Ectopic Pregnancy – Comprehensive Exam Notes

Ectopic Pregnancy (EP) = implantation of the fertilised ovum at any site outside the uterine cavity.
- ≥ $90\%$ occur within the fallopian tube ⇒ often called “tubal pregnancies”.
- Within tubal EPs, ≈ $70\%$ implant in the ampulla (widest segment).
Core mechanism: obstruction to, or slowing of, ovum transport through the tube.
- Failure of coordinated peristalsis & ciliary action of tubal epithelium.
- Tubal scarring from prior infections or surgery is the most common precipitant.
Consequences
- Limited vascular/elastic capacity of extra-uterine sites → risk of rupture, intra-abdominal haemorrhage, hypovolaemic shock.
- Potential compromise of future fertility if tube damaged or removed.

Common locations in descending frequency:
1. Ampulla
2. Isthmus
3. Interstitium (cornual)
4. Fimbria
5. Tubo-ovarian ligament
6. Ovary
7. Abdominal cavity
8. Cervix (external os)
Rare but reported sites: within a prior Caesarean scar, within uterine cornua, attached to peritoneal surfaces.
Ovary, abdominal cavity and cervix together comprise < $10\%$ of all EPs but carry higher diagnostic delay.

Direct factors interfering with tubal transit
- Tubal scarring secondary to pelvic inflammatory disease (PID) caused by $N.\ gonorrhoeae$ or $Chlamydia$ spp.
- Previous salpingitis (acute/sub-acute).
- Prior tubal or pelvic surgery (e.g., salpingostomy, sterilisation reversal).
Reproductive & gynaecological history
- Previous induced or spontaneous pregnancy loss.
- History of infertility treatments.
- Presence of uterine fibroids distorting anatomy.
Contraceptive & iatrogenic factors
- Current or recent intra-uterine device (IUD) use.
- Post-sterilisation pregnancy.
Lifestyle & medical
- Cigarette smoking (dose-dependent impairment of tubal ciliary motility).
NOTE: > $50\%$ of women with EP may have no identifiable risk factor, hence high index of suspicion is vital.

Classic triad: abdominal pain, amenorrhoea, vaginal bleeding (occurs in ~ $50\%$ ).
Timing
- Symptoms typically 6–8 weeks after last normal menstrual period (LNMP).
Pain characteristics
- Unilateral pelvic/abdominal pain ± radiation to shoulder tip (phrenic nerve irritation by intraperitoneal blood).
- Sudden severe pain may indicate rupture.
Additional symptoms/signs
- Dizziness, syncope, urge to defecate (cul-de-sac blood pooling).
- Tender abdomen, cervical motion tenderness, adnexal mass on bimanual exam.
- Vital-sign patterns: hypotension & tachycardia (haemorrhage) OR paradoxical bradycardia (vagal response).
- Usually afebrile unless concurrent infection.
- Scant dark bleeding from cervical os.

Point-of-care / ED algorithm
1. Perform transvaginal (TVS) or transabdominal sonography (TAS) at presentation or within 48 h.
2. Quantitative serum $\beta$ -hCG.
- Discriminatory zone: >1500\,mIU\/mL (TVS) or >3000\,mIU\/mL (repeat scan needed if below).
1. Interpretations
  • Definite EP (extra-uterine gestational sac) → OB consult; consider methotrexate vs surgery.
  • Definite IUP → routine prenatal follow-up.
  • Indeterminate → serial $\beta$ -hCG every 48 h ± repeat U/S until trend distinguishes EP, miscarriage or viable IUP.
Differential diagnoses to exclude
- Ruptured corpus luteum cyst, incomplete/ missed abortion, appendicitis, salpingitis, ovarian torsion, renal colic, normal early pregnancy.

Candidate criteria
- Haemodynamically stable & reliable for follow-up.
- Unruptured EP size < $4\,cm$ on U/S.
- $\beta$ -hCG <10{,}000\,mIU\/mL.
- No detectable intra-uterine pregnancy (IUP).
- Normal renal & hepatic function tests.
Regimens
- Single-dose: 50\,mg\/m^2 IM; monitor $\beta$ -hCG on day 4 & 7.
- Adequate response = ≥ $15\%$ fall from day 4 → day 7.
- If < $15\%$ drop → repeat dose or proceed to surgery.
Adjuvant/alternate drugs occasionally researched: prostaglandins, misoprostol, actinomycin-D.
Patient counselling
- Avoid folic-acid supplements/alcohol (↓MTX efficacy).
- Report abdominal pain (could be rupture or MTX effect).

Indications
- Haemodynamic instability, evidence of rupture, contraindication or failure of MTX, desire for definitive treatment.
Procedures
• Linear salpingostomy (unruptured EP) – incision over gestation, evacuation, secondary healing → preserves fertility.
• Salpingectomy (ruptured EP or severely damaged tube) – partial or total removal via laparoscopy or laparotomy.
Peri-operative points
- Control of haemorrhage paramount.
- Rh-negative women receive $\rho$ -immunoglobulin $300\,\mu g$ IM within 72 h.
- Serial $\beta$ -hCG until undetectable regardless of approach to exclude persistent trophoblastic tissue.

Initial
- Vital signs, pain scale, orthostatic measurements for occult blood loss.
- Evaluate LMP, pregnancy history, risk factors.
- Obtain IV access, baseline labs, cross-match if bleeding.
Ongoing
- Administer analgesics & antiemetics.
- Prepare & administer MTX; monitor for side-effects (stomatitis, GI upset).
- Pre-op & post-op care if surgical.
Education
- Warning signs of rupture: sudden worsening pain, shoulder tip pain, dizziness, fainting.
- Explain need for serial $\beta$ -hCG & U/S until resolved.
Psychosocial
- Provide emotional support; acknowledge grief over pregnancy loss and fear about future fertility.
- Facilitate counselling or support groups.

Risk-reduction strategies
- Limit number of sexual partners; consistent condom use.
- Early testing & full treatment of STIs to prevent PID.
- Smoking cessation during reproductive years.
IUD users
- Teach recognition of PID symptoms: pelvic pain, fever, unusual discharge ⇒ seek prompt care.
Preconception & early pregnancy
- Advise early prenatal visit for confirmation of intra-uterine location via TVS.

EP is non-viable; continuation endangers maternal life ⇒ consensus on treatment necessity.
Decision between MTX vs surgery balances maternal risk, future fertility, resource availability.
Rh iso-immunisation prevention is a standard of care; omission would have serious future pregnancy implications.
Cultural or religious concerns around termination should be addressed with sensitivity & accurate medical facts.

Tubal location: $\approx 90\%$ of all EPs.
Ampullary implantation: $\approx 70\%$ of tubal EPs.
Diagnostic $\beta$ -hCG thresholds:
- >1500\,mIU\/mL (TVS discriminatory zone).
- >3000\,mIU\/mL for reliable TAS.
Medical management cut-offs:
- Gestational sac < $4\,cm$ .
- $\beta$ -hCG <10{,}000\,mIU\/mL.
- Target ≥ $15\%$ reduction from day 4–7 post-MTX.

Rising rates of Chlamydia & gonorrhoea infections globally → steady increase in EP incidence.
Assisted reproductive technologies (ART) elevate EP risk via tubal factor infertility and manipulation of gametes.
Emergency clinicians utilise point-of-care ultrasound (POCUS) to expedite triage & reduce morbidity.
Public health initiatives focusing on STI prevention indirectly lower EP prevalence.

Think EP in any reproductive-age woman with pain + bleeding + positive pregnancy test until proven otherwise.
Early TVS + quantitative $\beta$ -hCG is diagnostic backbone.
Methotrexate is safe & effective in selected stable cases; surgery lifesaving when ruptured.
Serial $\beta$ -hCG mandatory post-treatment to confirm resolution.
Prevention hinges on PID avoidance, smoking cessation, and early prenatal confirmation of gestational location.