Objective: The aim of this study was to characterize the ovarian primordial and nongrowing follicle number according to the Stages of Reproductive Aging Workshop (STRAW) staging system as defined by menstrual cycle characteristics.
Methods: Normal ovaries were collected from 63 women (age 26-52 y) undergoing oophorectomy for benign indications. Before surgical operation, each participant completed a detailed questionnaire collecting information regarding menstrual cycle characteristics and was classified by bleeding patterns into STRAW stages −4, −3, −2, and −1. A single ovary was selected for the determination of ovarian primordial and total nongrowing follicle number using a validated fractionator/optical disector method. A subset of the participants (n = 43) underwent transvaginal ultrasound examination for the determination of the ovarian antral follicle count and serum measurements of follicle-stimulating hormone, estradiol, antimüllerian hormone, and inhibin B. All measurements were obtained within 2 weeks of surgical operation, irrespective of cycle day.
Results: Significant differences were identified in ovarian primordial (P < 0.0001) and nongrowing follicle (P < 0.0001) counts across the STRAW stages. In post hoc testing, the differences in primordial follicle counts were significant between each of the STRAW stages. Significant differences were also identified in serum levels of antimüllerian hormone, follicle-stimulating hormone, and ovarian antral follicle count across the STRAW stages.
Conclusions: Progression through the STRAW stages as defined by menstrual cycle characteristics is associated with progressive and significant decreases in the ovarian primordial follicle number.
Progression through the STRAW stages of reproductive aging as defined by menstrual cycle characteristics is associated with progressive and significant decreases in the ovarian primordial follicle number. This finding represents an important step in the validation of the STRAW staging system.
From the 1Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK; and 2Seattle Reproductive Medicine, Seattle, WA.
Received August 4, 2011; revised and accepted October 3, 2011.
Funding/support: This study was supported by HR04-115 (Oklahoma Center for the Advancement of Science and Technology; K.R.H.) and National Institutes of Health R29-HD37360-04 (N.A.K.).
Presented in part at the American Society for Reproductive Medicine 67th annual meeting, Orlando, FL, October 2011.
Financial disclosure/conflicts of interest: None reported.
Address correspondence to: Karl R. Hansen, MD, PhD, Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, PO Box 26901, WP2410, Oklahoma City, OK 73126. E-mail: firstname.lastname@example.org