What is the primary hormone contained in the oral contraceptive known as the "mini-pill"?

• A. Estrogen only
• B. Progesterone only
• C. Equal parts estrogen and progesterone
• D. A higher dose of progesterone than estrogen

Answer: (B)

The primary hormone contained in the oral contraceptive known as the "mini-pill" is progesterone only. The "mini-pill" is specifically designed to prevent ovulation and alter the menstrual cycle with the sole use of progestin, which is a synthetic form of progesterone. By using only progesterone, the mini-pill can effectively thicken cervical mucus to prevent sperm from entering the uterus and also thin the endometrial lining, making it less suitable for implantation, should fertilization occur.

This formulation is particularly beneficial for individuals who may experience side effects from estrogen or who are breastfeeding, as it poses fewer risks related to estrogen-related complications. Other contraceptive options that include estrogen generally work by inhibiting ovulation through a combination of both hormones, but the "mini-pill" relies solely on progesterone, highlighting its specific role in contraceptive methods focusing on progestin-only mechanisms.