Quantitative B-hCG levels less than 1000 mIU/mL in patients with ectopic pregnancy: pelvic ultrasound still useful.

The purpose of this study was to determine if pelvic ultrasound was useful in suggesting the diagnosis of ectopic pregnancy in patients with a quantitative B-hCG level less than 1000 mIU/mL. We performed a retrospective review of all patients evaluated and diagnosed with ectopic pregnancy in the emergency departments of seven area hospitals during a ten month period. Sixty-four patients with a confirmed diagnosis of ectopic pregnancy, a pelvic ultrasound, and a quantitative B-hCG level were included in the study. Eighteen (28%) of these patients had a quantitative B-hCG less than 1000 mIU/mL. Sixteen of the eighteen patients (89%) with a B-hCG level less than 1000 mIU/mL had sonographic findings suggestive of ectopic pregnancy, such as fluid in the cul-de-sac, or a complex adnexal or cystic mass. Overall, 25% of all patients diagnosed with an ectopic pregnancy during this time period had a quantitative B-hCG level less than 1000 mIU/mL and an ultrasound suggestive for ectopic pregnancy. Pelvic ultrasound is useful as a screening tool in the initial evaluation of suspected ectopic pregnancy, even when the quantitative B-hCG level is below 1000 mIU/mL.