Which hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy ?

Options

A. LH
B. FSH
C. hCG
D. GnRH

Answer

To answer the question "Which hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Corpus Luteum**:
- After ovulation, the remaining follicle transforms into the corpus luteum, which is a temporary endocrine structure.
- The corpus luteum is responsible for producing hormones, primarily progesterone and estrogen.

2. **Role of Hormones in Pregnancy**:
- During the first trimester of pregnancy, it is crucial for the corpus luteum to continue secreting progesterone and estrogen to maintain the pregnancy.
- These hormones help in preparing the uterine lining for implantation and maintaining it for the developing embryo.

3. **Identifying the Hormone Responsible**:
- The question asks which hormone is responsible for maintaining the secretion of progesterone and estrogen from the corpus luteum during the first trimester.
- The options provided include LH (Luteinizing Hormone), FSH (Follicle Stimulating Hormone), HCG (Human Chorionic Gonadotropin), and GnRH (Gonadotropin-Releasing Hormone).

4. **Evaluating Each Option**:
- **LH**: Primarily responsible for triggering ovulation and the formation of the corpus luteum but does not maintain its function during pregnancy.
- **FSH**: Responsible for the growth of ovarian follicles, not directly involved in maintaining the corpus luteum during pregnancy.
- **HCG**: Human Chorionic Gonadotropin is produced by the developing embryo and is crucial for maintaining the corpus luteum. It signals the corpus luteum to continue producing progesterone and estrogen during the first trimester.
- **GnRH**: Released from the hypothalamus and stimulates the pituitary gland to release LH and FSH but does not directly maintain the corpus luteum.

5. **Conclusion**:
- The correct answer is **HCG (Human Chorionic Gonadotropin)**, as it is the hormone that maintains the secretion of progesterone and estrogen by the corpus luteum during the first trimester of pregnancy.

### Final Answer:
**HCG (Human Chorionic Gonadotropin)**