A case series of Factor V Leiden mutation in pregnancy

Background. Pregnant patients with Factor V Leiden (FVL) mutation are at an increased risk of venous thromboembolic disease (VTED) and placental-mediated complications. Thromboprophylaxis with low-molecular-weight heparin (LMWH) can potentiallymitigate these risks. Objective. To describe the clinical course of a cohort of patients with FVL mutation with different underlying genotypes. Methods. The pregnancy outcomes, occurrence of VTED events and laboratory test results of pregnant women with FVL mutation managed at a quaternary medical centre over a period of 18 years in Johannesburg, South Africa, were analysed. Results. Over the period of analysis, 25 pregnant women with FVL mutation were referred to the haematology department for management. Ten patients (40%) had a family history, and 15 patients (60%) a personal history of VTED. The majority of provoked VTED events (90%) were secondary to combined oral contraceptive exposure. Previous pregnancy loss occurred in 4 (16%) patients, of whom 3 (75%) suffered recurrent losses. All women received prophylactic anti-Factor Xa (anti-FXa) dose-adjusted LMWH during anteand postnatal periods. All pregnancies resulted in live births with 1 VTED event recorded. Conclusion. Patients with FVL mutation show phenotypical heterogeneity in terms of pregnancy outcomes, VTED events and placentalmediated complications. Confounders contributing to the heterogeneity are not completely defined and deciding on appropriate treatment is not fully standardised but the live birth rate is encouraging.