The Anti-Müllerian Hormone (AMH) test is a simple blood measure used to estimate a woman’s ovarian reserve, which is the remaining quantity of eggs. This hormone is a significant piece of the fertility puzzle, giving a snapshot of the potential number of eggs available for conception. Understanding what a “normal” AMH level means is important, as the result is not a simple yes or no answer to the ability to get pregnant. The interpretation of an AMH level must be placed within the context of a person’s age and overall reproductive health to help individuals and specialists make informed decisions about family planning and potential fertility treatments.
Understanding AMH’s Role in Fertility
AMH is a protein hormone secreted by the granulosa cells that surround the eggs within the ovarian follicles. Specifically, it is produced by the small, growing follicles, known as pre-antral and small antral follicles. The level of AMH detected in the blood directly correlates with the size of this pool of developing follicles. AMH is used as a proxy measurement for ovarian reserve, representing the total number of eggs remaining in the ovaries. A higher AMH level suggests a larger supply of these early-stage follicles, indicating a greater egg quantity. Conversely, a lower AMH level points to a smaller reserve. Because AMH is produced by these early-stage follicles, its level remains relatively stable throughout the menstrual cycle, making it a convenient marker to test.
Interpreting AMH Test Results
AMH levels are typically measured in nanograms per milliliter (ng/mL) or sometimes in picomoles per liter (pmol/L). While the definition of a “normal” range can vary between laboratories, general clinical consensus has established reference ranges to categorize ovarian reserve.
Optimal and Average Levels
For women of reproductive age, an optimal AMH level is frequently cited as falling between 1.5 ng/mL and 4.0 ng/mL. Other reputable sources suggest a slightly broader average range of 1.0 ng/mL to 3.0 ng/mL. Levels within this optimal range suggest a sufficient ovarian reserve and a favorable response to potential fertility treatments like in vitro fertilization (IVF).
Low Levels
An AMH level considered low is typically below 1.0 ng/mL, suggesting a diminished ovarian reserve. Very low levels, often under 0.5 ng/mL, indicate a significantly reduced egg count, which may require more aggressive fertility planning. A low AMH does not eliminate the possibility of natural conception, but it does suggest a lower egg quantity.
High Levels
A high AMH level is generally defined as being above 4.0 ng/mL. While a high level suggests a large egg supply, levels significantly above this threshold, such as 5.0 ng/mL or higher, may raise suspicion for Polycystic Ovary Syndrome (PCOS). Women with PCOS often have an excessive number of small follicles, leading to this elevated reading. High AMH levels are also associated with an increased risk of Ovarian Hyperstimulation Syndrome (OHSS) during ovarian stimulation procedures.
Factors Influencing AMH Levels
The most significant factor influencing AMH levels is age, as ovarian reserve naturally declines over time. AMH levels typically peak in a woman’s mid-twenties and then gradually decrease, reflecting the continuous, irreversible loss of eggs. This age-related decline means a specific AMH number must always be interpreted in the context of the patient’s age. For example, a level of 1.5 ng/mL might be considered low for a 30-year-old but entirely expected for a 40-year-old.
Certain medical conditions and treatments can also significantly affect AMH measurements. Conditions like severe endometriosis, particularly ovarian endometriomas (cysts), can negatively impact the surrounding ovarian tissue, potentially leading to lower AMH levels. Medical treatments such as chemotherapy or radiation therapy for cancer are known to be toxic to the ovaries, often causing a rapid drop in AMH.
Some medications and lifestyle factors can temporarily suppress AMH readings. Hormonal birth control, for instance, can artificially lower AMH levels by up to 30% while in use, suggesting the test should ideally be performed after discontinuing contraception. Smoking has been consistently linked to lower AMH levels and a diminished ovarian reserve. Low Vitamin D levels are also associated with reduced AMH signaling, which can impact the test result.
AMH Limitations and Complementary Testing
While AMH is an excellent marker for egg quantity, it does not predict egg quality. Egg quality, which is the genetic health of the egg, is primarily determined by age and is the most significant factor in the likelihood of a successful pregnancy. A young woman with a low AMH still has a higher chance of conceiving than an older woman with the same low AMH reading. AMH also cannot predict immediate pregnancy success or overall fertility on its own, as it does not account for other factors necessary for conception, such as healthy fallopian tubes, a receptive uterus, or sperm quality.
To gain a more complete picture, specialists often rely on complementary testing. The Antral Follicle Count (AFC) is a count of the small follicles seen via transvaginal ultrasound, providing a physical, real-time assessment of the ovarian reserve. Another common test is the Follicle-Stimulating Hormone (FSH) test, typically measured early in the menstrual cycle, which indicates how hard the body is trying to stimulate follicle growth. A high FSH level is often seen alongside a low AMH, confirming a diminished reserve. If AMH results are concerning, consulting a reproductive endocrinologist is the recommended next step for a comprehensive evaluation.