An age-related nomogram for antral follicle count: an observational study of 3821 women.

Research Question: What is the relationship between antral follicle count (AFC) and chronological age, and what are the expected values for AFC?

Design: This was a retrospective cohort study at a specialist gynaecological ultrasound centre in London, UK. Women presenting to a gynaecology diagnostic unit for investigation of symptoms or routine check-up, and undergoing transvaginal ultrasound (TVUS) examinations, between 1 January 2017 and 22 September 2022 were included in this study.

Results: In total, 8821 TVUS records from 7573 patients were analysed. The relationship between AFC and age was estimated to develop an AFC nomogram independent of the stage in the menstrual cycle. AFC corresponding to the 10, 25, 50, 75 and 90 centiles for each patient and age group were calculated. Both nomogram and condition-specific populations displayed a Gaussian relationship between AFC and age. For the nomogram population (scans n = 4256, patients n = 3821), a peak median AFC of 30 was observed between 21-23 years of age. The AFC distribution of the group with previous ovarian cystectomy (scans n = 534, patients n = 443) was found to be significantly different compared with the nomogram population (P < 0.0001). However, the same did not hold true for those on hormonal contraception (scans n = 566, patients n = 534) (P = 0.43).

Conclusions: An AFC nomogram reporting median and interquartile values for AFC by chronological age across the reproductive years was developed. This is a useful tool for providing counselling for those undergoing ovarian reserve assessments, and can be taken any time in the menstrual cycle, including in women on hormonal contraceptives or who have undergone previous ovarian cystectomy.