Ectopic pregnancy
A fertilised ovum implants outside the uterine cavity, most often in the fallopian tube, which cannot safely expand to accommodate a growing pregnancy and eventually ruptures through its own vessels, a time-critical surgical emergency.
In a nutshell
A blastocyst implants in the fallopian tube, which cannot expand safely; as the pregnancy grows it stretches and eventually ruptures the tubal wall, tearing through the mesosalpinx vessels and causing sudden, severe intraperitoneal haemorrhage. It is a leading cause of early-pregnancy maternal death.
Classic presentation
Amenorrhoea of 6–8 weeks with unilateral pelvic pain and vaginal bleeding, plus shoulder tip pain and shock if ruptured.
Key points
- Any woman of reproductive age with abdominal pain must have a pregnancy test before any other cause is assumed.
- The tube has no tamponading muscle layer, so rupture causes immediate arterial bleeding into the peritoneum, not a slow ooze.
- Shoulder tip pain reflects diaphragmatic irritation from haemoperitoneum and is a red flag for significant bleeding.
- Serial beta-hCG at 48 hours: a rise under 63% or a plateau points away from a normal intrauterine pregnancy.
- Ruptured or haemodynamically unstable ectopic pregnancy is a surgical emergency: resuscitate and operate without delay.
- Methotrexate is reserved for small, unruptured pregnancies with low hCG and no fetal heartbeat; it is not for symptomatic or ruptured disease.
First-line investigation
Urine or serum beta-hCG to confirm pregnancy, followed by transvaginal ultrasound to localise it.
First-line management
If ruptured or shocked: resuscitate and proceed to urgent surgery. If stable and unruptured: choose expectant, medical (methotrexate) or surgical management based on size, hCG and symptoms.
Exam traps
- A negative urine pregnancy test in a woman with classic ectopic symptoms should still prompt serum beta-hCG if suspicion is high: urine tests can be falsely negative at very low titres.
- Pain classically precedes bleeding in ectopic pregnancy, the reverse pattern to typical miscarriage.
- A 'pregnancy of unknown location' with a plateauing or slowly rising hCG is managed as a probable ectopic until proven otherwise, even without a visible mass on scan.
Educational content pending clinical review. Not medical advice.