What foods to avoid when pregnant? Try to avoid the intake of the raw meat or eggs. The reason is that they may be contaminated with the bacteria named Listeria. The bacteria have the ability to poison the blood and thus causes harm to the immature baby growing inside the expecting mom. Also, undercooked foods come into the list of food to avoid during pregnancy. Undercooked foods must also be refrained from as they are may cause miscarriage. The chances of stillbirth are also high. Eating fish during pregnancy is good but if it is high in mercury it needs to be avoided.