Objective: Changes in antral follicle count, hormone production, and menstrual cyclicity as women age are well documented. However, age-related changes in ovarian follicular wave dynamics in women are not understood. The objective of this study was to test the hypothesis that major follicular wave dynamics (ie, those in which a dominant follicle develops) differ in women with age.
Methods: A prospective, cross-sectional, observational study was conducted in 58 women of mid-reproductive age (MRA; 18-35 y; n = 27), late reproductive age (LRA; 36-44 y; n = 10), and advanced reproductive age (ARA; 45-55 y; n = 21). The number and diameters of all follicles ≥ 2 mm were quantified ultrasonographically every 2 to 3 days for one complete interovulatory interval (IOI). Only ovulatory cycles were evaluated. Antral follicle count and major follicular wave dynamics during the IOI were compared among age groups using SPSS version 19.0 (α = 0.05).
Results: One (36/58, 62%) or two (22/58, 38%) major follicular waves were observed during the IOI in all women evaluated. The prevalence of follicular-phase dominant follicles (FPDFs) and luteal-phase dominant follicles (LPDFs) was not different among the MRA, LRA, and ARA groups (FPDFs: 27/27 [100%], 10/10 [100%], and 20/21 [95%], respectively; LPDFs: 10/17 [37%], 3/10 [30%], and 10/21 [48%], respectively; P > 0.050). All FPDFs were ovulatory. One LPDF ovulated during menses in the ARA group; all other LPDFs in the MRA, LRA, and ARA groups were anovulatory. On average, LPDFs emerged earlier relative to ovulation (days −6, −2, and −2; P = 0.049), grew longer (11, 3, and 6 d; P = 0.005), and developed to a larger diameter (24, 11, and 11 mm; P = 0.032) in the ARA group versus the MRA and LRA groups. In follicular-phase major waves, there was a tendency for a greater prevalence of polyovulation as women aged (ARA 3/21 [14%] vs MRA 0/27 [0%]; P = 0.070).
Conclusions: One or two major follicular waves develop during the IOI, irrespective of age. The prevalence of LPDFs (range, 30%-50%) and FPDFs (range, 95%-100%) during the IOI does not differ with age. However, the growth dynamics of major waves change as women age. On average, LPDFs emerge earlier, grow for a longer period, and grow to a larger diameter in ovulatory women of advanced versus mid or late reproductive age. There is a greater tendency for polyovulation in the follicular-phase major wave as women age.
From the 1Department of Obstetrics, Gynecology, and Reproductive Sciences, College of Medicine, University of Saskatchewan, Saskatchewan, Canada; and 2Department of Obstetrics and Gynecology, University of Sydney, New South Wales, Australia.
Received November 9, 2012; revised and accepted February 12, 2013.
Funding/support: This work was supported by the Canadian Institutes of Health Research, Canadian Foundation for Women’s Health, and University of Saskatchewan.
Financial disclosure/conflicts of interest: None reported.
Address correspondence to: Angela Baerwald, PhD, Department of Obstetrics, Gynecology, and Reproductive Sciences, College of Medicine, University of Saskatchewan, Royal University Hospital, 103 Hospital Drive, Saskatoon, Saskatchewan, Canada S7N 0W8. E-mail: email@example.com