Infections in pregnancy still pose a challenge to public health, especially in less developed countries. They may occur in intrauterine life, and are classified as congenital, or during childbirth and immediate postpartum when they are known as perinatal infections. Infections that occur during pregnancy trigger mechanisms that may culminate in preterm labor, fetal malformations, and fetal and neonatal death. Recognition of signs and symptoms and early diagnosis are the key to reducing the damage that these infections can cause in the mother and the fetus. In this chapter, we will discuss the main infections, risks for maternal and fetal health and strategies that can be used to minimize harm.