What precautions should pregnant women take before eating tuna? Tuna is a saltwater fish and is widely eaten. It is a good source of nutrients, vitamins, and minerals. For instance, the vitamin D and omega-3 fatty acids in tuna can aid in the development of the baby’s brain, eye, and nerves. Likewise, the abundance of vitamin A and B12 prevent anemia in the mother and neural tube defects in the baby. However, there is still no concrete classifaction of tuna, that means it doesn’t come in the safe or unsafe list of fish during pregnancy. The safety of having tuna also depends on the type of tuna as each type has different safety levels depending on its mercury level. Since it contains higher than normal mercury levels, pregnant women should either avoid eating it completely, or eat the recommended amount of light and canned tuna. Excess intake may lead to accumulation of mercury in the mother’s system and thereby cause brain and nervous damage and lead to physical deformities in the baby. Hence, it is best to minimize tuna consumption during pregnancy.