The article deals with using peculiarities of antimicrobial drugs for the systemic application in pharmacotherapy of pregnant women. They are associated primarily with the physiological and immunological changes in the body of a pregnant woman, which result in the particular pharmacokinetics of drugs. It is shown that prescribing the treatment for infectious diseases in pregnant women should be based on a thorough analysis of possible side effects and undesirable effects, especially on the fetus. It has been established that the most acceptable to the pharma-cotherapy of pregnant women are antimicrobial drugs of category B and C according to the safety FDA classifica-tion, registered in the State Register of drugs of the Republic of Belarus.