At 21 weeks of pregnancy, if the diarrhea is not serious, pay attention to keep warm. Use a hot water bag to apply warm compresses, eat a light diet, drink some millet porridge in moderation, do not eat too greasy food, do not eat spicy and stimulating food. If the diarrhea is serious, you can drink montelukast for treatment. If you feel that your baby is moving less often, you need to do an ultrasound to see if there is intrauterine ischemia and hypoxia, if it is determined that the baby has intrauterine ischemia and hypoxia, then you should promptly inhale oxygen treatment.