Description

Ectopic: pregnancy implanted outside the uterine cavity; subtypes include:

• Tubal—pregnancy implanted in the fallopian tube
• Abdominal—pregnancy implanted intra-abdominally, usually after tubal abortion or rupture of tubal ectopic pregnancy
• Heterotopic pregnancy—implanted intrauterine pregnancy (IUP) AND a separate pregnancy implanted outside the uterine cavity
• Ovarian—implantation of pregnancy in ovarian tissue
• Cervical—implantation of pregnancy in cervix
• Intraligamentary—implantation of pregnancy within the broad ligament

Epidemiology

Incidence

• Incidence is around 2 per 100 pregnancies in the United States (1). About 1 in 10 first-trimester pregnancies presenting to the emergency department with pain and/or bleeding are due to ectopic pregnancy. In the United States, ectopic pregnancy is the leading cause of first-trimester maternal deaths.
• Heterotopic pregnancy, although rare (1:30,000), occurs with greater frequency (1/1,000) in women undergoing in vitro fertilization (IVF); increasing incidence of nontubal, and particularly cesarean scar ectopic pregnancies, due in part to more cesarean sections and more IVF
• ~33% recurrence rate if prior ectopic pregnancy

Etiology and Pathophysiology

95–97% of ectopic pregnancies occur in the fallopian tube: 55–80% in the ampulla, 12–25% in the isthmus, and 5–17% in the fimbria. One cause of tubal pregnancy is impaired movement of the fertilized ovum to the uterine cavity due to dysfunction of the tubal cilia, scarring, or narrowing of the tubal lumen.

Risk Factors

• History of pelvic inflammatory disease (PID), endometritis, or current gonorrhea/chlamydia infection, pelvic adhesive disease (infection or prior surgery)
• Previous ectopic pregnancy, history of tubal surgery (~33% of pregnancies after tubal ligation are ectopic.)
• Use of an intrauterine device (IUD): IUD reduces absolute risk (and therefore number) of ectopic pregnancies, but in a patient with an IUD in place presenting with a pregnancy, there is an increased likelihood that the pregnancy is ectopic, compared with a patient without an IUD.
• Use of assisted reproductive technologies
• Tobacco use; patients with disorders that affect ciliary motility may be at increased risk (e.g., endometriosis, Kartagener syndrome).

General Prevention

Reliable contraception (especially long-acting reversible contraception [LARC] methods)