The phenomenon of nausea when brushing teeth when pregnant is mostly seen in early pregnancy, mostly due to early pregnancy reaction, stimulation of the back wall of the throat when brushing teeth, or pharyngitis, as follows: 1, early pregnancy reaction: the early pregnancy hormone level in the body will change more obviously, pregnant women are prone to nausea, acid reflux and other early pregnancy reactions; 2, stimulation of the back wall of the throat: under normal circumstances, the back wall of the throat may be stimulated when brushing teeth, and for the early pregnancy reaction period 3. Pharyngitis: If a pregnant woman has pharyngitis, her throat may become dry, itchy and uncomfortable due to pharyngitis, or even have difficulty swallowing, causing nausea, which requires a visit to the hospital for treatment of pharyngitis under the guidance of a doctor. If nausea is caused by early pregnancy reaction, it is recommended that pregnant women should try not to use too large a toothbrush when brushing their teeth, take the right amount of toothpaste and brush gently to reduce the stimulation of the back wall of the throat, which will minimize the nausea caused. Generally speaking, after the third month of pregnancy, this situation will gradually ease as well as disappear, so pregnant women do not need to be too nervous about the situation of nausea, should be symptomatic treatment, to relieve, to maintain a good state of mind.