Key Facts

Ectopic pregnancy is the implantation of a fertilised ovum outside the endometrial cavity. It is a common and potentially life-threatening condition requiring prompt diagnosis and management. Early recognition is essential to prevent tubal rupture and haemodynamic compromise.

Epidemiology

• Incidence: approximately 11 per 1,000 pregnancies in the UK
• Accounts for 0.5% of maternal deaths in the UK
• Peak incidence at age 25-34 years
• Incidence rising due to increased prevalence of risk factors and earlier detection

Aetiology

• Tubal factors: previous PID/salpingitis (especially Chlamydia trachomatis), previous tubal surgery, previous ectopic pregnancy (10-15% recurrence), tubal endometriosis
• Contraceptive factors: progesterone-only pill, IUCD/IUS in situ (does not increase absolute risk but proportion of ectopics increases), previous sterilisation failure
• Assisted reproduction: IVF/ICSI (2-5% ectopic rate)
• Other: smoking (dose-dependent, 2× risk), age >35 years, history of infertility

Pathophysiology

• 97% are tubal: ampullary (70%), isthmic (12%), fimbrial (11%), interstitial/cornual (2-4%)
• Non-tubal sites: ovarian (3%), cervical (<1%), caesarean scar, abdominal/peritoneal (rare)
• Damaged tubal epithelium (from PID, surgery) impairs ovum transport
• Growing ectopic erodes into tubal wall and blood vessels
• Tubal rupture causes intraperitoneal haemorrhage and haemodynamic compromise

Typical Presentation

• Amenorrhoea (6-8 weeks, though may have irregular bleeding mistaken for a period)
• Unilateral lower abdominal/pelvic pain
• Vaginal bleeding (usually scanty, dark brown, 'prune juice')
• Pain may be intermittent or constant

Ruptured Ectopic

• Sudden severe abdominal pain
• Shoulder tip pain (diaphragmatic irritation from haemoperitoneum)
• Haemodynamic compromise: tachycardia, hypotension, syncope
• Peritonism: guarding, rebound tenderness
• Cervical excitation on bimanual examination

Red Flags

• Haemodynamic instability (tachycardia, hypotension)
• Shoulder tip pain
• Syncope or collapse
• Peritonism
• Positive pregnancy test with acute abdomen

Bedside

• Urine pregnancy test (highly sensitive, positive in >99%)
• Observations: HR, BP, temperature
• Urinalysis

Bloods

• Serum βhCG: essential for management decisions; level >1,500 IU/L (discriminatory zone) without intrauterine pregnancy on TVS is highly suspicious
• Serial βhCG at 48 hours: in normal IUP, rises by ≥63%; in ectopic, often rises <63% or plateaus/falls
• FBC (haemoglobin for haemorrhage assessment)
• Group and save / crossmatch if haemodynamically unstable
• Serum progesterone: <20 nmol/L suggests non-viable pregnancy (limited utility)

Imaging

• Transvaginal ultrasound (TVS): first-line investigation (NICE NG126)
  • Intrauterine pregnancy visible from βhCG ~1,000-1,500 IU/L
  • Ectopic findings: adnexal mass, 'blob sign', 'bagel sign', tubal ring, free fluid in POD
  • Empty uterus with positive pregnancy test = pregnancy of unknown location (PUL)

Special Tests

• Diagnostic laparoscopy: definitive if diagnosis uncertain and patient symptomatic

Non-pharmacological

• Expectant management: suitable if βhCG <1,500 IU/L and declining, asymptomatic, able to return for follow-up
• Patient information: ectopic pregnancy warning symptoms, when to attend A&E
• Psychological support: early pregnancy loss counselling

Pharmacological

• Methotrexate 50mg/m² IM single dose:
  • Criteria: confirmed ectopic, βhCG <5,000 IU/L (some centres <3,000), no significant pain, adnexal mass <35mm, no fetal cardiac activity, no intrauterine pregnancy
  • Monitor βhCG on days 4 and 7: need ≥15% drop between days 4-7
  • If insufficient decline, consider second dose or surgery
  • Advise reliable contraception for 3 months after methotrexate (teratogenic)
  • Anti-D immunoglobulin for RhD-negative women if surgical management

Surgical/Interventional

• Laparoscopic salpingectomy: first-line surgical treatment (preferred if contralateral tube is healthy)
• Laparoscopic salpingotomy: considered if contralateral tube is damaged/absent (fertility-sparing); requires serial βhCG follow-up for persistent trophoblast
• Emergency laparotomy: for ruptured ectopic with haemodynamic instability

Referral Criteria

• All suspected ectopic pregnancies require urgent assessment in an early pregnancy assessment unit (EPAU)
• Emergency surgical referral if haemodynamically unstable
• Follow-up with serial βhCG until <5 IU/L (expectant or medical management)

• Maternal mortality: 0.2 per 1,000 ectopic pregnancies in the UK (significantly improved with early detection)
• Success rate of methotrexate (single dose): 65-95% (higher with lower initial βhCG)
• Subsequent intrauterine pregnancy rate: 60-70% after salpingectomy, 70-80% after salpingotomy
• Recurrence risk: 10-15% after one ectopic; 25% after two
• Persistent trophoblast after salpingotomy: 5-20% (requires serial βhCG monitoring)

Management Pathway Summary

βhCG Interpretation in Early Pregnancy