Anti-Müllerian hormone (AMH) testing is portrayed as the crystal ball of understanding your fertility. But is this based on robust research or just hype?
Women are born with all of their eggs for life—about 2 million. Over time eggs disappear unless they develop and are one of the lucky 450 to ovulated during a woman reproductive years. As women age, fertility declines along with the number of eggs left in her ovaries.Ovarian reserve is the term used to describe the number of eggs a woman has left. The AMH blood test is one of ways to quantify, for want of a better expression, how much petrol is left in the tank.
Normal AMH Levels
Depending on
AMH based predictions
So it seems sensible to reason that if doctors can measure the ovarian reserve it can provide women with valuable information about their current fertility and be used to predict how long they have left to conceive naturally, and even perhaps predict when menopause will happen.This is the basis of fertility testing, a quick blood test, to gaze into a personalised fertility crystal ball. But does research back up these claims? Let’s take a look into what AMH can, and perhaps more importantly, cannot predict.
AMH and IVF
AMH is great at predicting how well ovaries will respond to stimulation.Up to 30% of women respond poorly to controlled ovarian stimulation, resulting in fewer eggs and pregnancies than in women of a similar age. At the other end of the spectrum, women who over-respond, produce poor quality eggs, and are at risk of developing ovarian hyperstimulation syndrome (OHSS).So AMH can be used to counsel couples, and choose which stimulation regime to use for treatment. One would expect that if AMH can accurately predict response to stimulation, it would give a good idea of who will get pregnant or have a baby. However, AMH doesn’t predict the quality of the eggs and other factors such as age, cause and duration of infertility are also important. So AMH is not helpful in providing information on who will get pregnant.
The bottom line: AMH is great at predicting response to stimulation and number of eggs collected, but does not predict who will get pregnant or have a baby.
Natural fertility
So what do AMH test results mean for predicting the chance of getting pregnant now, and in the future?Sadly, for present fertility it means pretty much nothing. Researchers from Maryland, US, looked at 1202 women with low, normal and high AMH levels. Natural pregnancy rates were the same for all three groups
Long term fertility
Predicting future fertility using AMH results is what most commercial fertility testing is based on. However, very little research is available to support
The bottom line: AMH levels cannot predict the chances of conceiving naturally, and women with low AMH are as likely to get pregnant as those with normal or high levels. Future fertility is not guaranteed with a normal AMH level. Current evidence does not support using AMH as a useful screening test for present or future fertility.
Age of menopause
The average age of menopause is 51 years. Women over 40 have a significant fall in their fertility and the risk of miscarriage goes up. However, the individual age of menopause varies. About 1% of women will go through the menopause before they turn 40 and some will not reach menopause until 60. A study of 155 women found that AMH could predict time to menopause. However, this did stand true for women going through early or late menopause. The researchers concluded that AMH is insufficient to counsel patients about the end of natural fertility.
The bottom line:While data for using AMH to predict menopause is interesting. Currently, it is not helpful in identifying women at risk of early menopause.
Cancer patients
The American Society of Clinical Oncologists recommends that all women with a new cancer diagnosis should discuss the impact on their fertility and offer referral to a specialist. Chemotherapy is toxic to the ovary reducing ovarian reserve. Information on how chemotherapy will affect women with breast, and other cancers would be extremely helpful in counselling them about the likelihood that they will be affect by early menopause or if freezing eggs is something they may want to consider. Research has shown that AMH levels before chemotherapy or the drop in AMH do not predict the return of periods afterwards. While the return of periods and the ability to conceive are different, it is unlikely that AMH is useful in counselling women, or deciding on who is likely to benefit from fertility preservation.
The bottom line: AMH is not useful in predicting the effect of chemotherapy on fertility.
Ovarian injury from surgery
Surgery to the ovary for endometriosis or removal ovarian cysts causes damage to surrounding tissue containing eggs. AMH levels fall after surgery, but as previously discussed, levels do not accurately predict present or future fertility. Surgery, like all medical interventions, should only be performed when the benefits outweigh the risks. An experienced surgeon should operate, especially when fertility is a concern. Women considering surgery, must be appropriately counselled about the risk of reduced ovarian reserve so they can weigh things up before proceeding. Nevertheless, AMH is probably not helpful in providing an accurate reflection of how surgery may impact their fertility.
The bottom line: Surgery is complex and can be performed for many reasons, but may damage ovarian reserve. Weigh up the pros and cons before proceeding.
Polycystic Ovary Syndrome (PCOS)
A PCOS diagnosis is made when two or more out of the following three criteria are met:
- Irregular or no periods.
- Signs of increased male hormones (oily skin, spots, male pattern hair growth on face or abdomen, frontal thinning of the hair), or blood tests showing increased levels.
- Polycystic ovaries on ultrasound scan.
Notice that AMH does not feature in these criteria. Nevertheless, women with PCOS often have high levels of AMH. Whether this is due to having more follicles on ultrasound scan, or a reflection of an underlying disorder of overproduction remains unknown. High AMH levels in PCOS do not show better ovarian reserve, as the egg quality is poorer compared with normal ovaries. It has been suggested that AMH could be used as a less invasive alternative to trans-vaginal ultrasound scan. However, compared with ultrasound, AMH is far less reliable—only 60-70%.
The bottom line: AMH is raised in PCOS, but does mean these women have a better ovarian reserve.
Sources
Anti-Müllerian hormone—is it a crystal ball for predicting ovarian ageing?
Authors
Matt is an NHS Consultant in Newcastle with over ten years of experience. His PhD research into subfertility and miscarriage involved developing a clinical trial and patient engagement.