Study objective: To determine the prevalence of unrecognized pregnancy in the emergency department and to ascertain if patient history can effectively detect unrecognized pregnancies.
Design: Prospective study.
Setting: Urban ED with annual census of 40,000.
Participants: One hundred ninety-one consecutive women meeting inclusion criteria.
Interventions: All participants completed a menstrual/sexual history questionnaire and had a urine pregnancy test.
Results: Overall, we found a 6.3% prevalence of unrecognized pregnancy. Women with abdominal/pelvic complaints had a 13% prevalence; those with other complaints had a 2.5% prevalence. Two historical risk factors, the patient's suspicion that she might be pregnant and an abnormal last menstrual period, had a statistically significant correlation with unrecognized pregnancy. A third risk factor, the presence of abdominal/pelvic complaints, nearly achieved statistical significance. These risk factors detected all unrecognized pregnancies with a sensitivity of 100% and a specificity of 54%.
Conclusion: The prevalence of unrecognized pregnancy in our ED was 6.3%. Historical risk factors detected all of them.