Definition
Any gestation in which implantation occurs at a location other than the endometrial lining (Figure 5.1).
Epidemiology and risk factors
- Incidence in the UK and USA is roughly 20/1000 conceptions.
- Mortality. Ten percent of pregnancy-related maternal deaths (most common cause of death in the first half of pregnancy).
- Risk factors (Figure 5.2). Past history of pelvic inflammatory disease (see Chapter 8), especially that caused by Chlamydia trachomatis, is most important. However, >50% of patients have no risk factors.
- Etiology. The major cause of ectopic pregnancy is acute salpingitis: permanent agglutination of the folds of the endosalpinx can allow passage of the smaller sperm while the fertilized ovum (morula) gets trapped in blind pockets formed by adhesions. Contraception failure, hormonal alterations, and previous termination also contribute to an increased risk of ectopic pregnancy.
Symptoms and signs
Frequently the diagnosis is established before symptoms or signs develop due to the use of early serum testing and vaginal sonography.
- Abdominal pain, absence of menses, and irregular vaginal bleeding (usually spotting) are the main symptoms.
- Ruptured ectopic pregnancies cause shoulder pain in 10–20% of cases as a result of diaphragmatic irritation from the hemoperitoneum. Syncope also may occur due to intense, sudden pain. Other symptoms may include dizziness and an urge to defecate.
- The most common presenting sign in a woman with symptomatic ectopic pregnancy is abdominal tenderness. Half of women will have a palpable adnexal mass. Profound intraperitoneal hemorrhage will lead to tachycardia and hypotension.
Diagnosis (Figure 5.3)
A thorough history and physical examination are essential. The extent should be dictated by the severity of symptoms at presentation.
- Serial quantitative levels of the β-subunit of human chorionic gonadotropin (βhCG)
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