Early pregnancy pain and bleeding with a pregnancy of unknown location — structured SAQ (15 marks)

(a) The label, its definition and the four outcomes (4 marks)

One mark for the correct label with an accurate definition, then one mark for each pair of correctly named outcomes, to a maximum of four. ^[2]

• Label: pregnancy of unknown location (PUL). A positive pregnancy test with no intrauterine pregnancy, no extrauterine pregnancy and no retained products of conception on a good-quality transvaginal scan. It is a classification, not a diagnosis.^[2]
• Outcome 1 — visualised intrauterine pregnancy. The commonest; the pregnancy was simply too early to see.
• Outcome 2 — spontaneously resolved (failed) PUL. hCG falls to negative and nothing is ever visualised.
• Outcome 3 — visualised ectopic pregnancy. In the largest implementation cohort, 320 of 2625 PULs (about 12%) were ectopic.^[3]
• Outcome 4 — persisting PUL. hCG neither falls convincingly nor rises to visualisation; later sub-classified as non-visualised ectopic, treated persistent PUL, resolved persistent PUL, or histologic intrauterine pregnancy.^[2]

A candidate who writes "possible ectopic" without the formal label and definition scores at most one mark here. ^[2]

(b) Investigation plan for the next 48 hours (4 marks)

One mark each, maximum four. ^[1]

• A second serum hCG as near as possible to 48 hours after the first, and no earlier. Only two measurements initially; further sampling needs senior review.^[1]
• Blood group and antibody screen at the first venepuncture, so the rhesus decision is not delayed.^[1]
• State explicitly that hCG will NOT be used to locate the pregnancy — only to assess trophoblastic proliferation and guide the next step.^[1]
• Name the action attached to each band before she leaves: rise greater than 63% means a scan in 7 to 14 days; fall greater than 50% means a urine pregnancy test 14 days after the second sample; any intermediate change means review in the early pregnancy assessment service within 24 hours.^[1]

Additional credit for noting that her treated chlamydia is a recognised risk factor for ectopic pregnancy and raises her prior probability. ^[5]

(c) The repeat hCG result and its classification (4 marks)

• Calculate and state the change. From 940 to 1180 IU/L is a rise of 240 IU/L, which is a 25.5% rise over 48 hours. (1 mark)
• Classify it. This is a rise of less than 63% — the intermediate band. It is neither a reassuring rise nor a convincing fall, and it is the pattern most associated with ectopic pregnancy. (1 mark)^[1]
• Management: clinical review in the early pregnancy assessment service within 24 hours, with senior involvement, repeat transvaginal ultrasound and reassessment of symptoms and examination findings. (1 mark)^[1]
• Justify why this is not a viable intrauterine pregnancy pattern: the slowest rise compatible with a viable intrauterine pregnancy is about 53% over two days, so a 25.5% rise falls well below it. (1 mark)^[4]

Full marks require the arithmetic, the band name, the 24-hour interval and the physiological justification. A candidate who simply writes "repeat in 48 hours" loses three of the four marks and, in the examiner's mind, has just missed an ectopic pregnancy. ^[1][4]

(d) Counselling and safety-netting to document today (3 marks)

One mark each, maximum three. ^[1][6]

• Explain the label honestly: we know she is pregnant but we cannot yet see where; this is common, most turn out fine, and until we locate it we must treat an ectopic pregnancy as possible.^[1]
• Written information plus a 24-hour contact number, given regardless of the hCG level, with explicit return criteria — worsening or one-sided pain, shoulder-tip pain, heavy bleeding, dizziness or fainting.^[1]
• A booked, named follow-up with the date and time of the repeat hCG and who will phone her with the result, plus acknowledgement of the emotional impact and an offer of support. Post-traumatic stress criteria were met by 29% of women one month after early pregnancy loss and 18% at nine months.^[6]