Guide to Antral Follicle Count

Within ovaries, you will find follicles, which are small sacs filled with fluid. This fluid helps the eggs mature. In a regular ovulation cycle, the follicle sack bursts, and the egg reaches full maturation and is released. 

When a female is born, her ovaries contain all the potential eggs she will have but some of these eggs are lost naturally or through atresia. During this time, immature follicles that are unable to release an egg are reabsorbed back into the body. The more we age the faster this process takes. 

These follicles are important in the IVF process. They go through different stages over their lifetimes, one of them being the antral follicle stage. This article will delve into this important stage in fertility – the Antral Follicle Count. 

Key Takeaways

• Follicles develop in groups during the menstrual cycle, but ultimately only one reaches full maturity and releases an egg during each cycle.
• Age is a major determinant of how many follicles grow and become viable in each cycle, but certain medications can stimulate follicles and increase the number reaching maturity at once.
• Antral follicles are small, fluid-filled sacs with eggs inside them that grow on the outside of ovaries, eventually rupturing and releasing an egg during ovulation.

What Is an Antral Follicle Count?

Antral follicles are small, fluid-filled sacs outside the ovaries that hold immature eggs also known as oocytes. Every month, several follicles, which develop in groups start to mature but only one egg succeeds. The successful mature egg is released during ovulation.

The antral follicles that develop during any given menstrual cycle differ from person to person, typically depending on age. This means the older one grows the fewer the follicles produced and the lesser the chances of becoming pregnant.  

One’s antral follicle count or AFC is a great indicator of conception or pregnancy. One study showed how this count is an accurate marker for ovarian reserve (how many eggs are left), which is essential to those who need help conceiving. 

Patients who need help conceiving are concerned about their ovarian reserve, or how many eggs are left in their ovaries. Diminished ovarian reserve, whether caused by natural aging or by the approach of premature menopause, is one of the leading causes of infertility in women. 

It can also be a big factor in IVF's likelihood to work for a patient. Understanding how the ovaries work and how your ovarian follicles affect your chances of IVF success is a key part of choosing a fertility treatment plan with your doctor.

The Antral Follicle Count (AFC) Test

The antral follicle count (AFC) is a common test done to determine follicles in the ovaries or one’s ovarian reserve. It is also a good measure for confirming a woman’s fertility outside of the quality of eggs or physical well-being.  

With this test, IVF Specialists like  Ivy Fertility can diagnose diseases like polycystic ovary syndrome (PCOS) and provide insight into how successful an assisted reproduction technology treatment will be. 

The AFC test is a transvaginal ultrasound done by a fertility specialist. The ultrasound wand is inserted into the vagina and captures images of the ovaries themselves. It is a quick and painless test performed on the third day of your menstrual cycle. 

These ultrasound images give a better look at the development of antral follicles and offer a rough estimate (not an exact number) of an individual’s AFC. 

What Is A Normal Antral Follicle Count?

When doing the test, the specialist determines what is a normal or abnormal AFC. Most women have between 12 and 24 follicles. Therefore, a “normal” AFC ranges between 3 and 30 follicles but this can vary greatly depending on several factors, including age and genetics.

The total AFC is the sum of the antral follicles in both ovaries. It’s normal for the count to vary between ovaries. This uneven distribution is no cause for concern as long as the total count is within the normal range.

Normal Antral Follicle Count By Age:

Age is a key determinant of the AFC but this also varies based on an individual’s overall health and the number of healthy follicles they have in the beginning.  AFC has been shown to decrease with age, with an accelerated decline in the late 30s. 

A study conducted on women aged 25-46 years found an average AFC decline of around 5 percent for individuals under the age of 37, with that decline increasing to almost 12 percent in the following years.

• 20-24 years: 12-30 follicles
• 25-34 years: 13-25 follicles
• 35-40 years: 10-15 follicles
• 41-45 years: 3-10 follicles
• 46+ years: 0-3 follicles

Does Low Antral Follicle Count Result in Infertility?

While a low AFC indicates a lower ovarian reserve, this doesn’t automatically result in infertility. Women with low AFC have been known to conceive, especially with the help of treatments like IVF. Though you can’t naturally increase your AFC count, lifestyle changes can improve the overall health of your eggs. 

In contrast, women with Polycystic Ovary Syndrome (PCOS), can have a high AFC because PCOS can cause an increase in small antral follicles. However, this doesnt translate to egg viability. 

How Many Follicles Do You Need for Fertility Treatments?

One’s follicle count can play a key role in the success of fertility treatments like IVF.  For such treatments, follicles are stimulated to reach maturity so that there’s an increase in the likelihood of successful fertilization.

Unlike intrauterine insemination (IUI ) treatments that only need one healthy follicle for a pregnancy to occur, IVF treatments require a higher number of follicles, aiming for the 10 to 15 range. Although an IVF round requires these numbers, successful treatments are possible with numbers outside this range. 

Because the IVF process involves extracting eggs from the ovaries before fertilization, there is no associated risk with multiple pregnancies like in an IUI treatment cycle. This allows specialists to stimulate larger groups of follicles at a time, providing a larger number of viable eggs to fertilize or freeze for future rounds of treatments.

One study found individuals with higher AFC numbers were more successful in their IVF cycles overall, but also found AFC data could provide valuable insight for how to proceed with fertility treatments regardless of how many follicles were present during a given menstrual cycle.

Bottom Line

The Antral Follicle Count rtemains one of the best ways to assess an individual’s fertility, but a low or declining count does not necessarily mean a healthy pregnancy is impossible. Many individuals have become pregnant naturally despite tests indicating a declining AFC. 

Assisted reproduction technology treatments like IVF have proven to be very successful for many couples and individuals struggling with fertility difficulties. If you are trying to become pregnant or are planning to in the future, an AFC test could provide valuable insight into your best steps forward toward those goals.