Impact of common thrombophilias and JAK2 V617F on pregnancy outcomes in unselected Italian women.

BACKGROUND: Although an association between thrombophilias and adverse pregnancy outcome has been shown, the influence of the most common inherited thrombophilias and the somatic mutation JAK2 V617F in determining an adverse outcome is questioned. OBJECTIVES: We examined the contribution of the factor V Leiden (FVL), the prothrombin G20210A (PTm) and the somatic JAK2 V617F mutations to adverse pregnancy outcome in an unselected cohort of pregnant women. PATIENTS/METHODS: During the study period, 5345 pregnant women were admitted to the 14 hospitals of the five provinces of the Campania region (Italy). Of these, 3097 samples were investigated and obstetric history collected. The presence of the FVL, PTm, and JAK2 V617F mutation was prospectively determined by polymerase chain reaction followed by TaqMan SNP genotyping assays. RESULTS AND CONCLUSIONS: We identified 119 (3.8%) women that carried FVL and 138 (4.4%) with the PTm. Only 4 (0.1%) women carried both mutations. Only one woman tested positive for the JAK2 V617F somatic mutation. The prevalence of a previous history of an adverse pregnancy outcome was similar in women with common thrombophilias as compared to those without. In the current pregnancy, there was no association of any of the genetic markers considered with any of the adverse outcomes investigated. Carriership of FVL or PTm showed a positive trend with delivery of a small for gestational age newborn (OR: 1.5, 95% CI: 0.9-2.5). Pregnancy outcomes in asymptomatic women with inherited thrombophilias are often uneventful. Therefore, in women at low-risk of an adverse pregnancy, neither screening for common thrombophilias nor administration of routine thromboprophylaxis are warranted.