Diarrhea in the 5th month of pregnancy should be caused by indigestion, or enteritis. Diarrhea is not related to pregnancy, but if it is too severe during pregnancy, it can easily lead to miscarriage. You should determine the condition and treat it promptly, and try to keep warm and not eat cold food during this period. The first step is to determine whether the diarrhea is caused by a serious infection or by indigestion, which requires a routine stool test. If the diarrhea is caused by inflammatory infection, it should be treated with anti-inflammatory drugs, such as cephalosporin antibiotics, which will not affect the growth of the fetus. If the diarrhea is caused by indigestion, you can drink probiotics to treat it.