Anti-Müllerian Hormone (AMH) is an important indicator in understanding female fertility. This hormone provides insight into a woman’s ovarian reserve, which refers to the quantity of eggs remaining in her ovaries. Assessing AMH levels helps in evaluating fertility and guiding reproductive planning.
Understanding AMH
Anti-Müllerian Hormone (AMH) is a protein hormone produced by specialized cells within ovarian follicles. These fluid-filled sacs in the ovary contain developing eggs. AMH plays a role in regulating the recruitment of follicles from the resting pool, helping to control which ones mature.
The level of AMH in the blood directly reflects the number of these small, growing follicles. AMH serves as a marker for a woman’s ovarian reserve, indicating the approximate number of eggs she has. AMH measures the quantity of eggs, not their quality, which is influenced by age. AMH levels remain stable throughout the menstrual cycle, making it a convenient test.
Interpreting AMH Levels
AMH levels are commonly measured in nanograms per milliliter (ng/mL) or picomoles per liter (pmol/L). To convert ng/mL to pmol/L, multiply the ng/mL value by 7.14.
An AMH level between 1.0 and 3.0 ng/mL is considered normal, suggesting an adequate egg supply for a woman’s age. Levels below 1.0 ng/mL are low, indicating diminished ovarian reserve. A level of 0.4 ng/mL or lower is severely low, signaling a significantly reduced egg count. AMH levels naturally decline with age, peaking around 25 years old and steadily decreasing thereafter until menopause. For instance, an AMH level normal for a woman in her early 40s would be low for someone in her early 30s.
What Low AMH Signifies for Fertility
A low AMH level indicates diminished ovarian reserve, meaning fewer eggs are available. This can influence the timeframe for natural conception, suggesting a potentially shorter reproductive window. While low AMH points to a reduced quantity of eggs, natural pregnancy is possible, though conception may take longer.
For individuals considering assisted reproductive technologies (ART) such as in vitro fertilization (IVF), low AMH levels can indicate that the ovaries may not respond robustly to ovarian stimulation medications. This can result in fewer eggs retrieved during an IVF cycle. Women with low AMH can still achieve pregnancy through IVF, though chances may be influenced by age. Low AMH signals a need for a proactive approach to fertility planning.
Factors Affecting AMH Levels
Age is the most significant factor influencing AMH levels. As women age, the number of follicles in their ovaries gradually decreases, leading to a corresponding reduction in AMH production. This age-related decline is an expected biological process.
Beyond age, certain medical conditions and treatments can also affect AMH levels. Autoimmune conditions, previous ovarian surgery, and treatments like chemotherapy or radiation can lead to a reduction in ovarian reserve and, consequently, lower AMH. Lifestyle factors such as smoking have been linked to a negative impact on AMH levels. Oral contraceptive use can temporarily suppress ovarian function, but levels typically return to normal after discontinuation.