If there is no fertilization then corpus luteum starts degeneration on 9th day of its formation. Reason of start of degeneration is :-

Options

A. Increase in amount of LH
B. Decrease in amount of LH
C. Increase in amount of GnRH
D. Decrease in level of progesteron

Answer

To solve the question regarding the degeneration of the corpus luteum when there is no fertilization, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Corpus Luteum Formation**:
- After ovulation, the ruptured follicle transforms into the corpus luteum, which is responsible for producing hormones, primarily progesterone.

2. **Role of Hormones**:
- The corpus luteum is maintained by luteinizing hormone (LH) produced by the anterior pituitary gland. LH is crucial for the survival of the corpus luteum.

3. **Fertilization Status**:
- If fertilization occurs, the developing embryo produces human chorionic gonadotropin (hCG), which maintains the corpus luteum and prevents its degeneration.
- If fertilization does not occur, there is no hCG production.

4. **Degeneration Timeline**:
- In the absence of fertilization, the corpus luteum starts to degenerate approximately 9 days after ovulation.

5. **Hormonal Changes**:
- The key reason for the degeneration of the corpus luteum is the decrease in LH levels. Without LH, the corpus luteum cannot be sustained, leading to its degeneration.

6. **Conclusion**:
- Therefore, the primary reason for the degeneration of the corpus luteum when there is no fertilization is the decrease in the amount of LH.

### Final Answer:
The reason for the start of degeneration of the corpus luteum when there is no fertilization is the **decrease in the amount of LH**.

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