Ultrasound Characterization of Disordered Antral Follicle Development in Women with Polycystic Ovary Syndrome

Abstract

Context: The mechanism of oligo-anovulation in polycystic ovary syndrome (PCOS) is unknown.

Objectives: To evaluate follicular and endocrine characteristics of anovulatory and sporadic ovulatory cycles in women with PCOS.

Design: Prospective, longitudinal study.

Setting: Academic clinical research unit.

Participants: 26 reproductive-aged women (18-38 years) with PCOS, observed during natural anovulatory (PCOS-Anov; n = 12) and sporadic ovulatory cycles (PCOS-Ov; n = 14), and 12 controls.

Interventions: Transvaginal ultrasonography and venipuncture were performed every other day for 4 to 6 weeks in women with PCOS or at 1 interovulatory interval in control subjects.

Main outcome measures: Follicle number and diameter (ie, ≥2 mm) were quantified at each visit. Individual growth profiles were assessed for all follicles that grew to ≥7 mm. Blood samples were assayed for follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone.

Results: Follicular excess, or heightened follicle number versus controls, was observed across anovulatory and sporadic ovulatory cycles in PCOS. In PCOS-Anov, follicles emerged cyclically in some women (6/12; 50%) and continuously in others (6/12; 50%), then grew to a mean maximum diameter of 7.2 mm and regressed within 4.7 days. In PCOS-Ov, follicles mostly emerged cyclically as part of a cohort and dominant follicles showed normal growth to ovulation-albeit mean and maximum luteal progesterone concentrations were significantly lower versus controls.

Conclusions: Follicle growth and regression were detected on ultrasonography amidst perpetual follicular excess in PCOS. Documentation of continuous follicle recruitment and turnover, the absence of persistence, and altered luteal progesterone following sporadic ovulation, provide formative data on antral follicle development in PCOS.

Keywords: anovulation; ovarian follicle; polycystic ovary syndrome; ultrasonography.