Level 1: Causes of Diarrhea in Pregnant Women Diarrhea in pregnant women may be caused by bacterial infection, food poisoning, drug side effects, etc. During pregnancy, diarrhea is common among pregnant women because the body\’s immunity declines and makes it susceptible to infection. Level 2: Does diarrhea in pregnant women have an impact on the fetus? Diarrhea in pregnant women has a certain impact on the fetus. if pregnant