Efficacy of transabdominal ultrasound examination in the diagnosis of early pregnancy complications in an emergency department.

OBJECTIVE: To assess the value of ultrasound in an emergency department in the diagnosis of early pregnancy complications, the efficacy of a study protocol in identifying ectopic pregnancies, and the agreement on ultrasound findings among emergency department staff and gynaecologists.
METHODS: All women presenting with early pregnancy complications had a transabdominal ultrasound scan performed by the attending doctor and checked by a senior doctor. The ultrasound findings were classified as normal intrauterine pregnancy (IUP), probable abnormal pregnancy, definite ectopic pregnancy, no definite IUP, and other. Women with clinical and ultrasound findings compatible with threatened abortion were referred to a gynaecologist, or were admitted if findings suggested abnormal or ectopic pregnancy, or if a definite IUP could not be confirmed on ultrasound scan. For patients who were admitted or referred, a transvaginal ultrasound scan was performed by the attending gynaecologist. The findings of the gynaecologist were used as the gold standard.
RESULTS: 151 cases were enrolled during a four month study period. Ultrasound findings in the emergency department included definite IUP in 95 (63%), probable abnormal IUP in 20 (13%), no definite IUP in 23 (21%), and other findings in four (3%). For evaluating the presence or absence of IUP, sensitivity of the initial scan was 82% (95% confidence interval 76% to 88%) and specificity 92% (88% to 96%). Agreement between junior and senior emergency department doctors on their ultrasound findings was 81% (75% to 87%) and between emergency department senior staff and gynecologists 85% (79% to 91%). The diagnoses made in the emergency department were thought to be compatible with the final assessments by gynaecologist in 72% (65% to 79%). Using either no definite IUP or other findings as a positive screening test for ectopic pregnancy, the sensitivity, specificity, positive predictive value, and negative predictive value were 80% (74% to 86%), 78% (71% to 85%), 12% (7% to 17%), and 99% (97% to 100%), respectively.
CONCLUSIONS: Transabdominal ultrasound performed in the emergency department is useful in screening for early pregnancy complications. Ectopic pregnancy should be suspected when no IUP is found on preliminary scanning.