An occurrence in which umbilical cord vessels pass through the placental membranes and lie across the cervica… - AIIMS Raipur NO - 2019 (Shift-1)

AIIMS Raipur NO - 2019 (Shift-1)

Obstetrics & Gynaecology

Easy

Appeared in: AIIMS Raipur NO - 2019 (Shift-1)

Explanation

Vasa previa is an obstetric complication where fetal blood vessels, unsupported by Wharton's jelly or placental tissue, run through the amniotic membranes and lie across or in close proximity to the internal cervical os.
This positioning makes the vessels vulnerable to rupture when the membranes break or during labor, which can lead to rapid fetal exsanguination and death.
The condition is classified as type 1 when the vessels are part of a velamentous cord insertion, and type 2 when they connect a bilobate or succenturiate placenta.
Antenatal diagnosis via transvaginal ultrasound with color Doppler is critical, as it allows for a planned cesarean delivery, which significantly improves perinatal survival rates to nearly 100%.

Option A: Abruptio placentae is the premature separation of a normally implanted placenta from the uterine wall. It does not involve the location of the umbilical cord vessels relative to the cervix.
Option B: Placenta previa is the implantation of the placenta itself over or near the cervical os. In this condition, the fetal vessels are protected within the placental tissue, unlike in vasa previa where they are exposed.
Option C: Placenta accreta describes an abnormal, deep attachment of the placenta into the myometrium (the muscular wall of the uterus). It is a condition of placental adherence, not vessel location.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Placental and Umbilical Cord Abnormalities as background academic context rather than a clinical decision trigger.
The primary clinical significance of vasa previa is the extremely high risk of fetal mortality if it is not diagnosed before labor. Rupture of these vessels can lead to fetal death within minutes.
Nursing assessment for any vaginal bleeding during pregnancy must consider vasa previa as a differential diagnosis, especially if the bleeding occurs with rupture of membranes and is accompanied by acute fetal distress (e.g., bradycardia).
Management of diagnosed vasa previa involves close surveillance, administration of antenatal corticosteroids to promote fetal lung maturity, and a planned cesarean delivery between 34 to 36 weeks of gestation to avoid the onset of labor and membrane rupture.

How to Approach the Question

First, break down the question stem to identify the key defining features: 1) umbilical cord vessels, 2) passing through placental membranes, and 3) lying across the cervical os.
This description points to a specific anatomical abnormality where the fetal vessels are in a vulnerable position.
Next, evaluate each option based on its definition.
Abruptio placenta is about placental separation, not vessel location.
Placenta previa is about the placenta's location, but the vessels are protected within it.
Placenta accreta is about the depth of placental attachment.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 13-28