An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus, usually in the fallopian tubes. Symptoms include vaginal bleeding, abdominal pain, and amenorrhea. Diagnosis is confirmed through beta-hCG blood tests and ultrasound imaging showing no intrauterine pregnancy. Treatment depends on factors like rupture and includes emergency surgery, medical management with methotrexate, or expectant management for very low beta-hCG levels.