Medicine & USMLE

Oral Contraceptive Pills

Maternity Drugs
  1. Methyldopa
  2. Oral Contraceptive Pills


Oral contraceptive pills, or OCPs for short, contain a combination of the hormones estrogen and progesterone. As contraceptives, these drugs are used to prevent pregnancy, however they carry a risk of causing blood clots. For this reason, OCPs are not recommended in patients with a prior history of blood clots, those who smoke, or patients who have hypertension.

Key Points

  • Oral Contraceptive Pills (OCPs)
    • Key Drugs
      • Estrogen
        • Most common synthetic estrogen used is ethinyl estradiol (EE)
      • Progesterone
        • Many different types of progestin: norethindrone, ethynodiol diacetate, norgestrel, levonorgestrel, desogestrel, norgestimate, etc.
      • OCPs can include a combination of estrogen and progesterone, or some are progesterone-only
    • Mechanism
      • Estrogen
        • Inhibits ovulation by preventing formation of a dominant follicle
      • Progesterone
        • Suppresses the luteinizing hormone (LH) surge that is required for ovulation
        • Alters the uterine lining so it's not as favorable for implantation
        • Thickens cervical mucus
    • Clinical Use
      • Contraception
        • One pill taken daily
        • 21 days of active pills, followed by 7 days of inert pills during which the user may experience withdrawal bleeding. Some manufacturers will include iron supplementation in the inert pills to prevent iron-deficiency anemia.
        • Backup contraception should be used for the first 7 days after starting OCPs
      • Menstrual Irregularity
        • OCPs can be used to alter hormone balance to correct for irregular menses
    • Side Effects and Adverse Reactions
      • Increased risk for blood clots
        • Not recommended for people with a history of clots
          • Deep vein thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI), or cardiovascular accident (CVA) stroke
        • Not recommended for those who smoke or have hypertension
          • At a higher risk for blood clots
          • Do not smoke while taking oral contraceptives
          • Report severe leg pain and swelling (DVT), loss of vision or headaches (stroke), or chest pain (PE or MI)
      • Contraindicated with history of estrogen-dependent tumors
        • E.g. certain types of breast cancer, endometrial cancer, ovarian cancer
      • Breast tenderness
        • Normal, expected side effect. No need to report.
      • Spotting between menses
        • Normal, expected side effect. No need to report.
      • Increased risk for cervical cancer
      • Does NOT protect against sexually transmitted infections (STIs)