Q&A: Understanding antral follicle count at age 35
What are antral follicles?
Antral follicles are small, fluid-filled sacs, or follicles, in the ovaries that contain immature eggs. In people with ovaries, the quantity and quality of eggs decline with age, particularly after the age of 35. Therefore, measuring the number of antral follicles (known as antral follicle count) becomes crucial to assess a woman’s ovarian reserve.
These antral follicles are in their final stage of development and are sensitive to follicle-stimulating hormone (FSH), meaning they are the most likely to advance in their development to become pre-ovulatory follicles. Only one antral follicle will fully develop each month to release a mature egg from the ovary during ovulation.
What test is used to measure the number of antral follicles?
A vaginal ultrasound is the best way to accurately assess the antral follicle count (AFC). A small ultrasound probe is inserted into the vagina to visualize the ovaries from multiple angles. Then, the number of antral follicles in each ovary (typically appearing as small black circles) can be counted.
This helps you and your clinic understand the potential for successful egg development and enable the clinic to tailor fertility treatments with all options such as egg donation.
What is a ‘normal’ antral follicle count, and what is considered a low antral follicle count?
We know that female fertility declines with age, but it’s important to know how the antral follicle count also drops as women get older, too. Here is a guide to the average ‘normal’ AFC range, by age:
- 25 to 34 years: 15 is considered a normal AFC for this age group. Anything less than 5 is considered low, whereas anything above 15 is high.
- 35 to 40 years: 9 is considered a normal AFC for this age group. Anything less than 3 is low, whereas more than 12 is considered high.
- 41 to 46 years: Women start approaching menopause slowly during this time, meaning fertility is at its lowest. 4 is considered normal AFC at this age. Anything less than 3 is a low reserve, whereas anything more than 10 is a high reserve.
It’s important to know that your antral follicle count can vary each month during your menstrual cycle. You’ll usually have an AFC performed in the early follicular phase, and talking through your personal test results with your doctor will help you get the clearest picture of your outcome and how to move forward.
What is a good antral follicle count for IVF?
For an IVF cycle, your ovaries are stimulated to produce several mature follicles at the same time. The higher the number of antral follicles, the higher the number of eggs that can be expected to be collected during retrieval. If you’re over the age of 35 and have a low AFC, you’ll likely need higher doses of medication, and cancellation of an IVF cycle is generally more common.
Whilst everyone is different, Clínica Tambre suggests that an antral follicle count between 10 and 15 is what doctors generally look for to indicate a positive outcome.