When Is the Best Time to Do an Antral Follicle Count (AFC) Scan?

If you’re planning for the future, thinking about egg freezing, preparing for IVF or trying to understand your fertility, you may have come across the term antral follicle count, often shortened to AFC.

It sounds technical, but an AFC scan is simply an ultrasound scan that counts the small follicles visible in your ovaries. These follicles can help clinicians estimate your ovarian reserve, which means the approximate number of eggs remaining in your ovaries.

In this guide, we’ll explain when is the best time to book an AFC scan and why timing can affect the results.

Quick facts:

• An AFC scan is an internal transvaginal ultrasound that counts the small follicles in your ovaries. It is one of the key ways doctors assess ovarian reserve.
• The best time to have an antral follicle count scan for people with regular cycles, is days 2-7 of your menstrual cycle. Day 3 is most commonly recommended, but any day in this window works.
• If your cycles are irregular, you have PCOS, you’re not having periods, or you’ve recently stopped hormonal contraception, different timing guidance applies, and we’ve covered all of it below.
• AFC and AMH are the two gold-standard tests for ovarian reserve. They work best together, and Hertility offers both.

What is an antral follicle count (AFC) scan?

An antral follicle count, or AFC scan, is a specialist internal ultrasound that counts the number of small follicles visible in the ovaries. Think of it as a snapshot of ovarian activity at a specific point in your cycle.

An AFC scan is usually carried out using a transvaginal ultrasound. This involves gently inserting a slim ultrasound probe into the vagina to get a clear view of the ovaries. During the scan, a doctor or sonographer counts the visible antral follicles in each ovary and also assesses the overall appearance of the ovaries and uterus.

Antral follicles are small, fluid-filled sacs, usually measuring around 2-10 mm in diameter. Each follicle contains an immature egg, although the scan does not count the eggs themselves. Instead, the number of visible antral follicles gives an indirect indication of your ovarian reserve, the remaining pool of eggs in the ovaries.

In general, seeing fewer antral follicles may suggest a lower ovarian reserve, while seeing more may suggest a higher ovarian reserve. However, AFC is not a direct measure of egg quality, and it cannot predict your exact chances of getting pregnant naturally.

Your fertility is influenced by many factors, including age, ovulation, egg quality, sperm health, Fallopian tube health, uterine health, hormone levels and medical history. This is why AFC should be interpreted as one part of a wider reproductive health picture, not as a standalone fertility diagnosis.

Why do I need an antral follicle count (AFC) scan?

An AFC scan may be recommended if you are trying to understand your fertility, preparing for fertility treatment or considering fertility preservation, such as egg freezing. Doctors commonly use AFC to help assess:

• Ovarian reserve
• How your ovaries may respond to medication during fertility treatment 
• Whether you may be at risk of a low or high response to ovarian stimulation
• Features that may suggest polycystic ovarian morphology
• Baseline ovarian and uterine health before fertility treatment
• Whether ovarian cysts or other pelvic findings are present

AFC is particularly useful during fertility treatment because it can help fertility specialists plan medication doses and counsel you about likely responses to ovarian stimulation. However, AFC is just one piece of the fertility puzzle. It should not be used in isolation to make big decisions about your reproductive future.

AFC scan vs AMH blood test: what’s the difference?

If you have come across both AFC and AMH while researching fertility testing, you might be wondering whether you need one, both, or whether they tell you the same thing. The short answer is that they both help estimate ovarian reserve, but they do it in different ways.

AMH, or anti-Müllerian hormone, is a blood test that measures a hormone produced by small follicles (eggs)  in the ovaries.

AFC is an ultrasound scan that counts the small follicles (eggs) developing in the ovaries during that cycle. 

Both tests can help estimate how your ovaries may respond to fertility medication during IVF or egg freezing. ASRM guidance notes that AMH and AFC have been shown in multiple studies to be broadly equivalent, although each has strengths and limitations. 

In practice, many clinicians use AFC and AMH together because they provide different but complementary information. AMH gives a hormone-based estimate of ovarian reserve, while AFC gives a visual assessment of the ovaries and pelvic anatomy.

At Hertility, we offer both. AMH is included in our Advanced Hormone & Fertility Test, and our clinical team can arrange a Pelvic Ultrasound Scan that includes an AFC scan as well as assessing the uterus, ovaries and endometrium and interpret both results together, giving you a full, personalised picture of your ovarian reserve rather than a number in isolation.

How is an antral follicle count (AFC) scan done?

An AFC scan is usually performed as a transvaginal ultrasound, which gives a clearer view of the ovaries than an abdominal scan.

A narrow ultrasound probe is covered with a protective sheath and lubricating gel, then gently inserted into the vagina. Most people describe the scan as mildly uncomfortable rather than painful, often similar to the sensation of a smear test.

The sonographer slowly scans each ovary from one side to the other, counting the small follicles visible on screen. These often appear as small, dark, round shapes within the ovary. You may be able to see the ultrasound screen during the appointment, and your sonographer can talk you through what they are seeing. The scan typically takes 10 – 20 minutes.

As well as counting your follicles, at Hertility, our sonographer will also assess:

• Ovarian size and volume
• The uterus and womb lining
• Whether ovarian cysts are present
• Whether fibroids or polyps are visible
• Features that may suggest polycystic ovarian morphology
• Any other pelvic findings that may be relevant to your symptoms or fertility

This means an AFC scan can give more information than follicle count alone.

When is the best time to do an AFC scan?

The best time to have an AFC scan is usually during the early follicular phase of your menstrual cycle.

For most people with regular periods, this means around day 2 to day 7 of the cycle, with cycle day 1 being the first day of proper menstrual flow, not spotting.

This early-cycle timing is preferred because the ovaries are usually in a more “baseline” state. At the beginning of the cycle, several small follicles may be visible in the ovaries. As the cycle progresses, one follicle usually becomes dominant and prepares for ovulation. Once a dominant follicle develops, it can become harder to assess the smaller antral follicles clearly.

Can you have an AFC scan at any time in your cycle?

Yes, in many cases, an AFC scan can still be performed outside the early follicular phase.

Your doctor or clinic may recommend scanning at another point in your cycle if:

• Your periods are irregular or absent
• You are not sure where you are in your cycle
• You need urgent fertility treatment planning
• You are being assessed for pelvic pain, cysts or abnormal bleeding
• You are using hormonal contraception
• Your clinic has a specific scanning protocol
• You are having a general pelvic ultrasound rather than a strict baseline AFC

However, if the main reason for the scan is to get the most accurate baseline AFC, the early follicular phase is usually preferred because it gives the most accurate findings.

If your cycles are irregular, it is worth speaking to our team before booking. They will advise a suitable day for your scan based on your cycle regularity, hormone results or clinical history.

Can an AFC scan diagnose PMOS (PCOS) ?

An AFC scan can show whether your ovaries have a polycystic appearance, but it cannot diagnose PMOS ( formerly know as PCOS) by itself.

In PMOS ( formerly know as PCOS) , the ovaries may contain more of these small follicles than expected because ovulation is not happening regularly. Instead of one follicle developing and releasing an egg, several small follicles may remain visible on the scan. These can look like a “polycystic” pattern, but they are not the same as harmful ovarian cysts.

PMOS ( formerly know as PCOS) is diagnosed using a combination of features, including:

• Irregular or absent ovulation
• Clinical or biochemical signs of higher androgens, such as acne, excess facial or body hair, or raised androgen levels on blood testing
• Polycystic ovarian morphology on ultrasound or high AMH

Some people have polycystic ovaries but do not have PMOS ( formerly know as PCOS) . Others may have PMOS ( formerly know as PCOS) without a classic ultrasound appearance, depending on age, symptoms and hormone profile.

Can contraception affect an AFC scan?

Hormonal contraception may affect ovarian activity, depending on the type used and how long you have been using it. Some forms of contraception suppress follicle development, which can temporarily influence AFC or AMH levels in some people.

If you are using the combined pill, progestogen-only pill, implant, injection, hormonal coil or another hormonal method, tell your clinician before the scan. For the most accurate AFC result that reflects your ovarian reserve without the influence of external hormones. At Hertility, we generally recommend:

Do not stop contraception without medical advice if you need it for pregnancy prevention, symptom control or medical reasons. If you are still using hormonal contraception and need an AFC scan now, the scan can still be performed. Our doctors will interpret the result with the understanding that it may be slightly lower than your true baseline.

What does an AFC scan result mean for my fertility?

Your AFC result is usually given as the total number of visible antral follicles across both ovaries. For example, if six follicles are seen in the right ovary and seven are seen in the left ovary, your total AFC would be 13.

Broadly, a lower AFC may suggest a lower ovarian reserve or a lower likely response to fertility medication. A higher AFC may suggest a better ovarian reserve and a greater likelihood of responding effectively to IVF. However, it is important to understand that a low count does not necessarily mean that you have fertility issues, as other factors such as age, egg quality and lifestyle choices also play a significant role. 

How to prepare for an AFC scan?

Most people do not need to do much preparation before an AFC scan, but your clinic may give you specific instructions.

In general:

• Track the first day of your period so you can book the scan at the right time if needed.
• You are welcome to bring a chaperone for support or if you are feeling nervous. 
• You can dress however you like but you will be asked to undress from the waist down for a transvaginal scan. Some people feel more comfortable wearing a dress or skirt that they can pull up above the waist so you might also consider this.
• If you are unsure whether an empty bladder or full bladder is more appropriate for your scan, we recommend arriving with a full bladder and double-checking with the practitioner before you begin.
• To get to a full bladder with minimum discomfort, we recommend you drink 500ml-1000ml of clear fluid 45 minutes to an hour before the ultrasound, and try not to empty your bladder during this time
• Tell the clinic if you are pregnant, bleeding heavily or using hormonal contraception.
• Let your sonographer know if you have pelvic pain, vaginismus, trauma history or anxiety around internal examinations.

You can ask questions at any time, and you can ask the sonographer to pause or stop the scan if you feel uncomfortable.

Ready to get your AFC scan with Hertility?

At Hertility, we believe fertility information should be clear, personalised and clinically meaningful, not confusing or fear-driven.

Whether you are trying to conceive, planning for the future, exploring egg freezing or simply want to understand your body better, getting the right information early can help you make more informed decisions.

An AFC scan can be a useful part of understanding your reproductive health, but it works best when interpreted alongside your hormones, symptoms, cycle pattern and medical history. 

Hertility’s Private Pelvic Ultrasound includes your antral follicle count alongside a full assessment of your uterus and ovaries, carried out by specialist sonographers and reported by a consultant gynaecologist. 

It’s the most comprehensive pelvic ultrasound available privately and goes beyond just counting follicles. During the scan, your sonographer assesses womb and ovarian health, helping identify findings such as cysts, fibroids, PCOS/PMOS, endometriosis or signs that could explain symptoms like pain, irregular cycles or unusual bleeding, giving you a complete picture of your pelvic health in one appointment.

For the fullest picture of your ovarian reserve, you can pair your AFC scan with Hertility’s Advanced Hormone & Fertility Test which includes AMH alongside up to nine other key hormones, all from an at-home blood test.

Not sure where to start? Take our 5-minute Health Assessment and we’ll guide you to the right next step.

Frequently Asked Questions

What is the best day to have an AFC scan?

The best time is usually between day 2-7 of your menstrual cycle. This is the early follicular phase, when the small antral follicles are easier to count. Count day 1 as the first day of full menstrual flow, not spotting.

Can I have an AFC scan while on my period?

Yes, AFC scans are often done during your period, particularly in the first few days of bleeding. This might feel awkward, but clinics are very used to it. If bleeding is very heavy or you feel uncomfortable, contact your clinic for advice.

Does AFC show egg quality?

No. AFC does not show egg quality. AFC gives information about the number of visible follicles, not the quality of the eggs inside them. Egg quality is strongly linked to age, although other health, genetic and lifestyle factors can also play a role.

This is why two people with the same AFC may have very different fertility outcomes depending on their age, ovulation, sperm health, fallopian tube health, uterine health and overall reproductive picture.

Can an AFC scan diagnose infertility?

No, an AFC scan alone cannot diagnose infertility. It is one part of a broader fertility assessment that may include hormone testing, semen analysis, ovulation assessment, tubal testing, ultrasound and review of your medical history.

Can an AFC scan be done at any time in the cycle?

The scan can be done at any point in your cycle, though many clinics prefer days 2-7 . If you have an irregular cycle or absent periods, this will not prevent us from carrying out the scan.

When should you book an AFC scan if you have irregular periods or PCOS / PMOS?

If your periods are irregular, absent or unpredictable, you may not be able to book an AFC scan neatly between days 2 and 7. In this case, your doctor may advise scanning at any point in your cycle, depending on your symptoms, hormone results and reason for the scan.

Does an AFC scan hurt?

The scan uses a transvaginal probe, which is narrow and covered with a protective sheath and gel. Most people find it mildly uncomfortable at most, comparable to a smear test. If you have vaginismus or significant pelvic pain, let your sonographer know before they begin.

How does the pill affect my AFC result?

Hormonal contraception can mildly suppress the visible antral follicle count during use and in the months immediately after stopping. For the most accurate AFC reflecting your ovarian reserve without the influence of external hormones, at Hertility we recommend waiting 3 full cycles after stopping hormonal contraception before scanning. Your clinician can advise on whether scanning sooner is appropriate for your situation.

References

1. Barad, D.H. et al. (2012). Utility of antral follicle counts in the assessment of ovarian reserve. Current Opinion in Obstetrics and Gynecology, 24(3), 147–151. https://pubmed.ncbi.nlm.nih.gov/22450699/
2. Broer, S.L. et al. (2011). The role of antral follicle counts in the prediction of clomiphene citrate resistance in patients with polycystic ovary syndrome. Fertility and Sterility, 95(3), 1101–1105. https://pubmed.ncbi.nlm.nih.gov/20932507/
3. La Marca, A. & Sunkara, S.K. (2014). Individualisation of controlled ovarian stimulation in IVF using ovarian reserve markers. Human Reproduction Update, 20(1), 124–129. https://pubmed.ncbi.nlm.nih.gov/24077980/
4. Moolhuijsen, L.M.E. & Visser, J.A. (2020). Anti-Müllerian hormone and ovarian reserve: update on assessing ovarian function. Journal of Clinical Endocrinology & Metabolism, 105(11), 3361–3373. https://pubmed.ncbi.nlm.nih.gov/32770239/
5. https://www.asrm.org/practice-guidance/practice-committee-documents/testing-and-interpreting-measures-of-ovarian-reserve-a-committee-opinion-202