**Core Concept**
The corpus luteum of pregnancy is a temporary endocrine structure that forms in the ovary after ovulation and continues to produce progesterone throughout early pregnancy, supporting embryonic implantation and development.

**Why the Correct Answer is Right**
During early pregnancy, the corpus luteum continues to produce progesterone, which is essential for maintaining the endometrium and supporting embryonic development. This process is crucial for the establishment of a successful pregnancy. The corpus luteum also produces human chorionic gonadotropin (hCG), which helps to maintain the corpus luteum and ensure continued progesterone production.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is likely true, as the corpus luteum of pregnancy does indeed produce progesterone. However, without more information, it's difficult to assess its accuracy.

**Option B:** This statement is true, as the corpus luteum of pregnancy produces hCG, which helps to maintain the corpus luteum and ensure continued progesterone production.

**Option C:** This statement is true, as the corpus luteum of pregnancy is indeed a temporary endocrine structure that forms in the ovary after ovulation.

**Option D:** This statement is false, as the corpus luteum of pregnancy continues to produce progesterone throughout early pregnancy, not degenerating early in pregnancy.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the corpus luteum of pregnancy relies on hCG to maintain its function, which is why hCG levels are often used as a marker for early pregnancy and embryonic development.

**Correct Answer:** D.