Genetic hypofibrinolysis in complicated pregnancies

To assess the hypofibrinolytic 4G/4G mutation of the plasminogen activator inhibitor (PAI-1) gene as a possible factor contributing to severe preeclampsia, abruptio placentae, fetal growth restriction, and stillbirth.

We compared 94 women from a previous report who had obstetric complications to 95 controls with normal pregnancies matched for ethnic background and age. We collected blood and extracted DNA after delivery. All subjects had been tested for thrombophilic mutations factor V Leiden, C677T mutation in the methylenetetrahydrofolate reductase gene, and the G20210A mutation in the prothrombin gene. In the present study we tested for the hypofibrinolytic 4G/4G mutation in the PAI-1 gene.

Women who had obstetric complications were more likely than controls to be 4G/4G homozygotes, 32% (30 of 94) women versus 19% (18 of 95) controls, odds ratio (OR) and 95% confidence intervals (CI) 2.0 (1.02, 3.9). Mutations in the PAI-1 gene were independently associated with obstetric complications (OR 1.56, 95% CI 1.005, 2.43). Heterozygosity for the factor V Leiden mutation was more common in the 30 women who had PAI-1 4G/4G than in the 18 4G/4G controls (33% versus 0%, Fisher P =.008). Seventy-six percent of women had some form of thrombophilia or hypofibrinolysis compared with 37% of controls (Fisher P <.001).

Women with severe preeclampsia, abruptio placentae, fetal growth restriction, and stillbirth had increased incidence of the hypofibrinolytic 4G/4G mutation of the PAI-1 gene that is frequently associated with the thrombophilic factor V Leiden mutation, further predisposing them to thrombosis.