An Antral Follicle Count (AFC) is a diagnostic tool used in reproductive health to assess a woman’s ovarian reserve. This test involves measuring the number of small, fluid-filled sacs, known as antral follicles, that are visible on the ovaries. These follicles each contain an immature egg, and their count provides insight into the remaining egg supply. The primary role of AFC is to offer a foundational understanding of a woman’s reproductive potential.
Purpose of Antral Follicle Count
An Antral Follicle Count is performed to assess ovarian reserve, which indicates the quantity of eggs remaining in the ovaries. This assessment helps clinicians predict a woman’s potential response to various fertility treatments, such as in vitro fertilization (IVF). A higher AFC generally suggests a better ovarian reserve and a higher likelihood of responding well to fertility medications used for ovarian stimulation.
The AFC also helps in evaluating overall fertility potential, offering valuable insight into a woman’s ability to conceive naturally. For those undergoing IVF, the AFC can guide specialists in tailoring treatment plans, including adjusting medication dosages and duration to optimize the number of mature eggs produced. This information assists healthcare providers in making informed decisions about the most suitable assisted reproduction strategies.
How Antral Follicle Count is Measured
An Antral Follicle Count is performed using a transvaginal ultrasound, a common and routine procedure. During this examination, a specialized ultrasound probe is gently inserted into the vagina. This probe emits sound waves that create clear images of the ovaries on a screen.
The sonographer or fertility specialist carefully examines each ovary, identifying and counting the small antral follicles. These follicles typically measure between 2 to 10 millimeters in size. The scan is commonly timed during the early follicular phase of the menstrual cycle, often between day 2 and day 5, when these follicles are most visible and measurable. The total count is the sum of the antral follicles identified in both ovaries.
Understanding Antral Follicle Count Results
Different AFC ranges provide general indications about ovarian reserve and potential fertility outcomes. A total AFC typically ranges between 3 and 30, with many women having between 12 and 24 follicles. A count of less than 5 follicles is generally considered low, suggesting a diminished ovarian reserve and potentially a lower response to ovarian stimulation during fertility treatments, which may require higher medication doses.
An AFC between 9 and 21 is often considered intermediate to normal, with varying responses to ovarian stimulation. A count of 15 or more, or generally above 10, indicates good ovarian reserve and typically correlates with better fertility outcomes, including a higher likelihood of producing more mature eggs during IVF. For IVF, a target range of 10 to 15 follicles is often aimed for to increase the chances of successful fertilization. However, AFC is only one piece of the fertility assessment and should be interpreted alongside other factors like a woman’s age, egg quality, and other hormone levels, such as Anti-Müllerian Hormone (AMH).
Factors Affecting Antral Follicle Count
The most significant factor influencing a woman’s Antral Follicle Count is age, as ovarian reserve naturally declines over time. For instance, women aged 25-34 typically have an AFC ranging from 10 to 13 follicles, while those aged 35-40 usually have 8 to 10 follicles. By age 41-46, the expected AFC can decrease to 5 to 7 follicles.
Beyond age, other influences can affect AFC. Genetics play a role in an individual’s ovarian reserve. Certain medical conditions, such as Polycystic Ovary Syndrome (PCOS), can lead to a high AFC due to an increased number of small antral follicles, though this does not always translate to viable eggs. Previous ovarian surgery, endometriosis, or medical treatments like chemotherapy and radiation can also negatively impact the AFC. Lifestyle choices, including Body Mass Index (BMI), tobacco, drug, and alcohol use, may also contribute to the number and quality of follicles.