Pregnancy Supplements: Omega-3

Omega-3 fats are found in foods including oily fish, and you may also see fish oil or algae-based omega-3 supplements marketed during pregnancy. If you are wondering whether you need to take one, current UK pregnancy guidance does not recommend a routine omega-3 supplement for everyone.

The NHS advises eating fish as part of a healthy pregnancy diet, with specific limits on certain types. It also warns against cod liver oil and other supplements containing vitamin A, also called retinol, during pregnancy.

If you do not eat fish, are considering an omega-3 supplement or are unsure which product is suitable, a midwife, GP, pharmacist or registered dietitian can help you look at your individual diet and circumstances.

What is omega-3?

Omega-3 is a family of polyunsaturated fats. Different forms include EPA and DHA, which are commonly associated with fish and fish oils, and ALA, which is found in some plant foods.

During pregnancy, discussions about omega-3 often focus on oily fish because the NHS includes fish within its healthy eating guidance. The NHS says oily fish is good for heart health and helps a baby’s nervous system develop.

That does not mean more is always better. Pregnancy guidance also places limits on oily fish because it can contain pollutants.

Do you need an omega-3 supplement during pregnancy?

Omega-3 is not among the routine pregnancy supplements specifically recommended by the NHS.

Current NHS guidance recommends folic acid and vitamin D during pregnancy, while a healthy, varied diet can provide most other vitamins and minerals. Other supplements may be advised in particular circumstances.

NICE also says fish oil or algal oil supplements should not be recommended solely for the purpose of preventing hypertensive disorders during pregnancy.

This does not mean an omega-3 supplement can never be appropriate. Diets and individual needs differ. If you are considering one, especially if you eat little or no fish, speak to a healthcare professional rather than assuming that every pregnancy supplement is necessary.

Getting omega-3 from fish during pregnancy

The NHS advises trying to eat two portions of fish a week during pregnancy, with one portion being oily fish such as salmon, sardines, trout, mackerel or herring.

There are limits to keep in mind. The NHS advises having no more than two portions of oily fish a week during pregnancy because oily fish can contain pollutants.

Tuna does not count as oily fish, but it has separate pregnancy limits because it contains more mercury than some other fish. NHS guidance says that if you are pregnant or trying for a baby, you should have no more than four cans of tuna a week or two tuna steaks a week.

The NHS also advises avoiding shark, swordfish and marlin during pregnancy.

These recommendations can feel like a lot to remember. If fish is part of your diet, following current NHS pregnancy food guidance is more useful than trying to maximise omega-3 intake on your own.

What if you do not eat fish?

Not everyone eats fish. You may be vegetarian or vegan, dislike fish, have an allergy, follow a particular cultural diet or simply choose not to include it.

Some plant foods contain the omega-3 fat ALA. Depending on your diet, you may also come across algae-based supplements that contain DHA or other omega-3 fats.

There is no need to assume that avoiding fish automatically means you need a supplement. The NHS advises people following vegetarian, vegan or special diets during pregnancy to pay attention to getting the nutrients they need, and professional advice can be useful if your diet is restricted.

A midwife, GP, pharmacist or registered dietitian can help you assess your diet and discuss whether any additional supplementation is appropriate.

Fish oil, omega-3 and cod liver oil are not the same thing

This distinction matters during pregnancy.

Some omega-3 supplements are made from fish body oil, while cod liver oil and other fish liver oils come from the liver of the fish. Fish liver oils can contain high levels of vitamin A in the form of retinol.

The NHS specifically advises against taking cod liver oil or supplements containing vitamin A during pregnancy because too much vitamin A can harm a baby’s development.

If you are looking at an omega-3 supplement, read the ingredients rather than assuming all fish-derived products are interchangeable. If the label is unclear, ask a pharmacist or another healthcare professional to check it with you.

How to choose an omega-3 supplement if one is recommended

If your healthcare professional recommends an omega-3 supplement, check exactly which type they mean.

Supplement labels can list different amounts of total fish oil, omega-3, DHA and EPA. These numbers are not necessarily the same thing, so comparing products based only on the largest number on the front of the packet can be misleading.

Also check whether the product contains vitamin A or retinol. Pregnancy guidance says to avoid supplements containing vitamin A, including cod liver oil.

If you already take a pregnancy multivitamin, show the label to your pharmacist, midwife or GP before adding another supplement. This helps them see what you are already taking and reduces the chance of unintentionally combining products containing the same nutrients.

Can omega-3 supplements prevent pregnancy complications?

Supplements are sometimes promoted with broad claims about pregnancy outcomes, but these claims should not replace clinical guidance.

NICE specifically advises that fish oils or algal oils should not be recommended solely to prevent hypertensive disorders during pregnancy.

Pregnancy complications have many possible risk factors and need individual assessment. If you have been told that you have a higher chance of developing a particular complication, discuss prevention and monitoring with your maternity team rather than relying on an over-the-counter supplement.

Food first does not have to mean a perfect diet

Pregnancy nutrition advice can easily become another source of pressure. Eating patterns can also change because of nausea, food aversions, appetite changes, finances, cultural preferences or dietary restrictions.

The aim is not to create a flawless pregnancy diet.

Current NHS guidance encourages a healthy, varied diet and provides clear limits for fish during pregnancy. If following those recommendations is difficult for you, mention it at an antenatal appointment. Your healthcare team can help you work out what is realistic and whether you need additional nutritional support.

When to get professional advice

Speak to your midwife, GP, pharmacist or registered dietitian if you are considering an omega-3 supplement and are unsure whether you need one, particularly if you follow a restricted diet, do not eat fish, take medicines or already use other supplements.

Ask a healthcare professional to check the product if you are uncertain whether an omega-3 supplement contains vitamin A or retinol. The NHS advises against cod liver oil and other supplements containing vitamin A during pregnancy.

If you have concerns about your nutrition during pregnancy, or you are struggling to eat a varied diet, raise this with your midwife or GP. They can consider your individual circumstances rather than relying on general supplement advice.

For urgent health concerns during pregnancy, contact your maternity unit or the appropriate healthcare service. NHS 111 can provide urgent medical advice if you are unsure where to seek help, and 999 should be used for a life-threatening emergency.