<qa>  What is the Yuzpe regimen?This study is a single-center, randomized, open-label, double-controlled protocol to study the pattern of ovarian follicular growth and regression in two groups of women. The first group will use Plan B, which is a progesterone only OC containing 0.75 levonorgestrel. The second group of women will use the Yuzpe regimen, which uses 50 mg ethinyl estradiol0.5 mg levonorgestrel pills at different stages of the menstrual follicular cycle. 