Fish or fish oil during pregnancy?

written by Meena Azzollini

pregnant woman holding fish oil supplements in hand


Dietary recommendations can be confusing during pregnancy. There is a list of food that pregnant women should avoid, including fish and another list which is highly recommended.

Consuming seafood during pregnancy is one of those highly debated topics – not recommended due to its mercury levels and subsequent effect on your baby’s health and development.

However, The Food and Drug Administration (FDA), the Environmental Protection Agency (EPA) and the 2015-2020 Dietary Guidelines for Americans recommend that pregnant women eat at least 8 ounces and up to 12 ounces (340 grams) of a variety of seafood lower in mercury a week. That amounts to two to three servings.

The risk of wheezing or asthma in children of the fish oil group was 16.9 per cent compared to 23.7 per cent in the olive oil group.

In Australia, Food Standards Australia New Zealand recommend consuming no more than one serve (100g cooked) per fortnight of shark/flake, marlin or broadbill/ swordfish, and no other fish that fortnight, or one serve (100g cooked) per week of orange roughy (deep sea perch) or catfish and no other fish that week.

This is because seafood – fish and shellfish is a great source of protein, iron and zinc – which are important for your baby’s growth and development. Some seafood also contains omega-3 fatty acids, including docosahexaenoic acid (DHA), which can promote your baby’s brain development.

Consuming fish during pregnancy has other benefits for your children. According to researchers from the University of South Florida in Tampa who published a review, pregnant women who consume fish protect their offspring from developing asthma.

But can the same effect be achieved by consuming fish oil supplements?

The review included two studies: Study A and Study B.

In Study A, 346 pregnant women in their third trimester took omega-3 fatty acids daily while 349 pregnant women took a placebo (olive oil). The women were also divided into three groups based on their blood levels of omega-3 fatty acids. The group with the lowest levels of omega-3 fatty acids benefitted the most from the supplementation.

The women and their offspring’s were followed for over 5 years to. Both the investigators and the women remained blinded till the child reached 3 years of age.

The risk of wheezing or asthma in children of the fish oil group was 16.9 per cent compared to 23.7 per cent in the olive oil group.

In Study B, pregnant women at 30 weeks were randomised to receive fish oil, no fish oil or a placebo. The fish oil group and the placebo group took omega-3 fatty acids daily. The “no oil” group was told of the trial and were allowed to consume fish or fish oil if they chose to.

The researchers found that the fish oil and “no oil “groups took less asthma medication as they aged to 24 years old, suggesting that both groups developed less asthma.

Omega-3 fatty acids are essential nutrients which cannot be synthesised by humans and therefore can only be derived from marine sources.

Whether pregnant women consume fish or fish oil supplements, they are just as likely to protect their children from developing asthma and by following the guidelines and recommendations in consuming low mercury fish, women can benefit their baby’s growth and development.

Source: The Journal of Allergy and Clinical Immunology: In Practice

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Meena Azzollini

Meena is passionate about holistic wellbeing, alternative healing, health and personal power and uses words to craft engaging feature articles to convey her knowledge and passion. She is a freelance writer and content creator from Adelaide, Australia, who draws inspiration from family, travel and her love for books and reading.

A yoga practitioner and a strong believer in positive thinking, Meena is also a mum to a very active young boy. In her spare time, she loves to read and whip up delicious meals. She also loves the smell of freshly made coffee and can’t ever resist a cheesecake. And she gets tickled pink by anything funny!