On transvaginal ultrasound at 6 weeks amenorrhoea, which finding favours a true intrauterine gestational sac over a pseudogestational sac associated with ectopic pregnancy?
- A Location of the fluid collection in the midline of the cavity
- B Presence of the double decidual sac sign ✓
- C Absence of a yolk sac within the collection
- D Irregular outline of the fluid collection
Correct answer: B. Presence of the double decidual sac sign
Explanation
The double decidual sac sign, produced by the concentric rings of decidua capsularis and decidua parietalis surrounding the sac, confirms a true intrauterine gestation. B pseudogestational sac is a simple fluid collection within the cavity, lacks the double decidual reaction, a yolk sac and a fetal pole, and may change shape or disappear on follow-up. Seeing a yolk sac is itself strong evidence against a pseudosac.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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