The structure of thrombophilia gene polymorphisms and disorders in the haemostasis are studied in 343 patients with obstetrical complications (main group) during the third trimester of the pregnancy. We revealed an important contribution of MTHFR gene allele variant 677T and of PA1-1 gene 4G/5G polymorphism to the development of preeclampsia. Thromboelastography is recommended for the diagnosis of gestation coagulopathy in patients with obstetrical complications with changes in the haemostatic tests. The urgency of correction of disorders of haemostasis is determined by the parameters of the clot formation (sensitivity 80%, specificity 82%). Correction of the disorders of haemostasis is indicated for pregnant patients with thrombophilia gene polymorphisms, who develop obstetrical disorders: low-molecular heparin and/or acetylsalicylic acid with folic acid and group B vitamins.