Pregnancy is characterised by all, except

Options

A. Human placental lactogenic hormone keeps increasing throughout pregnancy
B. Pulsatile GnRH stimulates the anterior lobe to secrete FSH and LH
C. Corpus luteum is rescued from regression by hCG, produced by syncytiotrophoblast or chorion in the first trimester
D. In first trimester corpus luteum, stimulated by hCG is responsible for the production of estrogen and progesterone

Answer

To solve the question "Pregnancy is characterised by all, except," we need to analyze the provided options and identify which statement is not true regarding pregnancy.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a statement that does not characterize pregnancy. This means we need to find the option that is incorrect or not applicable during pregnancy.

2. **Evaluate Each Option**:
- **Option 1**: "Human placental lactogenic hormone keeps increasing throughout pregnancy."
- This statement is true. Human placental lactogenic hormone (HPL) is indeed produced by the placenta and its levels increase during pregnancy to support metabolism.

- **Option 2**: "Pulsatile GnRH stimulates the anterior lobe to secrete FSH and LH."
- This statement is generally true; however, during pregnancy, the focus shifts away from the normal menstrual cycle and ovulation does not occur. Therefore, while GnRH does stimulate FSH and LH, this process is not relevant during pregnancy.

- **Option 3**: "Corpus luteum is rescued from regression by hCG produced by syncytiotrophoblast and chorion in the first trimester."
- This statement is true. Human chorionic gonadotropin (hCG) is produced by the placenta and helps maintain the corpus luteum, which is crucial for progesterone production during early pregnancy.

- **Option 4**: "In the first trimester, corpus luteum stimulated by hCG is responsible for the production of estrogen and progesterone."
- This statement is also true. The corpus luteum produces both estrogen and progesterone, which are essential for maintaining pregnancy in the first trimester.

3. **Identify the Incorrect Statement**: After evaluating all options, we find that Option 2 is the only statement that does not accurately characterize pregnancy since the secretion of FSH and LH is not relevant during this time.

### Final Answer:
The correct answer is **Option 2**.

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