**6. Summary**

Research on maternal-fetal haemodynamics in preterm labor is currently focused mainly on the safety of the used tocolytics. The reduction of the use, and often the elimination of beta-agonists, undoubtedly increased the safety of the mother and the fetus. The above literature review proves that despite some influence of medications on maternal-fetal blood flow values, tocolysis does not significantly disturb haemodynamics. However, it is worthwhile to remember about safety rules during ultrasound examinations with the use of Doppler technique.
