Even though it is true that all seafoods contain some amount of mercury, not all of them contain the same levels of this toxin. Fishes with low levels of mercury are considered safe to eat during pregnancy. But, burbot is among one of the many fishes that have high levels of mercury. This can be harmful to your unborn baby. According to a study conducted by the Harvard School of Public Health, mercury can lead to irrepairable brain damage to the foetus. Hence, you should avoid having burbot during pregnancy.