Ectopic Pregnancy
Basics
Description
- Pregnancy implanted outside the uterine cavity.
- Subtypes:
- Tubal (95-97%; ampulla 55-80%, isthmus 12-25%, fimbria 5-17%)
- Abdominal
- Heterotopic (simultaneous intrauterine and ectopic)
- Ovarian
- Cervical
- Intraligamentary
Epidemiology
- Incidence: ~2 per 100 pregnancies in the US.
- 10% of first-trimester pain/bleeding presentations due to ectopic.
- Leading cause of first-trimester maternal deaths.
- Recurrence risk ~33% if prior ectopic.
- Increased incidence of nontubal ectopics due to IVF and cesarean scar pregnancies.
Etiology and Pathophysiology
- Impaired ovum transport due to ciliary dysfunction, scarring, or tubal lumen narrowing.
- Risk factors include PID, tubal surgery, IUD, assisted reproduction, tobacco, ciliary motility disorders.
Risk Factors
- History of PID or sexually transmitted infections.
- Prior ectopic pregnancy or tubal surgery.
- IUD use (if pregnancy occurs).
- Assisted reproductive technologies (IVF).
- Tobacco use.
- Endometriosis, Kartagener syndrome.
Prevention
- Reliable contraception, especially long-acting reversible contraception (LARC).
Diagnosis
History
- Classic triad: sudden-onset abdominal pain, missed or irregular menses, acute vaginal bleeding (present in >50%).
- Nausea, vomiting, shoulder pain (hemoperitoneum).
Physical Exam
- Abdominal tenderness ± rebound.
- Adnexal or cul-de-sac fullness.
- Cervical motion tenderness.
- Signs of shock if ruptured: pallor, tachycardia, hypotension.
Differential Diagnosis
- Miscarriage variants (threatened, inevitable, incomplete).
- Gestational trophoblastic disease.
- Appendicitis, PID, ovarian torsion, hemorrhagic cyst.
- Cervical pathology, trauma, infection.
Diagnostic Tests
Laboratory
- CBC, blood type and antibody screen.
- Serial quantitative serum beta-hCG.
Imaging
- Transvaginal ultrasound (TVUS) is gold standard.
- Failure to see intrauterine gestational sac when hCG >1,500-2,000 IU/L suggests ectopic or pregnancy of unknown location (PUL).
- MRI rarely used; helpful for abdominal or cesarean scar pregnancies.
Other Tests
- Serum progesterone (>20 ng/mL less likely ectopic but limited utility).
- Uterine aspiration/D&C for intrauterine chorionic villi.
- TVUS assessment of pelvic free fluid for hemoperitoneum.
Treatment
Medical Management
- Methotrexate (MTX) inhibits DNA synthesis by folate antagonism.
- Candidates: hemodynamically stable, unruptured, <3-4 cm sac, hCG <5,000 mIU/mL, no fetal heart activity.
- Single-dose protocol preferred: 50 mg/m² IM; repeat dose if hCG decline <15% between days 4 and 7.
- Multi-dose and two-dose protocols available.
- Monitor weekly quantitative hCG to zero.
- Avoid alcohol, NSAIDs, folate supplements during treatment.
- Contraindications: hemodynamic instability, rupture, anemia, severe organ dysfunction.
Surgical Management
- Indications: rupture, hemodynamic instability, contraindications to MTX, large sac, fetal heartbeat, failed medical therapy.
- Laparoscopy preferred.
- Salpingectomy preferred for uncontrolled bleeding, recurrent ectopic, damaged tube, sterilization desire.
- Salpingostomy considered to preserve fertility if contralateral tube compromised.
- Postoperative hCG monitoring essential after salpingostomy.
Expectant Management
- Selected stable patients with low and declining hCG (<1,500 mIU/mL) and no evidence of rupture.
- Requires close monitoring with serial hCG and TVUS.
Other Management
- Anti-D Rh immunoglobulin (50 µg) for Rh-negative women after surgery or significant bleeding.
Admission Criteria
- Hemodynamic instability.
- Suspected rupture.
- Severe abdominal pain.
- Inability to comply with outpatient follow-up.
Ongoing Care and Follow-Up
- Weekly hCG monitoring until undetectable.
- Pelvic ultrasound for persistent masses.
- Delay pregnancy at least 3 months after MTX.
- Pain management.
- Liver and renal function monitoring if repeated MTX doses needed.
Prognosis
- Fertility depends on preexisting tubal function and extent of damage.
- 66% chance of future intrauterine pregnancy in women able to conceive.
- Persistent infertility beyond 12 months warrants tubal evaluation.
Complications
- Hemorrhage, hypovolemic shock.
- Persistent trophoblastic tissue.
- Infection.
- Infertility.
- Transfusion-related risks.
- Disseminated intravascular coagulation (DIC) in massive hemorrhage.
Clinical Pearls
- 97% of ectopics are tubal.
- Always maintain high suspicion in pregnant patients with abdominal pain.
- Serial hCG and TVUS are crucial for diagnosis.
- Medical therapy with MTX effective in appropriate patients.
- Surgical management essential for rupture or unstable patients.