Aim of the study: To evaluate the influence of three common thrombophilic polymorphisms, factor V Leiden (FV), prothrombin G20210A (PT), and methylenetetrahydrofolate reductase (MTHFR) C677T mutations, on preterm birth of unknown cause.
Patients and methods: A single-centre case-control study of women with preterm infants < or =35 weeks of gestation, in whom obvious maternal, uterine, and fetal causes responsible for preterm birth were excluded (n = 35). The controls were 54 women with term infants hospitalised in the same ward.
Results: There were no significant differences between the groups of mothers in history of fetal loss, venous or familial thrombosis, or previous preterm birth. FV was found in 8.6% of the cases, PT in 5.7%, and MTHFR mutation (homozygous) in 4.8% compared with 5.4% (p=0.292, OR 1.594, CI95% 0.303-8.384), 7.4% (p=0.379, OR 0.758, CI95% 0.131-4.374), and 4.5% (p = 0.485, OR 1.050, CI95% 0.090-12.276), respectively, in the controls. Differences in the three thrombophilic polymorphisms in the two groups of infants were also not significant.
Conclusion: We could not demonstrate a distinct association between these thrombophilic polymorphisms and preterm birth.