Ectopic Pregnancy

Make the Diagnosis: Ectopic Pregnancy

Prior Probability

Ectopic pregnancy has been reported to occur in up to 2.6% of all pregnancies.¹ Among pregnant patients with abdominal pain or vaginal bleeding, the prevalence is 15% (95% CI, 10%-22%).

Patients in Whom Ectopic Pregnancy Should Be Considered

Ectopic pregnancy should be considered in any woman who is pregnant and has either abdominal pain or vaginal bleeding. A risk factor for ectopic pregnancy (previous ectopic pregnancy, pelvic inflammatory disease, current intrauterine contraceptive device use, prior tubal or pelvic surgery, as well as infertility and assisted reproduction) is present in only half of affected patients.

Assessing the Likelihood of Ectopic Pregnancy

While pregnancy is confirmed with a serum human chorionic gonadotropin (hCG) test, there is no value that establishes the location of the pregnancy. Medical history findings or symptoms suggesting ectopic pregnancy all have likelihood ratios (LRs) of less than 1.5, so the clinician should rely on other findings. During a pelvic bimanual examination, the presence of cervical motion tenderness, an adnexal mass, or adnexal tenderness are the most useful findings (see Table 90-1). However, the absence of these findings do not have low enough LR to rule out an ectopic pregnancy. Transvaginal ultrasonography is the single best diagnostic modality for evaluating pregnant patients with abdominal pain or vaginal bleeding who may have an ectopic pregnancy (see Table 90-1).

Reference Standard Tests

The presence of an ectopic pregnancy is definitively established via surgical visualization or close clinical follow-up with serial transvaginal ultrasounds and serum hCGs Follow-up is important because 8% to 31% of pregnant women who have abdominal pain and/or vaginal bleeding will be diagnosed initially as having a pregnancy of unknown location (positive pregnancy test with no identifiable intrauterine or ectopic pregnancy), and many patients with ectopic pregnancy can be treated medically.²

References

Original Article: Does This Woman Have an Ectopic Pregnancy?

Clinical Scenarios

Case 1