What is an Antral Follicle Count?

An Antral Follicle Count (AFC), also known as a resting follicle count, tallies the number of primordial egg follicles within the ovary per menstrual cycle. Each antral follicle has the potential to develop into a viable egg for fertilization. Women undergoing fertility treatment have an AFC level test to determine the likelihood of a future pregnancy through in vitro fertilization (IVF). A woman of average fertility has a count is between 15 and 20 follicles per cycle, and any result under five indicates a greater degree of difficulty becoming pregnant.

The antral follicle count test is done on an outpatient basis. A transvaginal ultrasound creates an image of the ovary, and this image is then carefully screened for any visible antral follicles. Each follicle is marked by hand on the scan, and the total will be noted in the medical charts.

Testing for the antral follicle count can be done on any day of the menstrual cycle. Some fertility doctors may use it to predict the number of a woman's remaining fertile years. A follicle count of over 20 would indicate a woman has 15 to 20 fertile years remaining. If a woman has a count of ten or below, she possibly has about 13 years before menopause begins.

A woman’s ovarian reserve, the amount of potential eggs left in her ovaries, can be estimated with an antral follicle count. More available eggs in reserve indicates a greater possibility of pregnancy after fertility treatment. Fertility specialists usually recommend daily injections of a follicle-stimulating hormone (FSH) to promote the production of eggs ready for fertilization.

Women with a low AFC may need larger amounts of FSH injected to produce the same amount of eggs as a woman with a high count. Some women may not be able to produce enough eggs even with large doses of FSH. These women may decide to use an egg donor as part of the IVF process.

Increasing the dosage of FSH can cause unpleasant side effects. A number of women may develop a mild case of a ovarian hyperstimulation syndrome (OHSS). Abdominal pain and a small weight gain are common side effects of injecting FSH. Gastrointestinal complaints, such as diarrhea, nausea, and vomiting, may accompany the increased levels of FSH circulating in the body.

Some women may experience a severe OHSS reaction after injecting FSH to improve an antral follicle count. Severe OHSS can cause extreme weight gain and abdominal bloating from acites, a buildup of internal fluids within the abdominal cavity. Treatment for this painful condition is limited to bed rest and the administration of intravenous (IV) fluids. Pain medication may be prescribed until the abdominal swelling is reduced.