Cu ions released from copper-releasing Intra Uterine Devices (IUDs) :-

Options

A. Prevent ovulation
B. Make fallopian tube unsuitable for fertilization
C. Increase phagocytosis of sperms
D. Suppress sperm motility

Answer

### Step-by-Step Solution:

1. **Understanding the Function of Copper IUDs**: Copper-releasing Intrauterine Devices (IUDs) are contraceptive devices that are inserted into the uterus. They release copper ions over time.

2. **Mechanism of Action**: The primary way these copper ions work is by affecting sperm motility. The copper ions released create an environment that is hostile to sperm, which inhibits their movement.

3. **Impact on Fertilization**: By suppressing sperm motility, the copper ions prevent sperm from reaching the site of fertilization, which is the ampulla of the fallopian tube. This means that even if ovulation occurs, the sperm cannot reach the egg to fertilize it.

4. **Duration of Effectiveness**: Copper IUDs are designed to be effective for a long period, typically around 10 to 12 years, with a very low failure rate of about 0.7%.

5. **Evaluating Options**:
- **Option A (Prevents ovulation)**: This is incorrect because copper IUDs do not prevent ovulation; they allow it to occur normally.
- **Option B (Makes fallopian tube unstable for fertilization)**: This is also incorrect as the primary action is on sperm motility, not on the stability of the fallopian tubes.
- **Option C (Increases phagocytosis of sperm)**: This is incorrect as the mechanism does not involve triggering phagocytosis.
- **Option D (Suppress sperm motility)**: This is the correct answer, as the primary function of copper ions is to inhibit sperm movement.

6. **Conclusion**: The correct answer to the question about the action of copper ions released from copper IUDs is that they suppress sperm motility, preventing fertilization.