A

Low-dose unfractionated heparin (and LMWH) used for postoperative venous-thromboembolism prophylaxis is routinely given by subcutaneous injection (e.g., 5,000 U SC 2 h before surgery then every 8–12 h) rather than IV, IM, or inhalational routes, because SC dosing provides reliable anticoagulant levels without continuous infusion or bleeding risk from IM injections [Wessler, 1976, PMID 947059].