Understanding Antral Follicle Count (AFC) for Infertility Diagnosis

You are born with a lifetime supply of eggs, and these eggs start to develop once you attain puberty. The eggs are released every month once your first menstrual cycle begins. This way the number of eggs starts to decrease over the years. By the time you reach your menopause, you run out of eggs, and your potential fertility gets exhausted. One study revealed that, before 37 years of age, the Antral follicle count was reduced yearly by 4.8%, and after the age of 37 years was reduced to 11.7% [2].

The antral follicle is a small resting follicle filled with fluid and contains an immature egg. It measures about 2mm to 10mm wide and is visible in an ultrasound. Antral follicles are counted, as well as measured on your cycle days 2, 3, and 5. Your Antral follicle number keeps changing from month to month.

The doctor recommends an antral follicle count test (AFC) when the couple is trying for pregnancy for more than a year and is not able to conceive. Antral follicle count test, along with other tests like serum FSH, E2 test, and AMH test, is done to know the woman's ovarian reserve. This test helps the doctor to understand the reproductive potential of the woman. It assists the doctor in deciding the fertility treatment best suited to your needs.

During the AFC test, if your doctor can see a higher number of antral follicles, it means that you have a greater ovarian reserve. The high ovarian reserve also means that you will respond well to ovarian stimulation drugs given during IVF and IUI treatments. The main goal of ovarian stimulation drugs is to produce multiple eggs for better chances of getting pregnant.

AFC test is a transvaginal ultrasound study, and your doctor does this in the early phases of the menstrual cycle. In this test, your doctor can visualize and can count the number of egg-containing follicles that develop in your ovaries. You can see a clear image of antral follicles projected onto the ultrasound screen in the doctor’s room.

Your fertility doctor will schedule the test on day 3 of your menstrual cycle. The doctor will insert a transvaginal ultrasound probe into the vagina and will examine and count the follicles on each of your ovaries. Testing will take only a few minutes.

Antral follicle count is rightly done on day 3 of the menstrual cycle by transvaginal ultrasound. The doctor will first look at the ovarian volume of the ovaries, and then the number of small antral follicles in both the ovaries is measured. The normal AFC count varies from three to eight antral follicles per ovary.

A low follicle count indicates low fertility and would require a high dose of follicular stimulating hormone levels. The causes of low AFC count are,

• Aging- there is a natural decline of the ovarian reserve due to age.
• Genetic factors and abnormalities- includes Fragile X and other X chromosome abnormalities
• Iatrogenic- means aggressive treatments like radiation for cancer, chemotherapy, or surgery
• Idiopathic- means that there is no apparent cause of low AFC count
• Autoimmune disorders
• Adrenal gland impairment
• Excessive laparoscopic ovarian drilling has been reported to cause premature ovarian failure

Lack of producing a good quality egg is a frequent cause for infertility in women; hence fertility experts check the ovarian reserve (determines the egg supply) as a part of routine fertility evaluation for women. One of the ways to examine the ovarian reserve is by counting the antral follicles, known as the antral follicle count test (AFC Test). check

Adequate follicular count indicates good fertile health, whereas decreased AFC level negatively affects oocyte quality and the likelihood of conception.[3] The low follicular count shows an inability to conceive, and if the women of reproductive age have a lower follicular count, it can cause infertility. Infertility is the failure of a couple to conceive a child after one year of regular, unprotected intercourse. As the woman ages, the number of follicles starts decreasing rapidly, starting in fetal life and continuing until after menopause. [4]

In the case of IVF treatment, antral follicles are good predictors of the number of mature follicles that can be stimulated by drugs for a successful pregnancy. The higher the number of eggs retrieved, the higher the success of your IVF.

Depending on AFC, fertility potential with ovarian stimulation drugs and IVF can be estimated as:

• If you have a high to a very high number of follicles, from 16 to 30, then your ovaries will respond well to ovarian stimulation, and this doubles your chances of pregnancy.
• If your Antral follicle count is low-to-medium, from 11 to 15, it indicates that your ovarian reserve is declining. You may show less response to ovarian stimulation drugs.
• A lower Antral follicle count, from 3 to 6, indicates you have a low ovarian reserve. It does not mean that you cannot conceive, but you may need higher doses of ovarian stimulation drugs while undergoing IVF.
• If you have extremely low AFC, less than 4, then you may not be able to use your eggs for IVF. It is because your ovaries don't release enough eggs that can be retrieved for IVF. In such cases, fertility experts may recommend IVF with donor eggs.

Even if the Antral follicle test is considered as a valuable indicator of your fertility, a low count does not always mean that you will not have a baby. Your fertility specialist will consider a complete fertility checkup and plan the best fertility treatment that suits you.