The immediate cause of menstruation is the withdrawal of

Options

A. LH
B. FSH
C. estrogen
D. progesterone

Answer

### Step-by-Step Solution:

1. **Understanding Menstruation**: Menstruation is a monthly process in the female reproductive system where the lining of the uterus (endometrium) is shed if pregnancy does not occur.

2. **Role of Hormones**: The menstrual cycle is regulated by various hormones, primarily Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), and Progesterone.

3. **Ovulation and Corpus Luteum Formation**: After ovulation, the remaining follicle transforms into the corpus luteum, which produces progesterone. This hormone is crucial for maintaining the endometrial lining.

4. **Effects of Progesterone**: Progesterone helps to thicken the endometrium and suppresses the production of FSH and LH. This suppression prevents the maturation of new follicles during the luteal phase.

5. **Withdrawal of Hormones**: If fertilization does not occur, the corpus luteum degenerates, leading to a decrease in progesterone levels. The drop in progesterone is the immediate trigger for menstruation.

6. **Conclusion**: The immediate cause of menstruation is the withdrawal of progesterone due to the degeneration of the corpus luteum.

### Final Answer:
The immediate cause of menstruation is the withdrawal of **progesterone**.

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