Use this tool to interpret antral follicle count by age. It gives an age-adjusted percentile, a plain-language meaning, and suggested re-test timing.
How the percentile is estimated
- Reference curve: we approximate a smoothed distribution of antral follicle count by single-year age from late teens to mid-40s. The median AFC declines with age and the spread narrows modestly across cohorts described in ovarian reserve literature (La Marca & Sunkara, 2014).
- Percentile math: your AFC is compared to the age-matched distribution to estimate a percentile (0–100). This frames the result as below average, about average, or above average for your age. Percentiles are educational and not diagnostic (Broer et al., 2011).
- Plain language: we convert percentile bands into short statements so people can screenshot or share for clinic discussions.
Estimated egg-yield band
The egg-yield line maps AFC to typical oocyte numbers retrieved in antagonist protocols (illustrative ranges). Actual response varies with dose strategy, AMH, body size, and clinic protocols (Broer et al., 2011; La Marca & Sunkara, 2014).
Advanced inputs and caveats
- Cycle day: AFC is ideally measured on cycle day 2–5 in the early follicular phase (ASRM Committee Opinion, 2020).
- Hormonal contraception: combined pills, ring, patch, and some hormonal IUDs can transiently suppress visible follicles on ultrasound; we display a caution rather than altering the count (ASRM, 2020).
- PCOS context: polycystic ovary syndrome can inflate AFC without guaranteeing egg quality; interpretation should consider the whole picture (International PCOS Guideline, 2018/2023 update).
- Unilateral ovary/limited views: if only one ovary is seen or present, AFC may be lower yet appropriate for anatomy. Clinical context matters.
When to re-test
- Typical interval: 6–12 months for routine tracking when no urgent plans are in place.
- Sooner: 3–6 months if AFC is very low or there is a time-sensitive treatment plan. Your clinician may advise different timing.
Limitations
- Percentiles are derived from aggregated reference data and may not match a specific clinic population.
- Operator and ultrasound machine differences affect counts, especially for small follicles.
- AFC reflects quantity more than quality; age remains the strongest driver of egg and embryo competence.
- Use AFC together with AMH, menstrual history, and clinical context when making decisions.
- La Marca A, Sunkara SK. Hum Reprod Update. 2014 — framework for individualizing stimulation using ovarian reserve markers, with AFC by age.
- Broer SL et al. Hum Reprod Update. 2011 — meta-analysis linking AFC and AMH to poor/high ovarian response.
- ASRM Committee Opinion, 2020 — testing and interpretation of ovarian reserve, including preferred timing for AFC.
- International PCOS Guideline. 2018 with updates — diagnostic context and implications for follicle counts.
How to use this calculator
- Enter your age and your antral follicle count from ultrasound.
- Optional: add cycle day, hormonal contraception, and whether you have a PCOS diagnosis.
- Read your age-adjusted percentile and a short interpretation.
- See an estimated egg-yield band for a typical retrieval and when to consider re-testing.
Educational only, not medical advice. Discuss results with your clinician, especially if planning IVF or egg freezing.
Frequently asked questions
What is antral follicle count (AFC)?
AFC is the number of small resting follicles seen on ultrasound, often measured early in the cycle. It is one snapshot of ovarian reserve.
Which cycle day is best for AFC?
Many clinics measure AFC in the early follicular phase. If your scan was on a different day, interpretation can vary and repeat measurement may be suggested.
Do contraception or PCOS change AFC?
Hormonal contraception and PCOS can influence AFC readings. The calculator lets you note these so the context is clear in your result.
How often should I re-test?
For most people, repeating AFC in 6–12 months is reasonable. If you are planning treatment sooner or your result was unexpected, discuss earlier re-testing with your clinician.
Does AFC predict natural fertility?
AFC is more useful for treatment planning, such as expected response to ovarian stimulation. It does not predict the exact time to pregnancy on its own.
How does AFC compare with AMH?
AFC and AMH both reflect ovarian reserve. They often correlate, and looking at both can help build a clearer picture for decision-making.