The Frequency of Venous Thromboembolism in Women with F V Leiden in Heterozygous Form from the East Bohemia Region in Association with Pregnancy and Puerperium.
Authors: Dulicek Petr , Zak Pavel , Maly Jaroslav , Pecka Miroslav , Maisnar Vladimir , Beranek Martin 
Published: October 2019

Introduction: Venous thromboembolism (VTE) is an important cause of maternal morbidity and mortality throughout the developed world. VTE is multifactorial disease. The incidence of VTE increases 2–4 fold in pregnancy and is higher after caeserean section than after vaginal delivery. Individuals with F V Leiden mutation have 3–7 fold higher risk of VTE. The risk of VTE in women with heterozygous form of F V Leiden during pregnancy is considered to be low ( less than 3%), but some other data show higher risk ( almost 10%) according design of the studies.

The aim of study: The assessment of the frequency of VTE in women with F V Leiden in heterozygous form in association with pregnancy and puerperium from the East Bohemia region and the comparison of our results with similar studies. Our results and available data should enable us to make an idea about the proper strategy of thromboprophylaxis in these settings. The frequency of F V Leiden is 2% in our region. It is retrospective case control study.

Materials and methods: The assessment of the frequency of VTE in the group of 224 women with F V Leiden in association with 460 pregnancies. This group consists from women after VTE with F V Leiden in heterozygous form ( without other inherited thrombophilia and APS) and from asymptomatic family members with F V Leiden ( 104 index cases, 120 family members). The frequency of VTE was compared with the frequency of VTE in the control group of 201 women without F V Leiden in association with 422 pregnancies. This control group consists from asymptomatic family members of women from the first group without detection of F V Leiden and from women examined in our department during the assessment of the frequency of F V Leiden in our population, when F V Leiden was not diagnosed ( 101 asymptomatic family members, 100 healthy women). Coagulation work up was done in the period of 1996 – 2003. All women had at least one pregnant and all pregnancies were without thromboprophylaxis. The presence of F V Leiden mutation was determined after DNA extraction, polymerase chain reaction ( PCR) and Mnll restriction analyses. VTE ( DVT and PE) was objectively determined in all cases.

Results: In the investigated group VTE occurred 44x during pregnancy and puerperium. In l7 cases VTE was manifested in pregnancy ( 1x in I. trimester, 2x in II. trimester, 14x in III. trimester), in 27 women VTE occurred in puerperium and always within the first 10 days after delivery. Proximal venous thrombosis was diagnosed in 34 cases, in 5 cases was complicated by pulmonary embolism. In 10 women thrombosis was distal. The frequency of VTE was 9,6%. The frequency of VTE in the control group was 0,24%. The results were statistically assessed by Fisher’s exact test in programme NCSS 2004. The frequency of VTE in the cohort of women with F V Leiden reached statistical significance in comparison with the control group.

Conclusion: Pregnancy and puerperium have been found the risk factors for VTE in investigated group. Our data can be affected by high number of index cases in the first group. In spite of this result we do not recommend pharmacological thromboprophylaxis to all women and thromboprophylaxis is considered on individual basis after the assessment of all other risk factors of VTE.