Some symptoms common during pregnancy can be confused as cold symptoms; these include a runny or stuffy nose. BabyCenter refers to this condition as rhinitis of pregnancy; it can present itself as early as the second month of pregnancy, and it tends to worsen towards the end of pregnancy.
According to BabyCentre, during pregnancy the immune system changes its focus to protecting the development of the unborn baby. As a result, pregnant woman can be more susceptible to the germs that cause coughs, colds and flu. WhatToExpect.com explains that the immune system is lowered in order to keep the body from fighting off the unborn child, which is foreign to the body.