Question

birth control pills are a popular form of contraception for women. how do birth control pills prevent pregnancy?

by covering the cervix and blocking sperm from entering the uterus
by blocking the fallopian tubes and keeping the eggs from reaching the uterus
by introducing female hormones that prevent the ovaries from releasing eggs

Explanation:

Identify the question and options

The question asks how birth control pills prevent pregnancy. The options describe different mechanisms of contraception:

1. Covering the cervix and blocking sperm (barrier method, e.g., diaphragm or cervical cap).
2. Blocking the fallopian tubes (surgical method, e.g., tubal ligation).
3. Introducing female hormones that prevent the ovaries from releasing eggs (hormonal method).

Analyze the mechanism of birth control pills

Using the Contraceptives knowledge point, we know that oral contraceptive pills are a form of hormonal contraception. They contain synthetic versions of the female hormones estrogen and progestin (or progestin only). These hormones signal the brain to suppress the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which prevents ovulation (the release of an egg from the ovaries). Without an egg, fertilization cannot occur.

Evaluate the options

• Option 1 describes a physical barrier method.
• Option 2 describes a surgical or physical blockage.
• Option 3 correctly describes the hormonal mechanism of preventing ovulation.

Answer:

• by covering the cervix and blocking sperm from entering the uterus
• by blocking the fallopian tubes and keeping the eggs from reaching the uterus
• by introducing female hormones that prevent the ovaries from releasing eggs (Correct answer)