When diarrhea occurs in the third trimester of pregnancy, it usually does not affect the baby if the diarrhea is not severe. But if the diarrhea is more severe in the first trimester, it can affect the baby. This is because more severe diarrhea can easily lead to uterine contractions, causing the chance of miscarriage. If the diarrhea is severe, it will also easily lead to dehydration and acidosis, which will affect the health of the pregnant woman and indirectly affect the baby. Frequent diarrhea, will easily lead to malnutrition, nutrients can not be well absorbed, resulting in fetal malnutrition, slow growth, so when diarrhea needs to be treated according to the symptoms. If it is not serious, you can not take the way of treatment with drugs, usually try to pay attention to keep warm, light diet, adjust the daily life, diet can be improved. If the diarrhea is more serious, it is also recommended to take some drugs that have less effect on the fetus to alleviate the symptoms, you can drink bifidobacteria or montelukast for astringent antidiarrheal treatment.