The main reasons for bad breath in pregnancy are due to oral problems, changes in hormone levels, and the effects of morning sickness. When pregnant, pregnant women may pay attention to diet and their own health problems, will regularly go to maternity check-ups, but did not pay attention to the oral problems, because during pregnancy will eat irregularly, oral problems will be ignored, this time there will be oral problems, resulting in bad breath of pregnant women, this situation can be solved by paying attention to oral hygiene problems. During pregnancy, with the development of the baby, the level of hormones will increase significantly, and this time will affect the chemical composition of saliva, which will lead to bad breath. This condition will disappear after delivery, mainly due to hormonal changes, and will disappear when the hormones return to normal levels. Morning sickness is also a cause of oral disease, which is not related to the vomit, but mainly the acid-base level of the vomit will affect the balance of bacteria in the mouth. This time the balance is disturbed and can lead to bad breath problems. Bad breath in pregnancy is a common occurrence, mainly caused by changes in the composition of saliva, and these symptoms will disappear after delivery, so there is no need to worry.