Background: Women with venous thromboembolism (VTE), thrombophilias or mechanical heart valves may require anticoagulation during pregnancy and postpartum. The incidence of postpartum hemorrhage (PPH) in the literature is 2.9-6%, but the rate while on anticoagulation is not well documented.Aims: To determine the incidence of haemorrhagic complications associated with the use of peripartum anticoagulation, and the types and risk factors for haemorrhagic complications.Methods: A retrospective chart review was conducted on women who delivered at an academic teaching hospital and received peripartum anticoagulation between January 2000 and August 2009. Women with known bleeding disorders were excluded.Results: In total, 195 cases were identified with mean age 31.3 years and gestational age of 37.7 weeks. Of these, 49% had a history of VTE, 21% had active VTE in the index pregnancy, and 63% had vaginal delivery. Types of anticoagulation used antepartum were unfractionated heparin (UFH) (43%) and low molecular weight heparin (LMWH) (36%), with 26% receiving therapeutic doses. The rate of haemorrhagic complications was 12.8%, with majority being PPH (80%). Sixty percent of the PPH occurred before reintroduction of anticoagulation postpartum. Use of therapeutic UFH antepartum was associated with increased risk of haemorrhagic complications compared to LMWH (OR 3.08, p ¼ 0.183). Conclusion:The rate of haemorrhagic complications is higher in women on peripartum anticoagulation compared with published incidence in unselected obstetric populations; however, this rate is similar to our institution's reported rates. Our findings inform clinicians about competing risks of thrombotic and haemorrhagic complications in this population.