Repeatability of ovarian antral follicular wave dynamics in women.

Introduction: Two or three waves of follicular development have been documented in the human menstrual cycle; however, the repeatability of ovarian follicular wave dynamics across multiple cycles is not known. In the bovine species, the number of follicular waves has been documented to be repeatable in 2/3 of estrous cycles. We tested the hypotheses that the numbers and patterns of ovarian antral follicular waves in women are repeatable across cycles and become less repeatable with age. Methods: Transvaginal ultrasonography was conducted every 1-3 days over 2 interovulatory intervals (IOIs) for 22 participants. Participants of reproductive age (RA, age 18-35, n=14) and advanced reproductive age (ARA, age 36-55, n=8) were evaluated. The numbers and diameters of follicles ≥2 mm in each ovary were tabulated for each study visit following retrospective review of cineloops. Follicle waves were defined as an increase and subsequent decrease in the number of follicles ≥5 mm, associated with the growth of 2 or more follicles to ≥6 mm. Major waves were defined as a group of follicles from which a dominant follicle was selected for preferential growth. Conversely, in minor waves, selection of a dominant follicle did not occur. The numbers and patterns of follicle waves were compared between cycles and age groups. Results: The mean number of waves was 2.0 in cycle 1 and 2.1 in cycle, with no differences observed between age groups or cycles (p>0.1). Variability in minor and major wave patterns was reported among women, with no difference between age groups or cycles. Overall, 91% of women exhibited repeatability in the number of waves over the 2 IOIs (20/22 women) while 59% exhibited repeatability in wave patterns (13/22 women). Repeatability in the numbers and patterns of waves did not differ between age groups. Discussion: Data suggest that the numbers and patterns of antral follicular waves are repeatable across 2 cycles in the majority of women. Research is ongoing to further characterize antral follicular wave dynamics, which may enable personalization of ovarian stimulation therapies. Clinical trial registration: www.clinicaltrials.gov, identifier NCT01389141.