What causes low AMH?

AMH levels are determined by the number of developing follicles in your ovaries. The most important determining factor in the number of follicles is age, as ovarian reserve diminishes over time. Ovarian reserve begins to decline in the mid to late 30s, and AMH (and hence ovarian reserve) levels tend to be low in women in their 40s.

Age is not always a factor in low AMH however. Some women continue to have high AMH levels into their 40s, while others have declining AMH levels in their 20s or 30s. This can be due to environmental factors such as cancer treatment, or down to inherited genetic causes. It is important to find out the age of menopause in your family because this is often a good guide to the rate of your own fertility decline.

What are low AMH symptoms?

Whilst there are no obvious obvious symptoms of low AMH, some women notice a reduction or absence of periods. Getting an AMH blood test is the best way of assessing what your AMH levels are.

How does low AMH affect fertility?

Low AMH is not a cause of infertility, but it is an indication of a decreased egg reserve. When there are fewer developing eggs in the ovaries, the chance of a mature and healthy egg being released and fertilised decreases. In age-related low AMH, the quality of the eggs may also be affected, as eggs accumulate mutations over time. This may mean that the chances of abnormal fertilisation and miscarriage are increased.

What if I have low AMH levels?

If you have very low AMH levels, you are likely to respond poorly to the drug doses involved in conventional IVF. However, Natural IVF and Modified Natural IVF can be more a more suitable treatment for those with low ovarian reserve.

Vitanova is part of CREATE Fertility, who are pioneers in offering this IVF treatment as an option for patients who have low ovarian reserve. At Vitanova we will treat any woman under the age of 45 with her own eggs if she is still ovulating and have given many women the chance to try after they have been turned away elsewhere.

High FSH and its relationship with ovarian reserve

Low AMH results generally coincide with high FSH results, and both of these together are an indicator of low ovarian reserve. FSH stands for ‘follicle stimulating hormone’, and is a hormone released by the brain which stimulates the growth and development of follicles within the ovaries. Developing follicles release oestrogen which inhibits FSH, indicating that there are enough viable follicles being ‘recruited’.

When ovarian reserve is low there will not be many follicles recruited, and the levels of oestrogen released will be low. This gives the brain a signal that not enough follicles are developing, and it will subsequently release more FSH. This is why women with a diminished ovarian reserve will have high FSH levels when this is tested on day 3 of the cycle. FSH used to be the most common blood test used to assess ovarian reserve. However, due to the fact that levels can vary from month to month, we now prefer to test AMH results for a more accurate insight into ovarian reserve.