Subclassification of Indeterminate Pelvic Ultrasonograms: Stratifying the Risk of Ectopic Pregnancy

Abstract

Objective: To determine whether the subclassification of indeterminate ultrasound readings can identify patients who are at high, intermediate, or low risk for ectopic pregnancy. Methods: A retrospective review was made of consecutive ED patients presenting to an urban teaching hospital from August 1991 to December 1994 with abdominal pain and/or vaginal bleeding and a positive β‐hCG. Patients who had transvaginal ultrasonograms obtained during the ED visit that were read as indeterminate (no extrauterine findings of ectopic pregnancy and no intrauterine fetal pole or yolk sac) were eligible. Ultrasonograms were subclassified into 5 groups (empty uterus, nonspecific intrauterine fluid, echo‐genic debris within endometrial cavity, abnormal sac, normal sac) based on predetermined criteria. Patients were excluded if the final diagnosis could not be definitively determined. Results: 248 patients were identified. 20 patients were excluded because a final diagnosis could not be determined. Patients with an empty uterus [25/94 = 27% (95% CI 18–36%)] had the highest frequency of ectopic pregnancy. Patients with nonspecific intrauterine fluid collections [4/30 = 13% (95% CI 4–31%)] had the next highest frequency of ectopic pregnancy. Patients with intrauterine echogenic debris [2/39 = 5% (95% CI 1–11%)], abnormal sacs [1/36 = 3% (95% CI 1–9%)], or normal‐appearing sacs [0/29 = 0% (95% CI 0 ‐8%)] had low frequencies of ectopic pregnancy. Conclusion: Subclassification of indeterminate ultrasound readings identifies patients at high, intermediate, or low risk for ectopic pregnancy and should improve the diagnostic accuracy of ultrasonography in patients at risk for ectopic pregnancy. Key words: ectopic pregnancy; tubal pregnancy; intrauterine pregnancy; ultrasound; diagnosis.

The Predictive Value of Endometrial Stripe Thickness in Patients with Suspected Ectopic Pregnancy Who Have an Empty Uterus at Ultrasonography

“…2 A possible explanation for this finding is that, in the case of ectopic pregnancy with a high ␤-hCG value, the endometrium is under increased hormonal stimulation. In these cases, the visualized endometrial fluid likely represents blood.…”

“…Approximately 40% of patients with indeterminate ultrasound exams have empty endometrial cavities. 2 Of all patients with indeterminate ultrasound exams, this group is at highest risk for ectopic pregnancy. 2 In addition to ectopic pregnancy, possible pregnancy outcomes of patients with empty endometrial cavities include nonviable IUPs as well as normal but early (five weeks or less) IUPs.…”

“…2 Of all patients with indeterminate ultrasound exams, this group is at highest risk for ectopic pregnancy. 2 In addition to ectopic pregnancy, possible pregnancy outcomes of patients with empty endometrial cavities include nonviable IUPs as well as normal but early (five weeks or less) IUPs. The earliest ultrasound evidence of a normal IUP is the visualization of an intrauterine gestational sac.…”

Clinical information does not improve the performance of mathematical models in predicting the outcome of pregnancies of unknown location

“…They have also been referred to in the literature as nondiagnostic scans (1), pregnancies of uncertain site (2), and indeterminate transvaginal ultrasonography (3). Pregnancy of unknown location is a descriptive term rather than a pathologic diagnosis.…”

Fetal Outcomes in First Trimester Pregnancies with an Indeterminate Ultrasound

“…Although the risk of an ectopic pregnancy still exists, the majority of women with an indeterminate ultrasound do not have an ectopic pregnancy. Multiple studies by Dart et al in women with an indeterminate ultrasound in the ED showed retrospective ectopic rates of 14% (32 patients out of 228 enrolled) and 10.7% (33 patients out of 307 enrolled) (8,9). A prospective study following 628 women demonstrated fetal outcomes of normal intrauterine pregnancy at 16.9%, spontaneous abortion at 75.8%, and ectopic at 7.3% (after exclusion of 7 women with an elective abortion) (10).…”