Women's Health

Pelvic ultrasound imaging by emergency physicians is highly effective in ruling out ectopic pregnancy

Emergency physicians can use bedside ultrasound imaging of the pelvis to quickly and accurately rule out ectopic pregnancy in women who are at high risk of this condition, according to a new meta-analysis of studies. Ectopic pregnancy, in which the embryo implants and begins developing outside of the uterus, is a common life-threatening condition that is the leading cause of first trimester maternal deaths. Because the chances of a woman having both a normal (intrauterine) and ectopic pregnancy at the same time is low (about 1 in 4,000 natural pregnancies), using ultrasound imaging to confirm a normal pregnancy can be used to rule out ectopic pregnancy, note the study authors. Emergency physicians would only need to be trained in pelvic ultrasound imaging, which can be done in the emergency department (ED), rather than requiring the patient to be transported to the radiology or gynecology department.

The researchers conducted a systematic literature review that identified 10 clinical studies of ED pelvic imaging involving 2,057 patients, 152 (7.5 percent) of whom had ectopic pregnancies. Based on the pooled data from the 10 studies, the authors calculated that the bedside imaging procedure had 99.3 percent sensitivity and a negative predictive value of 99.96 percent. The researchers concluded that ED physicians can learn to quickly rule out ectopic pregnancy without waiting for radiology consultation with a specialist. The researchers identified the 10 studies following a comprehensive literature search of citations from January 1966 to August 2009. The study was funded in part by the Agency for Healthcare Research and Quality (HS15569).

More details are in "Emergency physician ultrasonography for evaluating patients at risk for ectopic pregnancy: A meta-analysis," by John C. Stein, M.D., Ralph Wang, M.D., Naomi Adler, M.D., and others in the December 2010 Annals of Emergency Medicine 56(6); pp. 674-683.

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