Ectopic Pregnancy: Causes, Risk Factors & Prevention

Ectopic pregnancy (EP) = implantation outside uterine cavity (95%+ in fallopian tube). Incidence: 1–2% of pregnancies. Leading cause of 1st trimester maternal mortality.

Risk Factors (Strength of Association)

High Risk (OR >4)	Moderate Risk (OR 2–4)	Low Risk (OR 1.5–2)
Prior EP	Tubal surgery (ligation reversal, lysis)	Infertility / ART
Tubal damage (PID, chlamydia, gonorrhea)	Endometriosis	Smoking (dose-dependent)
DES exposure in utero	IUD in situ (if pregnant, 50% EP)	Age >35
Tubal pathology (congenital, adhesions)	Multiple sexual partners (proxy for STI)	Prior abdominal/pelvic surgery

Pathophysiology

Impaired tubal transport (cilia damage, smooth muscle dysfunction, adhesions) + embryo-tubal interaction failure → implantation in tube. Half of EPs have no identifiable risk factor.

Prevention

• STI Prevention: Condoms, screening, prompt treatment of PID.
• Smoking Cessation: Only modifiable behavioral risk factor.
• IUD Counseling: If pregnant with IUD → urgent US for location.
• Early Prenatal Care: Early US confirms intrauterine location; early EP detection → medical management option.

Clinical Presentation

• Abdominal/pelvic pain (unilateral, sharp), vaginal bleeding, amenorrhea.
• Shoulder tip pain (diaphragmatic irritation from hemoperitoneum) → rupture sign.
• Syncope, hypotension (rupture) → EMERGENCY.

Diagnosis & Management

• Transvaginal US + serial β-hCG (discriminatory zone ~1500–2000 mIU/mL).
• Methotrexate (single/multi-dose) if unruptured, hCG <5000, no fetal cardiac activity, compliant.
• Laparoscopic Salpingectomy (preferred) or Salpingostomy (if contralateral tube damaged/desire fertility).
• RhIg if Rh-negative.

Future fertility: ~60–70% conceive within 18 mo after one EP; higher after salpingectomy vs salpingostomy if other tube normal. Early US in next pregnancy.