A 29-year-old woman with 6 weeks amenorrhoea and mild spotting has beta-hCG of 3200 mIU/mL. Transvaginal ultrasound shows a small, centrally placed, irregular fluid collection within the endometrial cavity containing no yolk sac and no embryo. The most likely explanation is:

• A Early intrauterine pregnancy too early to show a yolk sac
• B Submucous fibroid with cystic degeneration
• C Anembryonic (blighted) ovum
• D Pseudogestational sac of an ectopic pregnancy ✓

Explanation

A pseudogestational sac is a blood or fluid collection within the decidua. It sits centrally in the cavity, has an irregular outline, and never contains a yolk sac or embryo, unlike a true sac which is eccentric, surrounded by echogenic chorionic villi, and contains a yolk sac. At beta-hCG well above the discriminatory zone, this finding should raise suspicion of ectopic pregnancy rather than reassure.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.