[Teratologic effects of benzodiazepines].

Benzodiazepines are drugs that belong to the group of minor tranquilizers. They derive from the 1-4, benzodiazepine common nucleus that was obtained by chemical synthesis and act upon the GABA receptors increasing their affinity, thus providing them with their tranquilizing, miorelaxing, and anticonvulsant properties. Due to these characteristics they have been used in a wide variety of disorders accompanied by anxiety, hyperexitability, convulsions, and muscular hypertony, as well as during pregnancy and labor. Before using them in pregnant women, the physician should consider the conditions of the product "in uterus" since, according to experimental evidences, benzodiazepines could interfere with embryonary development, mainly with those involved in central nervous system mechanisms causing tissular alterations, retardment in cellular differentiation, and behavioral disturbances. Besides, since the fetus has lower excretion rate than that of the mother, drug concentrations are greater than the therapeutic ones and fetal tolerance to the compound, administered during the last trimester, is reduced, originating abstinence or intoxication syndromes in the newborn. It is concluded that more research is needed to evaluate all the aftereffects caused by using these drugs during pregnancy.