Yeast infection is a common type of vaginal infection that occurs really often in women who are pregnant. These infections are caused by microscopic fungi in the Candida family. They are normally found in the vaginas of nearly one third of women. It only becomes a problem when it grows so fast that it overwhelms other competing microorganisms that are normally found in the vagina. Increased estrogen level during pregnancy causes your vagina to produce more glycogen. This makes it even easier for yeast to grow in the vagina. The most common symptoms of yeast infection are odorless and white vaginal discharge, itchiness, irritation and redness in your vagina and labia, pain during sex and burning sensation during urination. A yeast infection won't hurt or affect your baby. However, if you have an infection when you go into labor, there is a chance that your newborn will contract it as he passes through the birth canal. A yeast infection in a newborn is called thrush. It is recognizable by the white patches in a baby's mouth and it is not serious and is easily treated.