Oral Contraceptive Hormone-free Interval Pituitary/ Ovarian Activity

The degree of suppression and subsequent activation of the hypothalamic-pituitary-ovarian axis during the hormone-free interval in combined oral contraceptive (COC) hormone users varies depending on the dose of ethinyl estradiol in the formulation. This variation in activation may be associated with different side effects during the hormone free interval. Progesterone (P) remained suppressed during all 6 COC regimens (\<1.8 ng/mL), which indicates continuous contraceptive efficacy during the 7-day hormone free interval of all formulations studied.