1.

Study flow diagram

The primary search performed resulted 1698 studies, of which 1528 were excluded by reviewing the title and or removing duplicates, 104 were selected to be evaluated by the abstract, of these seven met the inclusion criteria. We excluded 97 studies by the primary selection because they lacked inclusion of patients undergoing abdominal or pelvic surgery, did not address thromboprophylaxis beyond day 14 after surgery, or were not clinical controlled trials. One trial were excluded as it was a double publication (Rasmussen 2003), and one because it was a review (Rasmussen 2003a). In addition, we found one trial by handsearching and only as an abstract presentation, and was reported as unpublished data (Jørgensen 2002). One study is actively recruiting patients (Zheng 2017), however, study methodology was not explicity outlined in the trial protocol.