The physiological sonographic features of the ovary in healthy subjects: a joint systematic review and meta-analysis by the Italian Society of Gynecology and Obstetrics (SIGO) and the Italian Society of Endocrinology (SIE)

Abstract

Purpose There is a lack of uniformity in the definition of normal ovary ultrasound parameters. Our aim was to summarize and meta-analyze the evidence on the topic. Full-text English articles published through December 31, 2020 were retrieved via MEDLINE and Embase. Data available for meta-analysis included: ovarian follicular count, ovarian volume, and ovarian Pulsatility Index (PI) assessed by Doppler ultrasound. Methods Cohort, cross-sectional, prospective studies with a single or double arm were considered eligible. Interventional studies were included when providing baseline data. Both studies on pre- and post-menopausal women were screened; however, data on menopausal women were not sufficient to perform a meta-analysis. Studies on pre-pubertal girls were considered separately. Eighty-one papers were included in the meta-analysis. Results The mean ovarian volume was 6.11 [5.81–6.42] ml in healthy women in reproductive age (5.81–6.42) and 1.67 ml [1.02–2.32] in pre-pubertal girls. In reproductive age, the mean follicular count was 8.04 [7.26–8.82] when calculated in the whole ovary and 5.88 [5.20–6.56] in an ovarian section, and the mean ovarian PI was 1.86 [1.35–2.37]. Age and the frequency of the transducers partly modulated these values. In particular, the 25–30-year group showed the higher mean follicular count (9.27 [7.71–10.82]), followed by a progressive age-related reduction (5.67 [2.23–9.12] in fertile women > 35 years). A significant difference in follicular count was also found according to the transducer’s upper MHz limit. Conclusion Our findings provide a significant input to improve the interpretation and diagnostic accuracy of ovarian ultrasound parameters in different physiological and pathological settings.

Diagnostic et prise en charge du syndrome des ovaires polykystiques

“…La requête doit mentionner un diagnostic clinique possible de SOPK pour qu’une numération des follicules excédentaires soit effectuée. Le nombre normal de follicules par ovaire peut se recouper selon l’âge et la morphologie des ovaires polykystiques; le nombre normal moyen de follicules est de 8 chez les femmes en âge de procréer, avec un volume moyen de 6,1 mL 1 , 18 . On peut observer une morphologie d’ovaires polykystiques chez jusqu’à 25 % des femmes en bonne santé et cela est considéré comme une variante de la normale 19 .…”

Diagnosis and management of polycystic ovarian syndrome

“…Normal follicle numbers per ovary can overlap based on age and polycystic ovarian morphology; the normal mean follicle number is 8 among reproductive-aged females, with a mean volume of 6.1 mL. 1 , 18 Polycystic ovarian morphology may be present in as many as 25% of healthy females and is considered a variant of normal. 19 Patients should be counselled that cysts are immature follicles, which is a normal finding in all ovaries; the number of follicles is what indicates polycystic ovarian morphology.…”