Mechanism of action of oral contraceptive pills is :-

Options

A. Prevents ovulation
B. Increases cervical mucous thickening
C. Acts as a spermicidal agent
D. Increases basal body temperature

Answer

**Step-by-Step Solution:**

1. **Understanding Oral Contraceptive Pills (OCPs):**
- Oral contraceptive pills are medications taken by women to prevent pregnancy. They typically contain hormones, primarily estrogen and progesterone.

2. **Hormonal Composition:**
- OCPs usually consist of a combination of two hormones:
- **Estrogen**: A female hormone that regulates the menstrual cycle.
- **Progesterone**: Often referred to as the pregnancy hormone, it plays a crucial role in maintaining pregnancy.

3. **Primary Mechanism of Action:**
- The main mechanism by which OCPs prevent pregnancy is by **inhibiting ovulation**. This means that the pills prevent the ovaries from releasing an egg, which is essential for fertilization.

4. **Additional Mechanisms:**
- Besides preventing ovulation, OCPs also:
- **Increase the thickness of cervical mucus**: This makes it more difficult for sperm to enter the uterus.
- **Alter the endometrial lining**: This makes it less suitable for implantation of a fertilized egg.
- **May increase basal body temperature**: This can also contribute to preventing ovulation.

5. **Conclusion:**
- The primary action of oral contraceptive pills is to prevent ovulation, which is the key factor in preventing pregnancy.

**Final Answer:**
- The mechanism of action of oral contraceptive pills is to **prevent ovulation**.

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