Mouth ulcers on the tongue during pregnancy may be due to the lack of vitamin B, oral mucosal injury, decreased immunity, etc., and need to apply lidocaine gel and other medications for the cause and pay attention to oral cleansing and so on. 1. Lack of vitamin B: pregnant women during pregnancy nutritional needs increase accordingly, inadequate nutritional intake can easily lead to vitamin B deficiency, and vitamin B is involved in a variety of substances in the body metabolism, enzymatic reactions and other processes, so there will be mouth ulcers, dermatitis and other diseases. Need to eat more vegetables, fruits, if necessary, the use of vitamin B complex tablets, rehabilitation of new liquid and other medications. 2. Oral mucous membrane injury: during pregnancy, you may eat hard and dry food such as potato chips, crispy bones, etc., or teeth accidentally biting injuries and so on, resulting in oral mucous membrane injury, secondary infection and cause oral ulcers. You can apply lidocaine gel, compound chlorhexidine gargle, watermelon cream powder, recombinant human epidermal growth factor gel and other medications. 3. Reduced immunity: Cold during pregnancy, lack of exercise, mental stress and other factors lead to decreased immunity, bacteria and other pathogens infections and cause mouth ulcers. Apply the above mentioned lidocaine gel, watermelon cream powder and other drugs for treatment. Mouth ulcers on the tongue during pregnancy may be related to a variety of factors, and it is recommended to seek medical advice to clarify the diagnosis. Pay attention to the use of medication under the guidance of a physician.