Repeatability of ovarian antral follicular wave dynamics in women

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.

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.

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.

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.

www.clinicaltrials.gov, identifier NCT01389141.