During intrauterine life, the fetus can be exposed to a series of substances ingested by the mother, some of which are necessary for her health but detrimental to fetus. The noxious effects of such exposure could present immediately after exposure in the fetus or be manifested at the time of delivery and sometimes weeks after birth. The passage of drugs or nutrients across the placenta depends on some physicochemicals that have the ability to cross the placenta barrier, and thus get in contact with the fetus and produce harmful effects. Considering the physicochemical properties of the substances, the possibility of such compounds to cross the placenta barrier and thence to the fetus can be predicted. Equally, it is important to consider the characteristics of the newborn as an immature being, different from adults, when carrying out pharmacokinetic and pharmacodynamic processes. Based on the latter, it is important to know the behavior or characteristics of the fetus and the newborn in the face of drug management and above all consider the advantages and disadvantages of the use of such drugs for the care of a being yet in development, as is described in this work.