A 30-year-old woman thought to be 9 weeks pregnant undergoes transvaginal ultrasound. The mean gestational sac diameter measures 28 mm but no embryo or yolk sac is identified within the sac. What is the correct interpretation?
- A Definitive early pregnancy failure (missed abortion) ✓
- B Normal very early pregnancy, repeat scan after 1 week
- C Pseudogestational sac of ectopic pregnancy
- D Subchorionic hemorrhage threatening viability
Correct answer: A. Definitive early pregnancy failure (missed abortion)
Explanation
By the revised criteria of the Society of Radiologists in Ultrasound, a mean sac diameter of 25 mm or more with no embryo is diagnostic of failed pregnancy, as is a crown-rump length of 7 mm or more without cardiac activity. These findings are definitive, so repeat scanning is unnecessary. B pseudogestational sac lacks these dimensions and typically contains no yolk sac at all.
Reference: Doubilet PM et al, NEJM 2013 diagnostic criteria for early pregnancy failure, NEJM 369:1443-51 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.