Source of H.C.G. is

Appeared in: UPPSC 2017

Explanation

Human Chorionic Gonadotropin (hCG) is a peptide hormone produced by the placenta during pregnancy.
The primary site of hCG production is the syncytiotrophoblast, which is the outer layer of the trophoblast cells forming the placenta.
hCG is crucial for maintaining the corpus luteum in early pregnancy, ensuring continued progesterone secretion until the placenta can produce its own.
hCG levels rise rapidly in early pregnancy, doubling approximately every two days, and peak during the first trimester.

Option B: The cytotrophoblast is the inner layer of the trophoblast and serves as a precursor to the syncytiotrophoblast. It is not the primary site of hCG production, although it may secrete a variant in very early pregnancy.
Option C: The amnion is the innermost fetal membrane that forms the amniotic sac and contains amniotic fluid. It has a protective function and is not involved in hormone synthesis.
Option D: The chorion is the outermost fetal membrane, which includes the trophoblast. While this is technically correct in a broader sense, 'Syncytiotrophoblast' is the more specific and precise answer as it names the exact cell type responsible for hCG production.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Source of Human Chorionic Gonadotropin (hCG) as background academic context rather than a clinical decision trigger.
Measuring hCG levels is the basis for most pregnancy tests (both urine and blood).
Serial monitoring of hCG levels is critical in early pregnancy to assess viability. Abnormally low or slowly rising levels can indicate an ectopic pregnancy or a potential miscarriage.
Extremely high hCG levels can be a sign of a molar pregnancy (gestational trophoblastic disease) or a multiple gestation (e.g., twins).

How to Approach the Question

First, identify the core of the question: it's asking for the specific biological source of the hormone hCG.
Recall the structures involved in early pregnancy and placentation: amnion, chorion, cytotrophoblast, and syncytiotrophoblast.
Differentiate the functions of these structures. The amnion is the inner sac. The chorion is the outer membrane that forms the placenta.
Focus on the layers of the chorion's trophoblast: the inner cytotrophoblast (proliferative layer) and the outer syncytiotrophoblast (functional, hormone-secreting layer).
Recognize that the syncytiotrophoblast is the specialized layer that directly interacts with maternal blood and is responsible for secreting hormones like hCG.
Select the most specific and accurate option. While the chorion contains the syncytiotrophoblast, 'Syncytiotrophoblast' itself is the precise answer.

Concept Tested & Keywords

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E6 Gynecology Williams pp. 351-421, 352-421, 350-421

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Attempt every question from this paper in a timed mock, then review the full solution for each one.