The cardinal function of decidua is?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Obstetrics & Gynaecology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Explanation

The cardinal, or primary, function of the decidua is the maintenance of pregnancy.
The decidua is the specialized, modified endometrium (lining of the uterus) that forms during pregnancy to create a supportive environment for the embryo.
It provides a receptive site for implantation, nourishes the early embryo, and regulates the maternal immune response to prevent fetal rejection.
Other functions, such as hormone production (e.g., prolactin) and immune modulation, are specific mechanisms that serve the main purpose of maintaining the pregnancy.

Option A: While the decidua plays a vital role in creating an immunologically privileged site to prevent the mother's immune system from rejecting the fetus, this is a specific mechanism, not the overarching primary function.
Option B: The decidua does produce hormones like prolactin and relaxin, but this is one of its several functions that contribute to the larger goal of maintaining the pregnancy, rather than being the cardinal function itself.
Option D: The term "cardinal" implies a single, most important function. While the decidua performs all the listed roles (immunity, hormone production), they are all in service of the primary objective, which is the maintenance of pregnancy. Therefore, this option is less precise.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Primary function of the decidua during pregnancy as background academic context rather than a clinical decision trigger.
A defective decidual response (decidualization) is a significant cause of pregnancy complications, including implantation failure, recurrent pregnancy loss, and pre-eclampsia.
Understanding the decidua's functions is crucial for managing high-risk pregnancies and investigating causes of infertility.
What if? If the decidua failed to properly regulate the invasion of placental trophoblast cells, it could lead to placenta accreta spectrum disorders, where the placenta attaches too deeply into the uterine wall. This can cause life-threatening hemorrhage at the time of delivery.

How to Approach the Question

First, identify the key term in the question: "cardinal function." This means the most important or primary function.
Analyze the options provided: Immunity, Production of hormones, and Maintenance of pregnancy.
Consider the relationship between these options. Ask yourself: Do the immunological and hormonal functions of the decidua serve a larger purpose?
Recognize that both immune modulation and hormone secretion are mechanisms by which the decidua helps to maintain the pregnancy.
Therefore, "Maintenance of pregnancy" is the most comprehensive and primary (cardinal) function, as it encompasses the other roles.
This reasoning eliminates options A and B as being too specific and option D because the question asks for the single most important function, not all of them.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 61-84