Whether or not a pregnant woman with bad diarrhea has any effect on the fetus depends on the severity of the condition. If the pregnant woman does not have severe diarrhea and adverse reactions, it usually does not affect the fetus. If it lasts for a long time and is severe, it may lead to fetal dysplasia and miscarriage. 1. Maldevelopment: when a pregnant woman eats a bad stomach, the gastrointestinal tract will be disorganized, which will easily lead to intestinal cramps, and then there will be symptoms such as abdominal pain or fatigue. Subsequently, it will destroy the ability of the fetus to absorb nutrients, affecting the growth and development of the fetus, resulting in the phenomenon of fetal dysplasia. It is recommended that pregnant women should plan their diets according to their own situation to avoid the phenomenon of eating bad stomach. 2. Miscarriage: Pregnant women eat bad stomach, diarrhea increases, may also cause uterine contractions, if the time is prolonged may lead to miscarriage. Usually pay attention to clean diet, pay attention to keep warm, should go to the hospital for examination in time. During pregnancy, pay attention to diet, balanced nutrition, pay attention to keep warm. Pay attention to hygiene, regular maternity checkups, and if the situation is serious, immediately go to the hospital to consult a doctor.