Objective: To evaluate whether trimester specific d-dimer levels and brain natriuretic protein (BNP), along with the modified Wells score (MWS), is a useful risk stratification tool to exclude pregnant women at low-risk of pulmonary embolism (PE) from diagnostic imaging with radiation exposure.

To account for all women meeting the study eligibility criteria, this study utilized a combined prospective and retrospective arm. Pregnant women who underwent diagnostic imaging to evaluate for suspected PE at our institution were prospectively enrolled from February 2014 to August 2015. Both d-dimer and BNP serum levels were drawn, and a MWS was assigned. All pregnant women diagnosed with a PE that underwent diagnostic imaging and had a d-dimer level drawn from January 2009 to June 2014 were retrospectively enrolled. Patient electronic records were used to apply the MWS and analyze their risk.

Inclusion criteria:

• adult pregnant women >= 18 years old
• d-dimer obtained and if the patient was pregnant at the time of PE diagnosis
• patient presented to the Emergency Department or Labor and Delivery unit
• patient presented with signs and symptoms suspicious for PE

Exclusion criteria:

• non-pregnant patients
• patients < 18 years old

pregnant women who presented to the Emergency Department or Labor and Delivery unit with signs and symptoms suspicious for PE