Diagnostic Imaging Pathways - Suspected Ectopic Pregnancy

Transabdominal +/- Transvaginal Ultrasonography

• Pelvic ultrasonography (transabdominal US +/- transvaginal US) combined with measurement of serum ß-hCG levels, is an effective screening strategy for diagnosing ectopic pregnancy. 3-6
• Allows identification of an intrauterine pregnancy, which is the single most important finding for the exclusion of ectopic gestation as the presence of both intra- and extra-uterine pregnancy, is very rare. 1,3-6
• Compared to transabdominal ultrasonography, transvaginal ultrasonography is more sensitive and has a lower discriminatory zone (the range of serum ß-hCG concentrations above which gestational sac can be visualised consistently). This allows earlier diagnoses of intrauterine or ectopic pregnancies. 7-11
• Sensitivity for transvaginal ultrasonography ranges from 69 to 96% and specificity from 84 to 99%. 1,3,9,12
• When used in conjunction with serum ß-hCG levels, transvaginal ultrasound has comparable sensitivity and specificity for ectopic pregnancy to laparoscopy. 13
• Presence of an adnexal mass and/or free pelvic fluid is strong predictor of an ectopic pregnancy. 10,14-17
• Findings suggestive of ectopic pregnancy include: 13
  1. Fluid in the pouch of Douglas, an adnexal mass and an empty uterus.
  2. An adnexal mass, empty uterus or pseudogestational sac and a positive ß-hCG.
  3. Direct demonstration of ectopic fetus and fetal heart.
• Normal US does not exclude the diagnosis of ectopic pregnancy. 3,14,15
• Patients with indeterminate ultrasonography findings require further evaluation with quantitative ß-hCG levels +/- follow-up US or laparoscopy as about 15-20% of these patients will have a final diagnosis of ectopic pregnancy. 18,19

File Formats

Some documents for download on this website are in a Portable Document Format (PDF). To read these files you might need to download Adobe® Acrobat Reader.