Oral contraceptives (OCs) are medications taken by mouth to prevent pregnancy.
They typically contain a combination of estrogens and progestins or progestin-only formulations.
Types:
Combined Oral Contraceptives (COCs): Contain both estrogen and progestin (e.g., ethinylestradiol and levonorgestrel).
Progestin-Only Pills (POPs): Contain only progestin (e.g., norethindrone).
Mechanism of Action:
Inhibition of Ovulation: Suppression of the hypothalamic-pituitary-ovarian axis prevents the mid-cycle surge of luteinizing hormone (LH).
Thickening of Cervical Mucus: Impedes sperm penetration.
Endometrial Changes: Make the uterine lining less receptive to implantation.
Clinical Uses of Oral Contraceptives:
Contraception: Preventing unintended pregnancy.
Menstrual Regulation: Treating irregular menstrual cycles, dysmenorrhea.
Acne Management: Particularly with certain progestins.
Polycystic Ovary Syndrome (PCOS): Managing hormonal imbalances.
Endometriosis: Reducing menstrual flow and pain.
Side Effects:
Common: Nausea, weight gain, breast tenderness, mood changes, spotting between periods.
Serious: Increased risk of thromboembolism, stroke, myocardial infarction, especially in smokers and women over 35.
Other: Elevated blood pressure, liver dysfunction, increased risk of certain cancers with long-term use.