Diarrhea on the 35th day of pregnancy may be caused by physiological phenomena, acute gastroenteritis and other reasons. 1. Physiological phenomenon: after pregnancy, the body’s estrogen, progesterone and HCG (chorionic gonadotropin) levels increase, nausea, vomiting, acid reflux, fatigue and other early pregnancy reactions. Some pregnant women may also experience diarrhea and other symptoms, the general degree of diarrhea is not very serious, do not need special treatment, can be under the guidance of the doctor light diet. 2. Acute gastroenteritis: when eating unclean food or cold food after pregnancy, it will also lead to diarrhea, which may be accompanied by nausea, vomiting, fever and other symptoms. Combined with the history and clinical manifestations can be clearly diagnosed, need to be actively given rehydration therapy under the guidance of the doctor, and give montelukast and other medications. When diarrhea occurs on the 35th day of pregnancy, you need to go to the hospital to find out the cause and actively deal with it.