Pregnant woman is exposed to a high range of infections, not only bacterial, but also viral and parasitic. Many of these infections may produce severe diseases in the fetus and newborn child. The mother to child transmission can occur during pregnancy, during labor and in the postpartum period. This article summarizes some preventive strategies of proven efficacy against some of these infections: vaccination of the childbearing age women against rubella, varicella, hepatitis B and diphtheria-tetanus, and vaccination against influenza during pregnancy; screening tests of infections that have effective preventive measures (routine serologic test for HIV and syphilis, serologic test for hepatitis B in non-vaccinated women) and some strategies to prevent toxoplasmosis. The article also reviews with some detail the following infections when they occur during pregnancy: Group B b hemolytic Streptococcus, Listeria monocytogenes, Chlamydia trachomatis, genital herpes, chickenpox and B19 parvovirus. For each of these infections, epidemiological aspects are mentioned, as well as the timing and frequency of vertical transmission, risks for mother and child, therapy for mother infection and, mainly, preventive strategies for reducing vertical transmission