Inherited thrombophilias and adverse pregnancy outcomes: A case-control study in an Australian population

Objective. The primary aim of this study was to examine the association between inherited thrombophilias and adverse pregnancy outcomes in an Australian population. Design. Case-control study. Setting. Two Australian tertiary level maternity hospitals. Population. One hundred and fifteen cases with adverse pregnancy outcomes, comprising severe pre-eclampsia (n=45), fetal growth restriction (n=44), placental abruption (n=16) or stillbirth (n=10), and 115 controls matched for ethnicity, parity and maternal age. Methods. Genotyping for factor V Leiden, prothrombin gene mutation, methylenetetrahydrofolate reductase 677 and 1298 and thrombomodulin polymorphism was performed using Taqman assays in an ABI prism 7700 Sequencer. Pregnancy outcome data were extracted from the medical record at the time of recruitment. Main Outcome Measures. Prevalence of inherited thrombophilias in women with adverse pregnancy outcomes and matched control women. Results. There were no differences in baseline characteristics between cases and control women, apart from duration of gestation and neonatal birthweight. Overall, there was no significant difference in the prevalence of these inherited thrombophilia polymorphisms between cases and control women. Heterozygosity for the factor V Leiden mutation, however, was significantly associated with an increased risk of both stillbirth (odds ratio 9.33, 95% confidence interval 1.36-64.15, p=0.02) and placental abruption (odds ratio 8.62, 95% confidence interval 1.57-47.17, p=0.01). Conclusions. Overall, this study does not support a significant association between inherited thrombophilia polymorphisms and adverse pregnancy outcomes. Our two statistically significant findings should be interpreted with caution given the small number of patients in these subgroups (10 stillbirths and 16 placental abruption cases) and the wide confidence intervals.