Background: Factor (F)V Leiden and the prothrombin 20210A mutation (PTm) are associated with the occurrence of obstetric complications, including pregnancy-related venous thromboembolism (VTE). It is not known whether family members of women with FV Leiden or PTm and previous obstetric complications have a higher risk of VTE or adverse obstetric outcomes.
Methods: A retrospective family study including 563 relatives of 177 women with previous adverse outcomes carrying FV Leiden or PTm, referred between April 1993 and June 2010. A history of obstetric complications and VTE was obtained. Prevalence of VTE and obstetric complications in relatives with and without inherited thrombophilias was compared. Adjusted odd ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression models that controlled for predictors (age, FV Leiden and PTm).
Results: Relatives carrying FV Leiden had a significant and independent risk for obstetric complications (OR: 1.98, 95% CI 1.03-3.83); this risk was not observed in the presence of PTm (OR: 1.03, 95% CI 0.46-2.32). The presence of FV Leiden or PTm in heterozygosis was significantly and independently associated with the occurrence of VTE (OR: 5.2, 95% CI: 1.70-15.91). Severe thrombophilias were strong risk factors for VTE (OR: 23.2, 95% CI: 6.0-89.85). Male gender was a significant and independent risk factor for VTE (OR: 3.49, 95% CI: 1.51-8.05). The risk did not change when relatives of women with a previous pregnancy-related VTE were excluded (OR: 3.49, 95% CI: 1.51-8.05).
Conclusions: Knowledge of thrombophilia status may help to better define the obstetric and thromboembolic risks in asymptomatic family members of women who suffered from obstetric complications.
© 2011 International Society on Thrombosis and Haemostasis.