Human Ovarian Follicular Dynamics and Emergency Contraception

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 estradiol/0.5 mg levonorgestrel pills at different stages of the menstrual follicular cycle.

Inclusion criteria

• Female volunteers of childbearing potential;
• Are first time users of oral contraception (OC) or have discontinued OC at least 1 month prior to study entry;
• Age between 18 and 40 years old;
• Normal body mass index (18-38);
• Has signed informed consent form; and
• Is in good health as confirmed by medical history, physical examination.

Exclusion criteria

• A positive pregnancy test will automatically exclude the volunteer from participation in this study.
• Any contraindication for oral contraception use;
• Irregular menstrual cycles;
• Ultrasonographic evidence of ovarian dysfunction, such as polycystic ovary syndrome (PCOS);
• Pregnancy (suspected or diagnosed) or lactation;
• History or suspicion of drug or alcohol abuse;
• Participation in an investigational drug trial within the 30 days prior to selection;
• Exhibits a disorder that is a contraindication to steroid hormonal therapy, including, for example, the following conditions:

• history of, or actual, thrombophlebitis or thromboembolic disorders.
• history of, or actual, cerebrovascular disorders.
• history of, or actual, myocardial infarction or coronary artery disease.
• acute liver disease.
• history of, or actual, benign or malignant liver tumors.
• history of, or suspected, carcinoma of the breast.
• known, or suspected, estrogen-dependent neoplasia.
• undiagnosed abnormal vaginal bleeding.
• any ocular lesion arising from ophthalmic vascular disease, such as partial or complete loss of vision or defect in visual field.