What are the benefits of including some type of fish or shellfish in ones pregnancy diet and why must other types of fish and shellfish be avoided during pregnancy

you shouldn't eat any shark, swordfish or marlin. You should also limit your tuna intake to no more than two 140g tuna steaks or four 140g cans of tuna per week. This is because these fish are slow growing and may contain more mercury than other types of fish, which can affect your baby's developing nervous system