Normal intrauterine pregnancy is unlikely in emergency department patients with either menstrual days > 38 days or beta-hCG > 3,000 mIU/mL, but without a gestational sac on ultrasonography.

OBJECTIVE

To determine whether the absence of a gestational sac on transvaginal ultrasonography in patients with a quantitative beta-human chorionic gonadotropin (beta-hCG) > 3,000 mIU/mL and/or menstrual days > 38 excludes the diagnosis of a normal intrauterine pregnancy (IUP).

METHODS

A retrospective analysis was performed of ED patients evaluated from August 1991 to December 1994 at an urban teaching hospital. Patients presented with abdominal pain and/or vaginal bleeding and had a positive serum beta-hCG test. Patients who had transvaginal ultrasonographies performed during the ED visit that were read as indeterminate were reviewed. Menstrual days were determined by subtracting the date of the last normal menstrual period (LMP) from the ED visit date. ED beta-hCGs were quantified. Patients were excluded if the LMP or quantitative beta-hCG result was not available or if the final diagnosis could not be definitively determined.

RESULTS

248 patients met eligibility criteria; of these, 54 were excluded. Therefore, 194 patients were enrolled. Menstrual days ranged from 5 to 151, with a median of 54 days. Of 143 patients with menstrual days > 38 and no gestational sac by ultrasonography, only 4 (2.8%) had a final diagnosis of normal IUP. The menstrual days for the 4 normal IUPs were 39, 41, 42, and 59 days. beta-hCGs ranged from 19 to 151,926 mIU/mL, with a median of 2,410 mIU/mL. None of the 74 patients with a beta-hCG > 3,000 mIU/mL and no gestational sac by ultrasonography had a final diagnosis of normal IUP.

CONCLUSION

In patients with either a beta-hCG > 3,000 mIU/mL or menstrual days > 38 and no gestational sac by transvaginal ultrasonography, the likelihood of a normal IUP is low.