Background: Pregnancy is the proved risk factor of venous thromboembolism (VTE). The peak of thrombotic events falls on the postnatal period, increasing their number at 5-15 times. A carriage of prothrombotic Leiden mutation during pregnancy is an additional risk factor of VTE and assumes carrying out thromboprophylaxis with low molecular weight heparins (LMWHs) in the antenatal and postnatal period. Thus, duration of therapy with LMWHs after cesarean delivery is a subject of a scientific discussions.
Aims: to study efficiency prolonged thromboprophylaxis after cesarean delivery in carriers of Leiden mutation, F5G1691A genotype, based on studying of a laboratory phenotype.
Methods: 
Design of research prolonged thromboprophylaxis after cesarean delivery in carriers of Leiden mutation, F5 G1691A genotypeA single-center randomized controlled study, the period of supervision was 2008-2020 years. The design of research is presented in figure 1.Efficiency of appointment nadroparin calcium was estimated on number of cases of VTE registered in the main group in relation to group of comparison.
Results: Statistical processing of the received results has shown the lack of episodes of VTE in the main group (RR=0.037; 95%CI 0.02-0.64; р=0.0235). 7 cases of VTE are registered in group of comparison: 4 supervision (16, 18, 21 and 37 days of the postnatal period) – thrombosis of deep veins of femur, one of which has become complicated with pulmonary embolism; 3 cases – thrombosis of deep veins of crus (19, 21 and 27 days). Using the declared method it is necessary to treat 8 patients (NNT=7.7; 95%CI: 5.05–16.76; p=0.0223) to avoid 1 case of development of VTE in patients with Leiden mutation, F5G1691A genotype.
Conclusions: at carriage cases of Leiden mutation, F5G1691A genotype, with the shown laboratory phenotype in the form of APC-R ≤0,49 on NR, after cesarean delivery it is reasonably to use prolonged thromboprophylaxis with LMWHs up to 42 days in prophilactic doses.
To cite this abstract in AMA style:
Nikolaeva M, Shchekleina K. Duration of Thromboprophylaxis with Low Molecular Weight Heparins after Cesarean Delivery in Carriers of Leiden Mutation, F5g1691a Genotype [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/duration-of-thromboprophylaxis-with-low-molecular-weight-heparins-after-cesarean-delivery-in-carriers-of-leiden-mutation-f5g1691a-genotype/. Accessed September 24, 2021.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/duration-of-thromboprophylaxis-with-low-molecular-weight-heparins-after-cesarean-delivery-in-carriers-of-leiden-mutation-f5g1691a-genotype/