What are the benefits of including some types of fish and shellfish in one’s pregnancy diet, and why must other types of fish and shellfish be avoided during pregnancy?

Some women worry that eating seafood during pregnancy can be harmful; in most cases, this isn’t true. Seafood is actually very good for your baby – there are just a few kinds of fish that should be limited or avoided.

The NHS recommend that pregnant and breastfeeding women should avoid eating more than two portions of oily fish per week, though eating seafood up to these limits is very good for your baby.

Studies have shown that children whose mothers ate fish during pregnancy had a 'higher intelligence quotient' than those whose mothers didn't eat fish. However, there a few species of seafood which should be limited or avoided during pregnancy.

When you're pregnant (or trying), 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.  The instruction is just for pregnant women - Adults can eat 1 portion of these, visit the NHS website for information.

Pregnant women should also avoid eating more than two portions of oily fish per week, such as salmon, trout and mackerel. This is because these fish can contain small amounts of pollutants.

Yes to all three. Shellfish is absolutely fine as long as care has been taken to make sure it is cooked through, and the raw fish used to make sushi simply needs to be thoroughly frozen for at least 24 hours beforehand.

Smoked fish is cured and not 'raw', which also means it is safe to eat while pregnant. Some countries advise against eating smoked fish when pregnant because of the risk of listeria, but the risk of this in the UK is very low.

Yes! In the UK, restaurants must comply with strict hygiene and cooking standards which ensure that food is well cooked or cured, or frozen for at least 24 hours, in the case of sushi. If you want extra reassurance, you can always inform the staff that you would like special care to be taken that the seafood is cooked through.

To read more about eating seafood during pregnancy, head to the Fish is the Dish page on Becoming a Mum. The NHS have also prepared a guide on foods to avoid for pregnant women.