OG9.4 | Ectopic Pregnancy and Acute Abdomen — Summary & Reflection

KEY TAKEAWAYS

Ectopic pregnancy = implantation outside the uterine cavity; 95–98% tubal; ampullary ~70% (most common); isthmic ~12% (ruptures earliest); cornual/interstitial ~2–3% (most dangerous — dual blood supply, late rupture, massive haemorrhage). Classic triad: amenorrhoea, unilateral lower abdominal pain, scanty dark vaginal bleeding. Cervical os is CLOSED; cervical excitation tenderness + adnexal mass on pelvic exam. Differential: threatened/inevitable abortion (os status distinguishes), appendicitis (fever, RIF, raised WBC), ovarian cyst accident, PID. Investigation: serum β-hCG + TVS; discriminatory zone ~1500–2000 IU/L on TVS — empty uterus above this = presumed ectopic; serial β-hCG 48h for PUL (sub-optimal rise <53% = failing/ectopic). Management: unstable → emergency surgery (do not delay for imaging). Stable + criteria met → MTX 50 mg/m² IM: criteria = stable + β-hCG <5000 IU/L + no cardiac activity + mass ≤3.5 cm + no contraindications; MTX fails if <15% decline Day 4–7 → repeat dose or surgery. Surgery: salpingostomy (tube-conserving) when contralateral tube is absent/damaged; salpingectomy when contralateral tube is normal or tube is ruptured/severely damaged. Anti-D 300 µg for all Rh-negative women.

REFLECT

You are the on-call doctor at 11 PM. A woman with amenorrhoea for 6 weeks presents with left-sided pelvic pain and a positive pregnancy test. Her vital signs are normal. The TVS shows an empty uterus and a 2 cm left adnexal mass. β-hCG is 1,200 IU/L. Reflect on: How certain are you that this is an ectopic? What is the safest management plan for tonight? What will you tell her about what to watch for, and what would make you call her back to the hospital urgently? How does the concept of a 'pregnancy of unknown location' change the way you counsel this woman — and how do you balance the need to act decisively with the risk of treating a potentially viable early intrauterine pregnancy with a teratogenic drug?