Pregnancy of unknown location with worsening pain — MRCEM SBA MCQ

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HardProcedures, imaging and diagnosticsPregnancy of unknown location with worsening painMRCEM SBA

A 30-year-old woman returns to the emergency department 48 hours after assessment for light vaginal bleeding in early pregnancy. Her initial transvaginal ultrasound showed no intrauterine or ectopic pregnancy and no free fluid. Her serum hCG has risen from 800 IU/L to 1,360 IU/L. Since this morning, she has developed worsening left iliac fossa pain. Her blood pressure is 118/74 mmHg, pulse 94/min, and she has localised tenderness without guarding. She has no shoulder-tip pain or syncope. What is the most appropriate diagnostic plan now?

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Correct answer: B — Obtain urgent gynaecology review and repeat transvaginal ultrasonography.

The first scan established a **pregnancy of unknown location**, not an intrauterine pregnancy. Although hCG has risen by 70% over 48 hours—a pattern associated with a likely developing intrauterine pregnancy—it cannot establish where the pregnancy is. Her new, worsening unilateral pain takes priority over the reassuring-looking hCG trend. She needs urgent clinical reassessment by gynaecology, with repeat transvaginal ultrasound to investigate the pregnancy’s location and assess for ectopic pregnancy. ([nice.org.uk](https://www.nice.org.uk/guidance/NG126/chapter/diagnosis-of-viable-intrauterine-pregnancy-and-of-tubal-ectopic-pregnancy)) **A** delays assessment of a clinically changed patient; serial hCG does not determine pregnancy location. **C** reflects the usual interval-scan pathway after an hCG rise above 63%, but applies when symptoms have not worsened. **D** cannot distinguish a viable intrauterine from an ectopic pregnancy in this pathway; NICE advises against using progesterone as an adjunct to serial hCG. **E** may become appropriate if reassessment identifies a surgical emergency, but her current stability and absence of peritonism do not make laparoscopy the best *initial diagnostic step*. The key exception is that a favourable hCG rise must not override new symptoms while pregnancy location remains unknown. ([nice.org.uk](https://www.nice.org.uk/guidance/NG126/chapter/diagnosis-of-viable-intrauterine-pregnancy-and-of-tubal-ectopic-pregnancy))

Reference: NICE NG126: Diagnosis of viable intrauterine pregnancy and of tubal ectopic pregnancy, sections 1.5 and 1.8 (17 June 2026) — https://www.nice.org.uk/guidance/NG126/chapter/diagnosis-of-viable-intrauterine-pregnancy-and-of-tubal-ectopic-pregnancy NICE NG126: Management of tubal ectopic pregnancy, sections 1.15 and 1.16 (17 June 2026) — https://www.nice.org.uk/guidance/NG126/chapter/management-of-tubal-ectopic-pregnancy