A low AMH result can land with more emotional weight than almost any other fertility number. Searching for the top causes of low AMH is a sensible next step, but the result needs careful interpretation. AMH is one useful piece of your fertility picture, not a prediction of whether you can conceive naturally, the quality of every egg you have, or your worth as a future parent.
AMH, or anti-Müllerian hormone, is produced by small follicles in the ovaries. It is commonly used as an indicator of ovarian reserve - the remaining pool of eggs that may be available for future ovulation. A lower result can suggest a smaller number of recruitable follicles, particularly when considered alongside age, an antral follicle count scan, cycle history and other hormone results.
The cause is not always obvious, and it is not always something you could have prevented. Clear, timely testing and clinician-led interpretation can replace frightening assumptions with a plan that fits your circumstances.
What a low AMH result does and does not mean
AMH tends to decline as ovarian reserve reduces with age. In fertility treatment, it can help clinicians estimate how the ovaries might respond to stimulation medicines. It may also inform conversations about timing, IVF, egg freezing or further investigation.
It does not directly measure egg quality. Egg quality is more closely associated with age, although individual outcomes vary. Nor does low AMH mean pregnancy is impossible. People with low AMH can conceive without treatment, while people with a higher result may still face other barriers such as ovulation problems, blocked tubes, endometriosis, sperm factors or implantation concerns.
Reference ranges also vary between laboratories and test methods. A result should therefore be assessed using the laboratory’s own range and your full medical picture, rather than against a figure seen online.
The top causes of low AMH
Age-related decline in ovarian reserve
Age is the most common reason AMH falls. Everyone with ovaries is born with a finite number of eggs, and that number decreases over time. The decline is gradual for many years, but it often becomes more pronounced from the mid-30s onwards. This is a normal biological process, not a sign that you have done anything wrong.
The exact pace differs widely. Two people of the same age can have very different AMH levels and very different fertility experiences. That is why age is powerful context, but never the whole story.
A naturally lower starting reserve
Some people have a lower ovarian reserve than expected for their age without an identifiable illness or event. Genetics may contribute, including a family pattern of early menopause or premature ovarian insufficiency. If a mother, sister or close relative experienced menopause unusually early, it is worth mentioning during a fertility consultation.
Certain genetic conditions can also be associated with reduced ovarian reserve. Where a result is unexpectedly low, especially in someone under 35 or with irregular or absent periods, a clinician may suggest targeted blood tests, genetic assessment or referral to a reproductive medicine specialist.
Premature ovarian insufficiency
Premature ovarian insufficiency, sometimes called POI, occurs when ovarian function declines before age 40. It is different from menopause because ovarian activity can be intermittent, and occasional ovulation or periods may still happen. However, it can be associated with low AMH, irregular cycles, hot flushes, night sweats or vaginal dryness.
POI has several possible causes, including genetic factors, autoimmune conditions and previous medical treatment. In many cases, no single cause is found. Receiving this possibility can feel overwhelming, but early specialist support matters both for fertility choices and for longer-term health, including bone and heart health.
Ovarian surgery and endometriosis
Surgery involving the ovaries can reduce ovarian reserve, particularly if ovarian tissue must be removed. This may happen when treating ovarian cysts, torsion or endometriomas - cysts linked with endometriosis. The effect depends on the condition, the size and location of cysts, the surgical technique used, and whether one or both ovaries are affected.
Endometriosis itself may also be associated with lower AMH in some people, especially when endometriomas are present. Yet surgery is not automatically the right answer for someone trying to conceive. Removing a cyst may relieve pain or be necessary for another clinical reason, but it can also affect reserve. This is a decision best made with a gynaecologist or fertility specialist who can weigh pain, ovarian reserve, treatment plans and the potential benefits of preserving eggs or embryos first.
Chemotherapy, radiotherapy and other medical treatment
Some cancer treatments can damage eggs and follicles. The impact of chemotherapy varies considerably according to the medicines used, dose and age at treatment. Radiotherapy directed at or near the pelvis can also affect ovarian function, while total body radiation may carry a higher risk.
If treatment has not started, urgent fertility preservation advice may be possible. Depending on time and medical suitability, options can include egg, embryo or ovarian tissue freezing. If treatment happened in the past, an AMH test and specialist assessment can still provide useful information, although a low result alone cannot determine whether natural conception is possible.
Smoking and potentially modifiable influences
Smoking is associated with earlier menopause and may contribute to faster loss of ovarian reserve. Stopping smoking is one of the most meaningful steps for fertility and pregnancy health, regardless of AMH level. It can also support sperm health in a partner.
Evidence around alcohol, stress, supplements, diet and environmental exposures is more complicated. A balanced diet, movement, sleep and reducing alcohol can support overall reproductive health, but no supplement, cleanse or lifestyle protocol has been proven to restore the egg supply or reliably raise ovarian reserve. Be wary of promises that a low AMH result can be reversed. The more useful goal is to understand the result, protect the fertility potential that remains where possible, and make decisions with good information.
Test timing, contraception and result variation
AMH can usually be measured at any point in the menstrual cycle, which makes it a convenient test. Still, results can vary between assays and laboratories. Hormonal contraception may lower AMH readings in some people, and levels can change after pregnancy or while breastfeeding. A recent ovarian procedure or certain medical treatments can also influence interpretation.
For this reason, one unexpected result sometimes warrants repeat testing, ideally using a comparable laboratory method, alongside an ultrasound antral follicle count. Repeating a test is not about delaying action. It is about making sure significant decisions are based on the clearest possible evidence.
When low AMH needs a wider fertility assessment
AMH only assesses one side of the fertility equation. If you are trying to conceive, a complete assessment should consider whether you are ovulating, the regularity of your cycles, uterine and tubal factors, medical history, and sperm health where relevant. Testing both partners early can prevent months of uncertainty and avoid placing the full burden of investigation on one person.
Seek advice sooner if you are under 35 and have been trying for a year, are 35 or over and have been trying for six months, or have irregular periods, known endometriosis, previous ovarian surgery, past chemotherapy or radiotherapy, recurrent miscarriage, or concerns about sperm health. If periods stop suddenly or symptoms suggest early menopause, arrange medical review promptly.
Turning a result into a practical next step
A low AMH result may change the pace of your plans, but it does not tell you there is only one path forward. For some people, the next step is reassurance and a realistic conception timeline. For others, it may be an antral follicle count, fertility preservation, IVF planning, treatment for another identified barrier, or a discussion about donor options.
At ProFertility, the aim of testing is not simply to hand you a number. It is to pair certified laboratory data with plain-English clinical guidance, so you can understand what needs attention now and what can wait.
Your fertility story is bigger than one blood result. Give low AMH the attention it deserves, but let a complete assessment and a supportive specialist help shape what comes next.