Ectopic pregnancy refers to the implantation of a fertilized egg in a location outside of the uterine cavity, including the fallopian tubes(approximately 97.7%), cervix, ovary, cornual region of the uterus, and abdominal cavity. Of tubal pregnancies, the ampulla is the most common site of implantation (80%), followed by the isthmus (12%), fimbria (5%), cornua (2%), and interstitia (2-3%).
The classic clinical symptoms of ectopic pregnancy are abdominal pain, amenorrhea, vaginal bleeding. Unfortunately, only about 50% of patients present with all 3 symptoms. Patients may present with other symptoms common to early pregnancy (eg, nausea, breast fullness).
The most common site of ectopic implantation is a fallopian tube, followed by the uterine cornua. Pregnancies in the cervix, a cesarean delivery scar, an ovary, the abdomen, or fallopian tube interstitium are rare. Heterotopic pregnancy (simultaneous ectopic and intrauterine pregnancies) occurs in only 1/10,000 to 30,000 pregnancies but may be more common among women who have had ovulation induction or used assisted reproductive techniques such as in vitro fertilization and gamete intrafallopian tube transfer (GIFT); in these women, the overall reported ectopic pregnancy rate is ≤ 1%.
The prevalence of ectopic pregnancy among women who go to an emergency department with first trimester bleeding, pain, or both ranges from six to 16 percent. The overall incidence of ectopic pregnancy increased during the mid-twentieth century, plateauing at approximately almost 20 per 1000 pregnancies in the early 1990s, the last time national data were reported by the Centers for Disease Control. This rising incidence is strongly associated with an increased incidence of pelvic inflammatory disease.