Anti-Müllerian Hormone (AMH) is produced by specialized cells within ovarian follicles, the tiny fluid-filled sacs in the ovaries that contain and nurture developing eggs. In females, AMH plays a significant role in reproductive health, primarily serving as an indicator of a woman’s ovarian reserve. This hormone helps to regulate the growth and development of these follicles. Understanding AMH levels can provide insight into the potential egg supply.
What AMH Measures
AMH levels provide an estimate of the remaining pool of primordial follicles, also known as the ovarian reserve. This measurement is a key indicator of a woman’s reproductive potential, reflecting the quantity of eggs available rather than their quality. A higher AMH level generally suggests a greater ovarian reserve, while a lower level indicates a reduced egg supply. AMH is measured through a simple blood test, and unlike other hormones, its levels remain relatively stable throughout the menstrual cycle, allowing for flexible testing. What constitutes a “low” AMH level is often a relative term, typically compared against age-specific reference ranges.
Primary Causes of Reduced AMH
The most common reason for reduced AMH levels is natural aging, as the ovarian reserve naturally diminishes over time. AMH levels typically begin to decline in the late 20s to early 30s, with a more rapid decrease observed after age 35. By the time a woman reaches her 40s, AMH levels are often significantly lower, reflecting a reduced number of available eggs.
Genetic factors can also influence a woman’s AMH levels and the rate at which her ovarian reserve declines. Some individuals may be predisposed to a smaller initial ovarian reserve or a faster depletion of follicles due to inherited influences. This can lead to lower AMH levels even at younger ages.
Certain medical conditions are associated with reduced AMH. Endometriosis, particularly ovarian endometriomas, can directly impact ovarian tissue and lead to lower AMH levels. Autoimmune diseases, where the body’s immune system mistakenly attacks its own tissues, can also affect ovarian function and result in decreased AMH levels. Examples include autoimmune thyroid disease, type 1 diabetes, rheumatoid arthritis, and systemic lupus erythematosus. Additionally, specific genetic syndromes, such as Fragile X premutation, have been linked to diminished ovarian reserve and lower AMH.
Medical treatments can significantly impact ovarian reserve and, consequently, AMH levels. Chemotherapy and radiation therapy, especially those targeting the pelvic region, can damage ovarian follicles, often leading to an immediate decrease in AMH levels. Ovarian surgeries for conditions like ovarian cysts can also reduce the number of functional follicles and lower AMH levels. The extent of the impact depends on the type and dose of treatment, and the patient’s age at the time of treatment.
While overall health supports reproductive well-being, direct and strong links between specific lifestyle choices and significantly low AMH are not firmly established in scientific literature. Age remains the primary driver of AMH decline. Some studies suggest that factors like unhealthy diet, obesity, smoking, and excessive alcohol consumption may negatively affect ovarian function and potentially contribute to lower AMH levels.
What Low AMH Indicates
A low AMH level primarily indicates a diminished ovarian reserve, meaning there is a smaller number of eggs remaining in the ovaries. While a lower egg count can present challenges in conceiving naturally, it does not mean zero chance of pregnancy. Natural conception is still possible, especially if the remaining eggs are of good quality.
For individuals considering assisted reproductive technologies (ART) like in vitro fertilization (IVF), low AMH can have specific implications. It may suggest a potentially lower response to ovarian stimulation, meaning fewer eggs might be retrieved during an IVF cycle. However, low AMH alone does not predict IVF success rates in younger women, and reasonable live birth rates have been observed even with low AMH values.
AMH levels reflect egg quantity, but they do not predict egg quality. Egg quality is influenced by age, with a natural decline occurring as a woman gets older, particularly after the mid-30s. Therefore, a woman with low AMH can still possess good quality eggs. AMH is considered one piece of a larger fertility picture, and other factors, such as regular ovulation and overall reproductive health, are also important.
Factors Not Directly Affecting AMH
Several factors are commonly misunderstood to directly impact AMH levels, but their influence is either temporary, indirect, or not strongly supported by scientific evidence. Hormonal birth control pills, for example, can temporarily lower AMH levels while a woman is taking them. However, AMH levels typically rebound after cessation of birth control.
While a balanced diet and general health are important for overall well-being, there is limited concrete evidence that specific diets or supplements can significantly increase AMH levels. Some studies suggest certain nutrients like Vitamin D and Coenzyme Q10 (CoQ10) may be associated with AMH levels or egg quality. Lifestyle choices primarily support overall reproductive health rather than directly altering AMH levels.
Stress levels, while impacting overall health, do not have a direct and consistent link to significantly low AMH. Some research suggests a correlation between higher psychological stress and decreased AMH levels in infertile women, particularly chronic stress. Previous pregnancies or breastfeeding also do not directly cause a permanent reduction in AMH levels.