Level 1: Causes of Diarrhea in Pregnant Women Diarrhea in pregnant women is a common phenomenon, and its causes may be many. First of all, pregnant women have undergone great changes in their bodies, resulting in weakened gastrointestinal functions and prone to indigestion and diarrhea. Secondly, pregnant women may be infected with pathogens such as bacteria, viruses or parasites, which can also cause diarrhea. In addition, pregnant women who do not pay attention to dietary hygiene or eat expired and spoiled food may also cause diarrhea. Level 2: Symptoms of diarrhea in pregnant women. The main symptoms of diarrhea in pregnant women are diarrhea, abdominal pain, nausea, and vomiting.