Ectopic Pregnancy

American Family Physician,  Feb 15, 2000  by Josie L. Tenore

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Endometriosis, tubal surgery and pelvic surgery result in pelvic and tubal adhesions and abnormal tubal function. The fallopian tubes may also be affected by other, less clearly understood causes of infertility, as well as many of the hormones that are administered to aid ovulation and improve fertility.10

In utero exposure to diethylstilbestrol (DES) is associated with uterotubal anomalies ranging from gross structural abnormalities such as a double uterus to more subtle microscopic abnormalities resulting in tubal dysfunction.1,10,11 Any uterotubal anomalies, with or without DES exposure, increase the risk of ectopic pregnancy.

Cigarette smoking has an independent and dose-related effect on the risk of ectopic pregnancy. Cigarette smoking is known to affect ciliary action in the nasopharynx and respiratory tract. A similar effect may occur within the fallopian tubes.3,12

Multiple sexual partners, early age at first intercourse and vaginal douching are often considered risk factors for ectopic pregnancy. The mechanism of action for these risk factors is indirect, in that they are markers for the development of sexually transmitted disease, ascending infection, or both.3,10

Clinical Findings

Recent technologic improvements have made it possible to diagnose ectopic pregnancy earlier. This has altered the clinical presentation from that of a life-threatening surgical emergency to a less severe constellation of signs and symptoms.

Historically, the hallmark of ectopic pregnancy has been abdominal pain with spotting, usually occurring six to eight weeks after the last normal menstrual period. This remains the most common presentation of tubal pregnancy in symptomatic patients. Other presentations depend on the location of the ectopic pregnancy. Less commonly, ectopic pregnancy presents with pain radiating to the shoulder, vaginal bleeding, syncope and/or hypovolemic shock.

Physical findings include a normal or slightly enlarged uterus, pelvic pain with movement of the cervix and a palpable adnexal mass. Findings such as hypotension and marked abdominal tenderness with guarding and rebound tenderness suggest a leaking or ruptured ectopic pregnancy. Case reports indicate that viable abdominal ectopic pregnancies may be discovered at cesarean section, albeit rarely.13

Diagnostic Evaluation

Between 40 and 50 percent of ectopic pregnancies are misdiagnosed at the initial visit to an emergency department.4,14 Failure to identify risk factors is cited as a common and significant reason for misdiagnosis.4 A proper history and physical examination remain the foundation for initiating an appropriate work-up that will result in the accurate and timely diagnosis of an ectopic pregnancy.

Identification of risk factors can raise the index of suspicion and lend significance to otherwise minor physical findings. For example, subtle changes in vital signs, such as mild tachycardia or lower than usual blood pressure, should prompt further investigation. Scoring systems have been proposed to facilitate earlier diagnosis of ectopic pregnancy by indicating the level of risk as a function of weighted risk factors.15