Omega-3: What It Is and Why It Matters During Our Child Bearing Years

Omega-3 fatty acids are essential polyunsaturated fats that our bodies cannot make on its own, meaning we need to get them from our diet.

The three main types of omega-3 fatty acids are:

• DHA (docosahexaenoic acid) – important for brain and eye development. DHA is abundant in oily fish.

• EPA (eicosapentaenoic acid) – supports heart health and reduces inflammation. Also primarily found in oily fish.

• ALA (alpha-linolenic acid) – a plant-based omega-3 that can be converted into DHA and EPA (though this process is quite inefficient- more on this below). Found in some seeds and nuts.

European Food Safety Authority (EFSA) recommends:

• 250 mg of DHA + EPA per day adequate intake for adults.

• Pregnancy and breastfeeding: an additional 100–200 mg DHA per day is advised to support fetal and infant development.

What more personalised advise on how much omega 3 to have? Why not book in for a free chat?

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Omega-3 and Trying to Conceive (TTC)

When TTC omega 3 is actually important for both partners! These fatty acids support reproductive health in several areas.

Improved egg quality: DHA is a major component of cells, including egg cell membranes. Studies suggest that women with higher omega-3 levels have better egg quality markers during IVF treatment.

Enhanced Ovarian Function: EPA's anti-inflammatory properties may help reduce inflammation in the reproductive organs, potentially improving ovarian function, and hormone balance. Omega-3s may also enhance blood flow to the ovaries, ensuring it receives the oxygen and nutrients needed for healthy egg development.

Regulated Menstrual Cycles: Omega-3 fatty acids can help regulate hormone production, which can influence menstrual cycle regularity and ovulation.

Male Fertility Benefits: For men, omega-3s support sperm quality, motility, and morphology. DHA is particularly concentrated in sperm membranes.

Key Take Aways - Higher omega-3 intake has been associated with:

• Increased probability of conception

• Better embryo quality during IVF

• Improved time to pregnancy

  
  

  Aim for 1-2 portions of oily fish a week or at least 250–500 mg of DHA+EPA per day, (with some studies using up to 1,000 mg DHA safely)

Omega-3 During Pregnancy

Pregnancy increases your need for omega-3 fatty acids, particularly DHA, which is essential for your baby's brain and eye development.

Fetal Brain Development: DHA builds up rapidly in your baby’s brain during the third trimester. Consuming enough DHA supports your baby’s brain growth, eyesight, and nervous system development.

Reduced Risk of Preterm Birth: Some studies have shown that omega-3 supplementation, particularly DHA, can reduce the risk of preterm birth particularly those born less than 34 weeks gestation.

Prevention of Small for Gestational Age (SGA): Research indicates that omega-3 supplementation may reduce the risk of having a small for gestational age baby. SGA baby’s are more prone to requiring medical support when born for breathing, feeding and temperature regulation.

Maternal Mental Health: Omega 3 has also been associated with reducing the risk of prenatal and postnatal depression.

Reduced Risk of Allergies: Some studies suggest that maternal omega-3 intake may reduce the risk of allergies and asthma in children.

As a Dietitian who works on the neonatal unit and supports families with preterm babies and those needing medical invention, I feel very passionate about doing what we can to prevent preterm birth and ensuring adequate Omega 3 can be such a simple win.

Aim for 2 portions of oily fish a week or at least 250–500 mg of DHA+EPA per day. Women with higher risk factors may wish to consider taking a higher dose with studies looking at 1000mg a day for preventing pre term birth.

Omega-3 and Breastfeeding

Whilst many people may spout “It doesn’t matter what you eat when you are breastfeeding” there are actually several nutrients in breastmilk which are influenced by maternal diet. Nonetheless regardless of your diet breastmilk will always be the definition of personalised unique nutrition! Your body will always try and prioritise making high quality milk for your baby but this can be at the detriment of mums on health too.

Some fun nutrition breastmilk facts:

• Breastmilk for boys is more energy dense

• Your breastmilk will become more “watery” if the weather is hot to keep your baby hydrated

• Breastmilk responses to provide antibodies if your baby is unwell

• Breastmilk can change colour and flavour depending on what your eat

  
  
  
  

Back to omega 3…

When a breastfeeding mother consumes omega-3 rich foods or supplements, the fatty acid composition of her breast milk changes within hours to days. This means that maintaining adequate omega-3 intake throughout breastfeeding is essential for providing optimal nutrition to your baby.

Continued Brain Development: Your baby's brain continues developing rapidly during the first few years of life. The DHA in breast milk supports this ongoing development, particularly in areas related to learning, memory, and visual processing.

Immune System Support: EPA and DHA in breast milk help support your baby's developing immune system and may reduce the risk of infections and allergies.

Omega-3 Sources

Oily fish

• Wild atlantic salmon

• Farmed Atlantic salmon

• Sardines

• Mackerel

• Anchovies

• Trout

Note that omega 3 content of fish can vary depending on what the wild or farmed fish eat.

Plant Based

• Flaxseeds

• Chia seeds

• Walnuts

• Hemp seeds

• Rapeseed oil

The ALA Conversion

While plant sources provide ALA, it's important to understand that ALA must be converted to EPA and DHA in the body. Unfortunately, this conversion process is highly inefficient. Research shows that only about 0.2-8% of ALA is converted to EPA, and even less (0.05-4%) is converted to DHA.

This low conversion rate means that while plant sources are beneficial, they cannot completely replace the need for direct sources of EPA and DHA, particularly during pregnancy and breastfeeding when requirements are highest.

Mercury Concerns and Safe Fish Consumption

While oily fish are excellent sources of omega-3s, some varieties can contain mercury, which is particularly concerning during pregnancy and breastfeeding.

Fish to Limit or Avoid:

• Shark, swordfish, marlin - High mercury

• King mackerel - High mercury

• Tuna - Moderate mercury (limit to 2 portions per week or 4 cans)

Safe Consumption Guidelines:

• Pregnant and breastfeeding women should consume 2 portions of low-mercury, oily fish per week

• Vary your fish choices to minimise exposure to any single contaminant

• Consider omega-3 supplements from reputable brands that test for heavy metals

 For more food safety advice check out my food safety guide

Pregnancy Food Safety

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What If You Don’t Eat Fish or just can't tolerate it in pregnancy?

If you’re vegetarian, vegan or just don’t like fish you may wish to consider an omega 3 supplement. You can also find algae-based omega-3 supplement which are vegan. (These provide a direct source of DHA and EPA without relying on conversion from ALA)

When choosing a supplement consider:

• Look for third-party testing for purity and potency

• Choose supplements that provide both EPA and DHA and the serving

• Check for sustainability certifications

• Ensure the supplement is free from harmful contaminants

Here are some options

Please note that some of these links are affiliate links which may mean I earn a commission at no additional cost to you. These are clearly marked with * Please always discuss with your own health care providers before taking supplements.

Brand	Key Features
Nothing Fishy	2 capsules 400mg DHA 3rd party tested Vegan - algae derived Recyclable packaging materials
Wild Nutrition*	4 capsules provide 400mg DHA Derived from Pollock Third party tested
Inessa	1 capsule 360mg DHA Derived from anchovies
Inner Vitality*	1 x 5ml teaspoon 550mg DHA 3rd party tested Lemon flavour (no fishy taste) Tested for no heavy metals or pollutants Derived from wild sardine, herring & anchovy
Proceive*	2 capsules 440mg DHA Tested for no heavy metals Derived from sardines 3rd party tested
Bare Biology*	2 capsule 440mg DHA 3rd party tested Derived from mackerel & sardines Tested for heavy metals, mercury

Final Thoughts

Omega-3s are one of the most essential yet under consumed nutrients in women in the UK during their reproductive years (NDNS 2025). From supporting fertility and egg quality to fetal development and enriching breast milk, these essential fats play crucial roles throughout the journey of motherhood.

Whether through increasing consumption of low mercury oily fish or choosing high-quality supplements, ensuring adequate omega-3 intake can be one of the most impactful nutritional decisions you can make for your health and your baby's development.

Remember that individual needs may vary, and it's always best to consult with your healthcare provider about your specific omega-3 requirements.

For personalised support with diet and supplements during this unique time book a free video discovery call below!

Free Video Discovery Call

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 References

1. Hammiche F, Vujkovic M, Wijburg W, et al. Increased preconception omega-3 polyunsaturated fatty acid intake improves embryo morphology. Am J Clin Nutr. 2011;94(6):1522–1529. https://doi.org/10.3945/ajcn.111.019117

2. Wang N, Xu H, Du Q, et al. The effect of omega-3 polyunsaturated fatty acids on blood flow and endothelial function. Prostaglandins, Leukotrienes and Essential Fatty Acids. 2012;87(1):45–49. https://doi.org/10.1016/j.plefa.2012.02.001

3. Sadeghi N, Mirmiran P, Moghadam SK, et al. The relationship between dietary fat intake and menstrual cycle characteristics. Journal of Health, Population and Nutrition. 2020;39(1):22. https://doi.org/10.1186/s41043-020-00214-7

4. Safarinejad MR, Safarinejad S, Shafiei N, Safarinejad S. Effects of Omega-3 fatty acids on serum hormones, oxidative stress, and sperm parameters in infertile men with idiopathic oligoasthenoteratospermia. Reprod Biol Endocrinol. 2011;9:65. https://doi.org/10.1186/1477-7827-9-65

5. Coletta JM, Bell SJ, Roman AS. Omega-3 Fatty acids and pregnancy. Rev Obstet Gynecol. 2010 Fall;3(4):163-71. PMID: 21364848; PMCID: PMC3046737.

6. Al-Alousi T. A, Al-Allak M. M. A, Aziz A. A, Al-Ghazali B. S. The Effect of Omega-3 on the Number of Retrieved Ova, Fertilization Rate, and Embryo Grading in Subfertile Women Undergoing Intracytoplasmic Sperm Injection. Biomed Pharmacol J 2018;11(4).

7. Trop-Steinberg, Shivtia & Gal, Michael & Azar, Yehudith & Kilav, Rachel & Heifetz, Eli. (2024). Effect of omega-3 supplements or diets on fertility in women: A meta-analysis. Heliyon. 10. e29324. 10.1016/j.heliyon.2024.e29324.

8. Carlson SE, Colombo J, Gajewski BJ, Gustafson KM, Mundy D, Yeast J, Georgieff MK, Markley LA, Kerling EH, Shaddy DJ. DHA supplementation and pregnancy outcomes. Am J Clin Nutr. 2013 Apr;97(4):808-15. doi: 10.3945/ajcn.112.050021. Epub 2013 Feb 20. PMID: 23426033; PMCID: PMC3607655.