P-624 Description of antral follicle count in a population of healthy French women based on age, ultrasound technique, and clinical factors
Authors: Abdennebi I , Koren N , Bechim S , Vernet T , Pasquier M , Goro S , Levaillant J  M , Massin N 
Published: July 2024

Abstract

Study question
How is the age-specific reference range for antral follicle count in healthy French women correlated with clinical markers ?

Summary answer
AFC declines linearly with age is correlated with weight, hormonal contraception, cycles duration, but not BMI, smoking or infertility history.

What is known already
AFC is related to the number of primordial follicles within the ovaries and is a widely used marker for baseline assessment of ovarian reserve, but there are no standardized norms for AFC, and major differences between the nomograms published in recent years notably due to the improvement of ultrasound techniques. Moreover, most published data are based on infertile women. Several factors are postulated to have influence on AFC of which ethnic origin, yet the largest cohorts published recently are Asian and therefore do not apply to a Caucasian population.

Study design, size, duration
In this retrospective study we used data from 640 women who had undergone a Fertility Check Up in our center, from 2018 to 2023. This concept, unique in France, offers all women of reproductive age who wish to undergo a complete ultrasound examination to check for infertility risk factors, whatever their parental plans.

Participants/materials, setting, methods
640 healthy French women undergoing a Fertility Check Up were recruited. All participants completed a questionnaire about demographics, medical and surgical history, obstetrical records, familial medical history and any usage of hormonal contraception. AFC was conducted via transvaginal ultrasound using a three-dimensional acquisition, by one of three trained operators, utilizing a Voluson E10 ultrasound machine (GE Healthcare). Operators employed either the sonoAVC option (semi-automatic technique) or a manual two-dimensional counting of the acquired 3D-dimensional volume.

Main results and the role of chance
The distribution of AFC by age were modelized by a numerical and a graphic nomograms. AFC demonstrated a linear decline with a decrease of 1.11 follicle (IC95% 0.98 - 1.24) per year of age. Age accounted for 12.5% of the variation (R2) in AFC. Linear regression analysis showed a significant negative correlation between AFC and women’s weight (p = 0.02), but not with BMI (p = 0.23), and a significant impact of hormonal contraception (p = 0.001), with an overall reduction of 6.6 follicles in AFC compared with the women without any hormonal contraception (IC95% 4.6 - 8.6). Short menstrual cycles were associated with lower AFC (p &lt; 0.001), when long cycles and amenorrhea were significantly associated with higher AFC (p &lt; 0.01). There was no impact of age of menarche, smoking, family history of POI, or of a history of infertility of more than one year. Multivariate analysis showed that AFC was significantly higher with 3D-manual versus automated-3D follicular counting, the difference averaged 3.59 follicles, reducing as AFCs became smaller.

Limitations, reasons for caution
We present data from Caucasian women using our ultrasound machines, but in practice, each sonographer must familiarize himself with the capabilities of his own machine. Furthermore, our study does not answer the question of AFC evolution over time, for a given patient.

Wider implications of the findings
Some questions remain unanswered, including the longitudinal trajectory of AFC within an individual and the impact of ethnic origin. Future longitudinal studies reporting the evolution of AFC with age and involving women of diverse ethnic backgrounds are needed. Ultimately, this study highlights the impact of ultrasound equipment and technique.

Trial registration number
Not applicable