Perinatal infections contribute significantly to maternal, fetal, and neonatal morbidity and mortality, yet many are preventable. Infections can occur during pregnancy, at delivery, or postnatally, and can be transmitted via ascending routes or hematogenously. This chapter explores the impact of major perinatal infections such as toxoplasmosis, syphilis, rubella, CMV, and COVID-19, and highlights key preventive strategies including systematic screening, health education, and timely immunization. Special attention is given to vaccines safely administered during pregnancy, such as those for influenza, pertussis, and COVID-19, which offer critical protection during a vulnerable period.