Ovulation does not occur during pregnancy in the human female because

Options

A. The follicles are not influenced by the level of progesterone in the blood
B. The corpus luteum and later the placenta produces large amounts of progesterone
C. The corpus luteum degenerates as lutenising hormone is no longer produced
D. The embryo produces hormones which retard the production of maternal follicle simulating hormones

Answer

**Step-by-Step Solution:**

1. **Understanding Ovulation**: Ovulation is the process where an ovary releases an egg, typically occurring around the 14th day of the menstrual cycle. This process is regulated by hormones, particularly the luteinizing hormone (LH).

2. **Role of Luteinizing Hormone (LH)**: LH is responsible for triggering ovulation. During a normal menstrual cycle, there is a surge in LH levels that leads to the release of an egg from the ovary.

3. **Hormonal Changes During Pregnancy**: When a woman becomes pregnant, the hormonal environment changes significantly. The levels of LH drop to almost nil, while the levels of progesterone increase significantly. Progesterone is crucial for maintaining the pregnancy.

4. **Impact of High Progesterone Levels**: High levels of progesterone during pregnancy inhibit the ovarian follicles from maturing and releasing eggs. This is because progesterone prevents the secretion of follicle-stimulating hormone (FSH) and LH, which are necessary for ovulation.

5. **Role of Corpus Luteum and Placenta**: The corpus luteum, which forms after ovulation, produces progesterone. However, during pregnancy, the placenta takes over this role and produces even larger amounts of progesterone, further suppressing ovulation.

6. **Conclusion**: Therefore, ovulation does not occur during pregnancy primarily because the corpus luteum degenerates due to the lack of LH, and the high levels of progesterone prevent the maturation of ovarian follicles.

**Final Answer**: Ovulation does not occur during pregnancy in the human female because the corpus luteum degenerates as luteinizing hormone is no longer produced.

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