Antral Follicle Count

The eggs that are released by the ovaries are developed in fluid-filled sacs called antral follicles. Within each antral follicle is an immature egg, and during a menstrual cycle, the ovaries release several antral follicles. These antral follicles develop the eggs within them from the surface of the ovaries. When one of these reaches full maturity, the follicle containing the mature egg ruptures and releases the egg, while the rest of the follicles stop developing.  

It is not known how many antral follicles a person’s ovaries have, nor is it known how many are released each cycle. This number varies from one individual to another. Over time, due to the menstrual cycle, these follicles continue to decrease in number. At a point a person no longer has any eggs left in their ovarian reserve. Let us discuss antral follicle count and what it means in terms of fertility.  

Antral Follicle Count

The number of antral follicles their body produces each cycle can give insight into their chances of becoming pregnant. This is true whether pregnancy is through natural conception or through fertility treatments. While natural pregnancy relies on a single mature egg, fertility treatments rely on retrieving multiple mature eggs. As such, it is useful for healthcare practitioners to be aware of the number of antral follicles a person has. This information gives insight into how many eggs could potentially be retrieved after ovarian stimulation. 

There are many factors that affect a person’s antral follicle count. Let us look at a few of the main ones below:

Age

After the age of 35, usually a person produces fewer and fewer antral follicles each cycle. At a point, their ovarian reserve becomes depleted and they no longer menstruate, and neither can they become pregnant. ARTs have enabled people to retrieve and freeze their eggs, until a time they are ready to become pregnant. However, there is a window within which the uterus is capable of carrying a pregnancy to term.

Health

Healthy people produce healthy antral follicles. If a person is not healthy, even without illness, this is reflected in their antral follicles. Tobacco, drugs, alcohol, poor diet, lack of regular exercise, and high stress levels could lead to unhealthy antral follicles. The more ideal situation is one where a person has low levels of stress, gets sufficient sleep, eats a nutritious diet, and exercises regularly. 

Medical History

If a person has a medical history that includes conditions or diseases that had required medical intervention, it affects that individual’s antral follicles. Hypertension, endometriosis, sexually transmitted infections, and polycystic ovary syndrome all have a negative impact on a person’s antral follicles. As well, treatments that involve the use of chemotherapy or radiation can result in the ovaries not producing any antral follicles altogether.

The Antral Follicle Count (AFC) Test

As we had mentioned, the exact number of  antral follicles produced by a person is not known. An AFC test is what is used to determine the number of antral follicles inside a person’s ovaries. It is an estimate rather than an exact count and as a result, the antral follicle count is given as a range rather than an exact figure. 

The test is done using a transvaginal ultrasound which takes images of the ovaries. These images are taken to a specialist for interpretation, and the results given back to a healthcare provider. The healthcare provider compares the result to the normal expected ranges, then determines the treatment protocols that will be used, particularly for assisted reproduction.  

Normal Vs. Abnormal AFC

Each year after the age of 37, the production of a person’s antral follicles decreases by about five percent. This decrease doubles to 10 percent as they get older. Therefore the higher the antral follicle count a person has, the higher the number of eggs retrieved after ovarian stimulation. Let us look at the normal AFC ranges at various stages:  

Follicles and Menstruation

Antral follicles are developed in the follicular phase of the menstrual cycle. This phase lasts two weeks, after which a mature egg is released from an antral follicle. When this occurs, the remaining follicles stop developing. Once the mature egg is released, this phase is called ovulation, it is also the time in which the egg can be fertilized leading to pregnancy. If it is not fertilised, someone gets their period.   

Follicles in Fertility Treatments

In fertility treatments, ovarian stimulation relies on the quantity of antral follicles that are released naturally, but stimulates them using hormones and medications to mature as many of the eggs within the antral follicles.

Intrauterine Insemination (IUI)

IUI treatments typically rely on a person’s natural menstrual cycle which produces one mature egg each time. Ovarian stimulation is sometimes used to stimulate the ovaries, resulting in more than one egg maturing. Should a person’s ovaries develop more than three AFC tests then come in handy before such a treatment to determine the possible impact of ovarian stimulation on antral follicle development. 

In Vitro Fertilization (IVF)

In IVF, AFC results also help medical practitioners to determine the course of ovarian stimulation protocols. Since AFC results are varied, each individual’s treatment plan will be different. For IVF, typically 10 to 15 follicles are required each round, therefore ovarian stimulation aims to facilitate the production of enough eggs for multiple rounds of treatment.    

Summary

Assisted reproductive treatments rely on antral follicle count results in order to determine the course of treatment. The quantity of antral follicles found in a person’s ovaries vary, and a lower count does not necessarily mean that a person will experience challenges conceiving. What is more crucial than the count is the health of the follicles themselves. To find out more about fertility treatments, reproductive health, and family building, contact IVF Fertility Center. Our team of experts is available to assist you at any of our locations across the country.