In ectopic pregnancy decidua's are shed as?

AIIMS Delhi NO - 2017

Obstetrics & Gynaecology

Medium

Appeared in: AIIMS Delhi NO - 2017

Explanation

In an ectopic pregnancy, the uterus still undergoes a decidual reaction due to hormonal stimulation, even though the embryo is implanted elsewhere.
The decidua vera (also called decidua parietalis) is the specific layer that lines the main uterine cavity, separate from the site of implantation.
When the ectopic pregnancy is non-viable and hormonal support wanes, the decidua vera loses its support, breaks down, and is shed, resulting in vaginal bleeding.
This shedding can sometimes occur as a single piece of tissue shaped like the uterine cavity, known as a decidual cast.

Option A: The decidua capsularis is the layer that overlies the embryo. In an ectopic pregnancy, it is located at the ectopic site (e.g., fallopian tube) along with the embryo, not within the uterine cavity.
Option B: Decidua rubra is not a standard, current anatomical term for any part of the decidua. The correct terminology is decidua basalis, capsularis, and vera (parietalis).
Option D: The decidua basalis forms at the site of implantation and develops into the maternal portion of the placenta. In an ectopic pregnancy, this layer is located at the ectopic site, not in the uterus.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of decidual shedding in ectopic pregnancy as background academic context rather than a clinical decision trigger.
The shedding of a decidual cast can be mistaken for a miscarriage of an intrauterine pregnancy. It is crucial for nurses to instruct patients to save any passed tissue for pathological examination to differentiate the two conditions.
The classic triad of symptoms for ectopic pregnancy is amenorrhea (missed period), abdominal pain, and vaginal bleeding. The shedding of the decidua vera contributes to this bleeding.
Recognizing the possibility of an ectopic pregnancy is critical because a ruptured ectopic pregnancy is a life-threatening medical emergency causing severe internal hemorrhage.

How to Approach the Question

First, identify the key concepts in the question: 'ectopic pregnancy' and 'decidua'.
Recall the three distinct layers of the decidua formed during pregnancy: basalis, capsularis, and vera (parietalis).
Visualize the location of each layer in a normal intrauterine pregnancy: basalis is under the embryo, capsularis is over the embryo, and vera lines the rest of the uterus.
Now, apply this to the abnormal situation of an ectopic pregnancy, where the embryo is outside the uterus.
Deduce that the decidua basalis and capsularis must be located at the ectopic site with the embryo (e.g., in the fallopian tube).
Therefore, the only decidual layer that lines the now-empty uterine cavity and can be shed through the vagina is the decidua vera.

Concept Tested & Keywords

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E6 Obstetrics Williams pp. 61-84, 19-34