The review summarizes present knowledge on the possible negative influence of anti-infectious drugs on prenatal development and recommends therapy with minimal risk. It alerts on other factors that are to be considered, too. The risk need be evaluated with regard to the pharmaco-dynamic effect, which varies in different drugs. Some of them are inappropriate in 1st trimester, other only perinatally. Only time-tested drugs are appropriate for therapy in pregnancy or better, for all women of reproductive age. Treatment of infection is absolutely essential. Untreated disease represents a higher risk than appropriate treatment. Antibiotics should be selected according to the known sensitivity of the infectious agens and knowledge on their safety in pregnancy (penicillins and cephalosporins are the most appropriate). We should avoid drug combination, because adverse effects may be potentiated.

        Key words: pregnancy – infectious diseases – antibiotics.