Ovarian follicular dynamics during conventional vs. continuous oral contraceptive use.

OBJECTIVES: The purpose of this study was to characterize ovarian follicular and endometrial development during conventional vs. continuous oral contraceptive (OC) dosing regimens, to explore follicular development during the hormone-free interval (HFI) and to examine follicular development following OC discontinuation. STUDY METHODS: A randomized clinical trial involving 36 clinically normal healthy women between the ages of 18 and 35 years (24.4 +/- 3.9, SEM). Transvaginal ultrasonography and blood sampling were done to ascertain ovarian function. RESULTS: Fewer follicles > 4 mm developed during continuous vs. conventional OC use (p = .006). No dominant follicles developed during continuous OC use vs. eight dominant follicles (16.1 +/- 3.3 mm) during the conventional OC regimen. Two of eight (25%) dominant follicles ovulated. All dominant follicles began development during the HFI. Following discontinuation of OC use, ovulation took approximately 5 days longer when compared to natural cycles. CONCLUSION: Continuous OC regimens more effectively prevent dominant follicle development and breakthrough ovulation. The slight delay in time to ovulation following OC discontinuation and natural cycles could be attributed to suppression of follicle wave activity.

Ultrasound image attributes of human ovarian dominant follicles during natural and oral contraceptive cycles.

BACKGROUND: Computer-assisted analyses were used to examine ultrasound image attributes of human dominant ovarian follicles that developed during natural and oral contraceptive (OC) cycles. We hypothesized that image attributes of natural cycle follicles would quantitatively differ from those in OC cycles and that OC cycle follicles would possess image attributes indicative of atresia. METHODS: Dominant ovarian follicles of 18 clinically normal women were compared using transvaginal ultrasonography for the 7 days before ovulation during a natural cycle (n = 9) or the 7 days before peak estradiol in women using OC (n = 11). Follicles were analyzed using region and line techniques designed to compare the image attributes numerical pixel value (NPV), pixel heterogeneity (PH) and area under the curve (AUC). RESULTS: NPV was higher in OC cycle follicles with region analysis and tended to be higher with line analysis (p = 0.005 and p = 0.06, respectively). No differences were observed in two other image attributes (AUC and PH), measured with either technique, between natural and OC cycle follicles. CONCLUSION: The increased NPV value of OC cycle follicles and lack of differences in PH and AUC values between natural cycle and OC cycle follicles did not support the hypothesis that OC cycle follicles would show ultrasonographically detectable signs of atresia. Image attributes observed in OC cycle follicles were not clearly indicative of atresia nor were they large enough to preclude preovulatory physiologic status in OC cycle follicles.