Ectopic pregnancy--Part II: Diagnostic procedures and imaging.

Ectopic pregnancy is an increasingly common and potentially catastrophic condition in which the patient often presents to the ED with abdominal pain or vaginal bleeding. Recent developments in the laboratory (sensitive beta hCG assays, progesterone assays), in ultrasonography (transvaginal probes, Doppler ultrasonography), and in the combination of modalities (discriminatory zone of beta hCG for ultrasonographic evidence of IUP) have allowed the earlier diagnosis of ectopic pregnancy, with the potential for a reduction in maternal mortality and morbidity. Understanding the strengths and limitations of the variety of diagnostic modalities available will allow the clinician to formulate a rational strategy for the early diagnosis of ectopic pregnancy. Numerous algorithms have been developed. All begin with high clinical suspicion for women of reproductive age with abdominal/pelvic pain or vaginal bleeding. Pregnancy testing with a sensitive beta hCG qualitative test is next. For stable patients found to be pregnant, sonography generally follows (often first transabdominally then transvaginally). Unstable patients require immediate resuscitation and gynecology consultation; invasive diagnostic methods may supplant laboratory studies and sonography. Unclear cases may necessitate the use of quantitative beta hCG (discriminatory zone), other pregnancy hormones (progesterone), invasive procedures (laparoscopy, culdocentesis, D&C), or observation (serial beta hCGs). A suggested algorithm incorporating these elements is shown (Fig. 1).