Submitted January 17, 2002
Accepted March 7, 2002
Temporary increase in the risk of recurrence during pregnancy in women with a history of venous thromboembolism
Ingrid Pabinger*, Helga Grafenhofer, Paul A Kyrle, Peter Quehenberger, Christine Mannhalter, Klaus Lechner, and Alexandra Kaider
Department of Internal Medicine I, Division of Haematology and Blood Coagulation, Vienna University Hospital, Vienna, Austria
Department of Laboratory Medicine, Vienna University Hospital, Vienna, Austria
Department of Medical Computer Sciences, Vienna University Hospital, Vienna, Austria
* Corresponding author; email: ingrid.pabinger{at}akh-wien.ac.at.
There is strong evidence that the incidence of venous thromboembolism (VTE) is increased during pregnancy. However, it is not known whether and to which extent pregnancy influences the risk of recurrent VTE in women with previous thrombosis. To investigate, whether pregnancy temporarily increases the risk of recurrent thrombosis, we retrospectively evaluated the recurrence rate in 109 women who had at least one pregnancy after an episode of VTE by comparing the time-period during pregnancy to the non-pregnant period. Forty-three women had a first recurrence during a total observation time of 1014 years. Eight events (73 observation years) occurred during, 35 (941 observation years) outside pregnancy. Recurrence rate per 100 patient-years was 10.9 during and 3.7 outside pregnancy. The relative risk during pregnancy was 3.5 (95% confidence interval 1.6 - 7.8, p = 0.002). Our data suggest that pregnancy leads to a temporary increase in the risk of recurrent thrombotic events.
