Cu ions released from copper releasing intrauterine devices (IUDs)

Options

A. prevent ovulation
B. make uterus unsuitable for implantation
C. decrease phagocytosis of sperms
D. suppress sperm motility

Answer

**Step-by-Step Solution:**

1. **Understanding Intrauterine Devices (IUDs)**:
- IUDs are contraceptive devices that are inserted into the uterus to prevent pregnancy. They can be classified into hormone-releasing and non-hormone (or copper-releasing) types.

2. **Focus on Copper-Releasing IUDs**:
- The question specifically addresses copper-releasing IUDs. These devices release copper ions into the uterine environment.

3. **Mechanism of Action**:
- The primary function of copper ions released from these IUDs is to create an environment that is hostile to sperm. This includes decreasing sperm motility, which is crucial for fertilization.

4. **Evaluating the Options**:
- **Option A: Prevent ovulation** - Copper IUDs do not primarily prevent ovulation.
- **Option B: Make uterus unsuitable for implantation** - While they do create an unfavorable environment, the main action is related to sperm.
- **Option C: Decrease phagocytosis of sperms** - This is incorrect; the IUDs actually increase the phagocytosis of sperm.
- **Option D: Suppress sperm motility** - This is the correct answer, as copper ions inhibit sperm motility, preventing fertilization.

5. **Conclusion**:
- The correct answer is **Option D: Suppress sperm motility**. This is the primary action of copper ions released from copper-releasing IUDs, leading to effective birth control.

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