There is no menstruatin during pregnancy . This is due to high levels of ______

Options

A. Estrogen
B. Progesterone
C. Gonadotropins
D. GnRH

Answer

**Step-by-Step Solution:**

1. **Understanding Menstruation and Pregnancy:**
- Menstruation is the monthly shedding of the uterine lining when fertilization does not occur. During pregnancy, this process is halted.

2. **Role of Hormones:**
- The menstrual cycle is regulated by various hormones, including estrogen and progesterone.
- When fertilization occurs, the hormonal balance changes significantly.

3. **High Levels of Progesterone:**
- During pregnancy, the corpus luteum (a temporary endocrine structure) produces high levels of progesterone.
- Progesterone is crucial for maintaining the endometrial lining of the uterus, which is necessary for the implantation of the fertilized egg.

4. **Consequences of Low Progesterone:**
- If fertilization does not occur, the corpus luteum degenerates, leading to a drop in progesterone levels, which triggers menstruation.

5. **Conclusion:**
- Therefore, the absence of menstruation during pregnancy is due to the high levels of progesterone.

**Final Answer:**
There is no menstruation during pregnancy. This is due to high levels of **progesterone**.

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