I love eating fried bass fish. Why should I avoid it during pregnancy? Seafoods are usually rich in nutrients essential for the growth and development of your baby. But, there are certain foods that should be avoided. Bass is one of them. The reason being the fact that it is known to contain moderate to high levels of mercury that can lead to poisoning and brain damage in your baby. Apart from that, bass is also known to contain large amounts of other common pollutants like polychlorinated biphenyls that can harm the immune system of your growing foetus.