Checking one’s “egg count” is a medical process that assesses Ovarian Reserve, which reflects the quantity of remaining eggs and the potential reproductive lifespan. This evaluation does not determine the exact number of eggs a person has, but rather estimates the size of the pool of immature follicles available for development. Understanding this reserve is an important part of fertility planning, offering insight into the time horizon for conception, whether naturally or through assisted reproductive technologies. Doctors rely on a combination of blood tests for hormonal markers and specialized ultrasound imaging to gather a comprehensive assessment.
Hormonal Markers of Ovarian Reserve
The primary blood test used to gauge ovarian reserve is the measurement of Anti-Müllerian Hormone (AMH). This hormone is produced by granulosa cells within the small, growing follicles, making it an indirect indicator of the remaining egg supply. AMH levels are generally stable throughout the menstrual cycle, meaning the blood test can be performed at any time.
A higher AMH level typically correlates with a larger ovarian reserve, while a low level suggests a diminished supply of eggs. Levels below 1.0 ng/mL may be considered low, indicating a potentially shorter window for conception, though normal ranges are age-dependent. Conversely, very high AMH levels, often exceeding 3.0 ng/mL, can indicate Polycystic Ovary Syndrome (PCOS), which may prompt tailored treatment plans.
Follicle-Stimulating Hormone (FSH) and Estradiol (E2) are typically measured early in the menstrual cycle, often on Day 3. FSH is released by the pituitary gland to prompt follicles to grow and mature. If the ovaries are becoming less responsive due to a smaller reserve, the brain releases higher levels of FSH to compensate.
An elevated FSH level (generally above 10 IU/mL) suggests the ovaries require more stimulation, pointing toward a lower ovarian reserve. Estradiol (E2) is also measured because an abnormally high level on Day 3 can artificially suppress the FSH reading, masking a potential issue. Doctors seek a low Day 3 Estradiol level, ideally below 50 pg/mL, to ensure the FSH reading is accurate and reflective of the ovarian response.
Ultrasound Assessment: Antral Follicle Count
The physical complement to hormonal testing is the Antral Follicle Count (AFC), which uses transvaginal ultrasound imaging to count small follicles in the ovaries. Antral follicles are fluid-filled sacs, measuring between 2 and 9 millimeters, that contain immature eggs. These are the resting follicles recruited each month that are large enough to be visualized.
The procedure is usually performed early in the menstrual cycle, between days 2 and 5, to count the baseline population before a dominant follicle takes over. The healthcare provider systematically scans both ovaries, counting every visible antral follicle. The total sum provides a snapshot of the current ovarian reserve, with a total AFC between 10 and 20 often considered a normal finding.
The resulting AFC number is a direct functional measure, indicating the pool of follicles available to respond to hormonal signals. For individuals undergoing in vitro fertilization (IVF), the AFC is valuable because it helps predict how the ovaries will respond to stimulation medications. A low AFC, sometimes defined as five to seven or fewer follicles, indicates a diminished ovarian reserve and a likely lower yield of eggs during retrieval.
Interpreting Results and Fertility Planning
A doctor assesses ovarian reserve by synthesizing the results from the AMH blood test, the Day 3 FSH/Estradiol levels, and the Antral Follicle Count. No single test result determines future fertility alone; these metrics provide a collective estimate of the remaining egg quantity. The strong positive correlation between AMH levels and AFC means these two markers often align, offering a reliable prediction of how the ovaries may respond to stimulation.
The collective data is used to counsel patients on their reproductive time horizon, as a lower ovarian reserve suggests a need for more immediate planning. For individuals planning egg freezing, AMH and AFC help determine the appropriate medication dosage and the expected number of eggs retrieved. Higher AMH and AFC values typically suggest a better response and potential for a greater number of retrieved eggs.
These tests measure egg quantity, but they do not assess egg quality, which remains the most significant factor affecting the chance of a healthy pregnancy. Egg quality is directly tied to age. A young person with a low ovarian reserve still typically has better quality eggs than an older person with a comparable low count. Therefore, interpretation of the results always takes the patient’s age into account to guide decisions regarding fertility treatments or preservation options.