High level of hCG is/are seen in all except :
**Core Concept**
High levels of human chorionic gonadotropin (hCG) are typically associated with pregnancy, specifically during the first trimester. hCG is a hormone produced by the placenta, and its levels increase rapidly during early pregnancy.
**Why the Correct Answer is Right**
The primary function of hCG is to maintain the corpus luteum, ensuring continued production of progesterone, which is essential for early fetal development. hCG has a structure similar to luteinizing hormone (LH), allowing it to bind to the LH receptor and stimulate the corpus luteum. This is why hCG levels are used as a marker for pregnancy and fetal well-being.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as high levels of hCG are a hallmark of pregnancy.
**Option B:** Incorrect, as hCG is commonly used in pregnancy tests to detect the presence of this hormone.
**Option C:** Incorrect, as ectopic pregnancies, although less common, can still produce high levels of hCG, albeit often with abnormal values due to the location of the embryo outside the uterus.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that an isolated high hCG level can be seen in conditions like gestational trophoblastic disease (GTD), which includes molar pregnancies and gestational trophoblastic neoplasia (GTN). These conditions require prompt diagnosis and management to prevent complications.
**Correct Answer: D. Choriocarcinoma**