s no guarantee you’ll fall pregnant. It’s only a gauge for your ovarian reserve (quantity), and it can’t tell us anything about your egg quality. Egg quality decreases with age, and there’s no current test for it.

Should I speak to my GP?

Yes. Any heterosexual or same sex couple should see their GP first to check if their health is optimal, and then be referred to a fertility specialist like me for a discussion and an AMH test. But bear in mind that not all GPs are comfortable in the fertility space, so if yours isn’t referring you on, don’t be afraid to see another GP who might be more inclined.

How accurate is the AMH blood test?

AMH test accuracy does come with some limitations, so please remember that the test isn’t 100% accurate — and it’s only one of many tools we use to gauge your fertility potential. Some of its limitations are:

  • Different interpretations: AMH levels can vary a lot from one individual to the next, and there’s no one universal standard for a “normal” or “optimal” score. In fact, your test score interpretation is complicated by factors like your age and ethnicity — and one woman’s low AMH level can be another’s normal range.
  • Ovarian reserve complexities: Factors like hormonal fluctuations during the menstrual cycle means we can’t always give you a consistent picture of your ovarian reserve levels.
  • We can only predict so far: The AMH test might tell us about your ovarian reserve, but it doesn’t give us an accurate prediction of your overall fertility. For example, even a woman with low AMH levels could still fall pregnant, while another with a high score might have issues.
  • Lifestyle and environment: Smoking, obesity, and stress can negatively affect your ovarian reserve and AMH levels. And so can being exposed to various chemicals.
  • It tells us nothing about egg quality: There’s quantity and then there’s quality. The AMH blood test is a measure of quantity: how many follicles remain in the ovaries; but when it comes to the quality of your eggs, it tells us nothing. And when it comes to successful conception and pregnancy, egg quality is critical..

What is the Anti Müllerian Hormone (AMH)?

The tiny cells in your developing egg sacs secrete something called the Anti-Müllerian Hormone (AMH), which has the potential to grow an egg. And when we take a sample of your blood, we can measure your AMH level, to get a good idea of your ovarian reserve: the number of eggs you have left.

Please note: Neither your menstrual cycle nor oral contraception will affect your AMH levels, so we can take your blood sample any time you like. 

Do I need an AMH test?

An AMH test could be your best option if: 

  • You’ve been attempting pregnancy for 6+ months
  • You’ll be conceiving in the future and want to know how your egg range compares
  • You’re contemplating IVF or other fertility treatments (note: a high AMH level might mean that your body is reacting to the actual IVF medication)

  • You’re worried that ovarian surgery or chemotherapy has impacted your chances
  • You think it’s possible you have an ovarian tumour

How does my age affect my chances?

I definitely take your age into account when looking at your AMH blood test score. If you have a low AMH test level, I may offer to move you onto treatments like IVF sooner than someone who has a normal or high level. But I also need to take into account the number of months or years you’ve been trying for pregnancy, any other factors in your test results, and what your preferences are as a woman at this stage in your life.

“The AMH level is a helpful tool, but it’s not the absolute reason why I’d decide whether to move you onto IVF.” 

When it comes to egg freezing for IVF later, it’s best to do it before you’re 38 —  because after that, your eggs are less likely to tolerate the freezing and thawing process, and therefore less likely to give you a pregnancy down the track. Age is definitely a factor, so the younger you freeze your eggs the better.

If you’re over 45, most of the discussion I’ll have with you will be whether you want to move onto donor eggs or not. Donor eggs are frequently used even with younger women, but being over 45 makes you more likely to need them. 

And don’t worry, it’s very common. In fact, there are so many celebrities having babies later in life, but nobody talks about the fact it’s not their eggs. (Except for Sonia Kruger, who is very open about it.)

What’s the AMH percentile by age?

This chart is what we use to help us determine where you sit in AMH levels. 

These are guidelines only. Statistical analysis on data from patients who conceived naturally.

Anti-Mullerian Hormone range versus age

“Any time you’d like to see a fertility specialist, even if it’s just to do some basic tests and reassurance, I’m very happy to see you — however soon into your journey.”