title: Recurrent venous thromboembolism after pregnancy-associated versus unprovoked thromboembolism.
abstract: It is not known whether women who develop venous thromboembolism (VTE) during pregnancy have a higher or lower incidence of recurrent VTE than women with unprovoked VTE. The aim of the study was to compare the risk of recurrent VTE among women with pregnancy-associated VTE to women with unprovoked VTE. Hospital discharge data identified women age 18-46 years old with pregnancy-associated or unprovoked index VTE between 1994 and 2005. Risk of recurrent VTE was compared between six and 60 months after the index event using both age-matched comparison of disease-free survival and proportional hazard modelling, adjusting for age and other risk factors. The Kaplan-Meier incidence of recurrent VTE in 1085 women with pregnancy-associated VTE was 5.8% versus 10.4% in 7625 women with unprovoked VTE (p = 0.02). Twelve of 34 (35%) recurrent events in the pregnancy-associated group occurred during a subsequent pregnancy compared with 29 of 331 (8.7%) events in the unprovoked group (p < 0.001). In the risk-adjusted multivariate model, women with pregnancy-associated VTE had a significantly lower risk of recurrent VTE (HR = 0.6, 95%CI = 0.4-0.9). Overall, the incidence of recurrent VTE during subsequent pregnancies was higher in the pregnancy group, 21 of 465 (4.5%), than in the unprovoked group, 37 of 1353 (2.7%, RR = 1.7, CI: 1.0-2.8). Compared to women with unprovoked VTE, women with pregnancy-associated VTE had a significantly lower long-term risk of recurrent VTE but a higher risk of recurrent VTE during a subsequent pregnancy. These findings should be considered when decisions are made about VTE prophylaxis in women with a history of pregnancy-associated VTE.
authors.affiliation: Department of Internal Medicine, UC Davis, Sacramento, CA 95817, USA. rhwhite@ucdavis.edu
authors.forename: Richard H
authors.initials: RH
authors.lastname: White
authors.forename: Wee-Shian
authors.initials: WS
authors.lastname: Chan
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Ginsberg
mesh_terms: D000328:Adult; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000453:epidemiology*