The research goal was to study the influence of extremely high temperatures on the hemostasis indices in patients with uncomplicated pregnancies with the concomitant limitation of liquid intake. The research results of hemostasis of pregnant women being hospitalized during the period of spring and summer in 2010 have been analyzed. The differences in the level of hypercoagulation changes of hemostasis in summer and spring have been found to be insignificant. In the platelet link hemostasis in summer of 2010, as compared to the spring, the increase of platelet aggregation and amount has been observed, with the exception of the third trimester, which is marked by the decrease of platelet amount. Hot seasons and liquid intake limitations make additional demands on hemostasis adaptive capacity, increasing the risk of thrombohemorrhagic complications