The relationship between hormonal birth control and Anti-Müllerian Hormone (AMH) levels is a common concern for individuals considering their reproductive futures. AMH has become a standard measure in fertility assessments, leading to questions about whether long-term contraceptive use might artificially lower this result. While hormonal birth control does affect the immediate measurement of AMH, the current scientific understanding confirms this effect is temporary. The impact is primarily on the hormone’s circulating levels while the medication is active, not on the overall ovarian reserve.
Understanding Anti-Müllerian Hormone and Ovarian Reserve
Anti-Müllerian Hormone is a protein produced by the granulosa cells surrounding the small, immature follicles within the ovaries. These follicles are in the preantral and small antral stages of development, typically measuring less than 4 millimeters in diameter. The level of AMH found in a person’s blood is therefore used as an indirect measure of the size of the remaining pool of eggs and follicles, referred to as the ovarian reserve.
A higher AMH level generally indicates a larger supply of remaining follicles, while a lower level suggests a diminished reserve. Because AMH production is relatively constant throughout the menstrual cycle, unlike other reproductive hormones, it has become a valuable and convenient tool in fertility assessments. Clinicians use AMH testing to help estimate a person’s potential response to fertility treatments, such as in vitro fertilization (IVF), and to gauge the general pace of ovarian aging.
Temporary Suppression: How Hormonal Birth Control Affects AMH Levels
Hormonal birth control, particularly the combined oral contraceptive pill, temporarily lowers the measured AMH concentration in the blood while it is being used. This is not due to a physical depletion of the egg supply but rather the way the contraceptive works to suppress the reproductive system. Combined oral contraceptives introduce synthetic estrogen and progesterone, which inhibit the release of the pituitary hormones, Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH).
FSH is necessary to stimulate the growth of the small follicles that produce AMH. By suppressing the body’s natural signaling pathway, hormonal contraception reduces the number of actively recruited and growing follicles. This reduction leads to a corresponding decrease in AMH secretion, often resulting in AMH concentrations up to 30% lower than in non-users, though the underlying primordial follicle pool remains untouched.
Assessing Long-Term Effects on Ovarian Reserve
A primary concern for many users is whether years of hormonal birth control use might permanently deplete the ovarian reserve, leading to lower AMH levels after stopping the medication. The scientific consensus is that hormonal contraception does not cause a permanent reduction in ovarian reserve. The temporary suppression of AMH seen during use is fully reversible once the medication is stopped.
Studies tracking individuals who used hormonal birth control for long periods have shown that their AMH levels rebound after discontinuation. One study found that after stopping combined oral contraceptives, AMH levels increased by an estimated average of 53%, returning to a stable baseline within about two months. The long-term decline in ovarian reserve is governed by biological age, as the pill pauses the measurement of AMH but not the natural aging process of the ovaries.
Interpreting AMH Results While Using or After Stopping Birth Control
Because hormonal birth control temporarily lowers AMH levels, the timing of the test is important for obtaining the most accurate reflection of the true ovarian reserve. An AMH result taken while on the pill may appear artificially low, potentially causing unnecessary alarm. If a person currently using hormonal contraception receives a surprisingly low AMH result, it is often recommended to stop the medication and retest.
To allow AMH levels to return to their true baseline, healthcare providers typically advise a “washout” period after discontinuing hormonal birth control. Testing should ideally occur after two to three months, or after the second natural menstrual cycle, to ensure the reproductive axis has fully reactivated. However, if a person on hormonal birth control receives an AMH result that is already considered high or normal for their age, that result can generally be interpreted as a favorable indicator of ovarian reserve without the need for immediate retesting.