Image analysis of dominant ovarian follicles and ovarian follicular development during continuous and conventional oral contraceptive dosing schemes

The objective of this research was to assess ultrasound image attributes of human dominant ovarian follicles in the final stages of development during natural and oral contraceptive (OC) cycles, as well as characterize ovarian follicular and endometrial development during and after continuous versus conventional dosing schemes. We utilized sophisticated computer algorithms to elucidate an association between image attributes and physiologic status of follicles in their final stage of development. We used transvaginal ultrasonography to quantify changes in the numbers and diameters of ovarian follicles and changes in endometrial thickness and pattern during and following discontinuation of two different regimens of OC. Developmental changes in ovarian follicles and corpora lutea were correlated with serum estradiol-17â and progesterone, respectively to provide a comprehensive approach to examining ovarian and uterine function. We reported for the first time that follicles which develop during natural and OC cycles have similar image attributes, which provides preliminary evidence that image attributes of human follicles are associated with physiologic status during the growth phase. Further research should be performed to elucidate the exact correlation between image attributes during all stages of follicular development throughout the menstrual cycle, prediction of dysfunctional follicular development (i.e., hemorrhagic anovulatory follicles) and the effects of different OC formulations on follicle development. Once the association between image attributes and various scenarios of follicular development are determined, a computer program could be developed to assess follicular health with a single ultrasound examination, obviating many ethical constraints that currently prevent large scale progress in ovarian follicular research. We further documented that continuous OC administration schemes provide greater follicular suppression than conventional dosing schemes. No dominant follicles developed during three consecutive 28 day cycles of continuous OC use, whereas eight dominant follicles developed during the same time period of conventional OC use. We interpreted these findings to mean that continuous OC dosing schemes provide a more effective contraceptive with a decreased risk of “escape” ovulation compared to conventional dosing schemes. Most follicles ovulated in the immediate cycle following discontinuation of OC. We suggest that the delay to fertility following cessation of OC is not due to anovulation but other yet, unknown, biological factors