Cumulative incidence of venous thromboembolism during pregnancy and puerperium: a hospital-based study.

Pregnancy is associated with an increased risk of venous thromboembolism. The rate of occurrence of this complication has not been reported from this area previously. The aim of this study was to establish the incidence of venous thromboembolism in pregnancy and puerperium by using objective diagnostic methods. From January 1986 to December 1998, 39,757 deliveries were registered at King Fahad Hospital, Al Baha, and 59 of these were referred to hematology services with a clinical suspicion of venous thromboembolism. The majority (86%) of these underwent objective diagnostic methods such as ascending venogram (AV) and color Doppler imaging (CDI) of the venous system for the diagnosis of deep venous thrombosis (DVT). Pulmonary scintigraphy was performed when available and echocardiography was included towards the end of the study. Fifty-nine patients with suspicion of pregnancy-associated venous thromboembolism (PAVTE) were studied. The diagnosis was confirmed in 50 patients, who received anticoagulation therapy. DVT was diagnosed in 35 (70%) cases and pulmonary embolism in 27 (54%) cases. The cumulative incidence of PAVTE was 1.25 cases per 1,000 deliveries (95% confidence interval = 0.89-1.16). One patient died during the study period (0.025 case per 1,000 deliveries). There was a predominance of venous thromboembolism during the postpartum period (66%), and DVT occurred more frequently in the left leg (77%). The risk of pregnancy-associated venous thromboembolism is low and a resulting death rare. Proximal or whole-limb DVT occurs more frequently and there is a predilection for the left leg. The majority of events occur in the postpartum period. A hypercoagulable state probably exists and needs further evaluation.