In ectopic pregnancy deciduas are shed as?

Appeared in: PGIMER Sangrur NO - 2023

Explanation

In an ectopic pregnancy, the uterine lining (endometrium) still undergoes hormonal changes and transforms into a decidua.
The specific layer lining the empty uterine cavity is the decidua vera, also known as the decidua parietalis.
When the ectopic pregnancy fails, hormone levels drop, causing the decidua vera to break down and be shed from the uterus.
This shedding can sometimes occur as a single piece, known as a decidual cast, which can be mistaken for a miscarriage.

Option A: The decidua capsularis is the layer that directly covers the embryo.
Option C: Decidua rubra is an outdated, non-standard term.
Option D: The decidua basalis is the layer that forms the maternal portion of the placenta.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Decidual reaction and shedding in ectopic pregnancy as background academic context rather than a clinical decision trigger.
The shedding of the decidua vera in an ectopic pregnancy can cause vaginal bleeding and may be passed as a 'decidual cast,' which is the entire endometrial lining shed in the shape of the uterine cavity.
Clinically, it is crucial to differentiate a decidual cast from the products of conception of an intrauterine miscarriage. A decidual cast will not contain chorionic villi on histological examination, which is a key diagnostic step when a patient presents with bleeding and tissue passage in early pregnancy.
What if? If a patient with a positive pregnancy test passes tissue that is confirmed histologically to be only decidua (no villi), the suspicion for an ectopic pregnancy becomes very high, and immediate further investigation (e.g., transvaginal ultrasound, serial β-hCG) is warranted to locate the pregnancy and prevent life-threatening rupture.

How to Approach the Question

First, understand the question is asking about the specific part of the uterine lining (decidua) that is shed in an ectopic pregnancy.
Recall the three anatomical parts of the decidua in a normal pregnancy: basalis (at the implantation site), capsularis (covering the embryo), and vera/parietalis (lining the rest of the uterus).
Apply this knowledge to the context of an ectopic pregnancy, where implantation occurs outside the uterus.
Reason that since the embryo is not in the uterus, the decidua basalis and capsularis must be at the ectopic site.
Conclude that the only decidual layer within the uterus that can be shed is the decidua vera (parietalis), which has formed due to hormonal stimulation.
Eliminate the other options based on their definitions and locations.

Concept Tested & Keywords

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E6 Obstetrics Williams pp. 61-84, 19-35

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