The corpus luteum is maintained during pregnancy by :-

Options

A. HCG
B. LH
C. Estrogen
D. Progesterone

Answer

### Step-by-Step Solution:

1. **Understanding the Corpus Luteum**: The corpus luteum is a temporary endocrine structure in females that plays a crucial role in the menstrual cycle and early pregnancy. It forms from the ovarian follicle after ovulation and produces hormones, primarily progesterone.

2. **Role of Hormones**: During pregnancy, the maintenance of the corpus luteum is essential for the production of progesterone, which is necessary to maintain the uterine lining and support the early stages of pregnancy.

3. **Evaluating the Options**:
- **Option A: HCG (Human Chorionic Gonadotropin)**: This hormone is produced by the placenta shortly after implantation. It helps maintain the corpus luteum during early pregnancy, ensuring continued progesterone production. Thus, this option is correct.
- **Option B: LH (Luteinizing Hormone)**: This hormone is primarily responsible for triggering ovulation and does not play a role in maintaining the corpus luteum during pregnancy. Therefore, this option is incorrect.
- **Option C: Estrogen**: While estrogen is important for follicle development and has various roles in the menstrual cycle, it does not maintain the corpus luteum during pregnancy. Hence, this option is incorrect.
- **Option D: Progesterone**: Although progesterone is produced by the corpus luteum, it is not the hormone that maintains the corpus luteum itself during pregnancy. Therefore, this option is also incorrect.

4. **Conclusion**: The correct answer is **HCG** (Human Chorionic Gonadotropin), as it is the hormone that maintains the corpus luteum during early pregnancy by stimulating it to continue producing progesterone.

### Final Answer:
The corpus luteum is maintained during pregnancy by **HCG (Human Chorionic Gonadotropin)**.