The Fat Your Baby's Brain Needs: Why DHA During Pregnancy Matters

With all the conflicting advice about what to eat during pregnancy, one critical piece of information often gets lost in the noise: your baby's brain is made up of 10-20% DHA (an omega-3 fatty acid). Yet many of the best dietary sources of DHA during pregnancy are either heavily restricted or avoided entirely - fish due to mercury fears, cod liver oil due to outdated vitamin A concerns, and canned small fish due to BPA worries.

Here's the thing that really matters: more than half of your baby's brain is made of fat, and DHA (docosahexaenoic acid) makes up a significant portion of it. This isn't optional nutrition, it's foundational building material for your baby's developing brain and nervous system.

If you're not eating enough DHA-rich foods during pregnancy, your body will pull from your own stores to meet your baby's needs. This depletion is one reason why postnatal depression and 'baby brain' (that foggy, forgetful feeling many women experience after birth) are so common. Your body has literally given its own brain-supporting nutrients to your baby.

Beyond brain development, adequate DHA intake during pregnancy has been shown to reduce the risk of preeclampsia and preterm birth - two serious pregnancy complications that can affect both mother and baby.

Why DHA During Pregnancy Is Non-Negotiable for Brain Development

Let's address the elephant in the room: why are pregnant women so often told to limit or avoid the very foods that provide this essential omega-3 during pregnancy?

Mercury is a legitimate concern, but the blanket advice to avoid fish altogether throws the baby out with the bathwater (if you'll pardon the pun). The key is knowing which fish to choose and which to avoid.

Vitamin A concerns stem from outdated research that didn't distinguish between synthetic vitamin A and the natural, highly bioavailable form found in cod liver oil. When sourced well, cod liver oil is one of nature's most perfect pregnancy foods.

BPA is a valid consideration, but it's easily addressed by choosing BPA-free cans or fish packed in glass jars, or by opting for fresh options.

The fear-based messaging around these foods has left many pregnant women avoiding DHA-rich sources entirely, to the detriment of both their own health and their baby's development.

What DHA Actually Does for Brain Development in Pregnancy

DHA is a long-chain omega-3 fatty acid that serves as a primary structural component of the brain, cerebral cortex, skin, and retina. During pregnancy, particularly in the third trimester when your baby's brain is growing rapidly, the demand for DHA increases significantly.

For your baby, adequate DHA during pregnancy supports:

• Brain and nervous system development

• Visual development and eye health

• Cognitive function and IQ

• Reduced risk of developmental delays

• Healthy birth weight

  
  

For you as the mother, adequate DHA intake supports:

• Mood stability and emotional wellbeing

• Reduced risk of postnatal depression

• Mental clarity and cognitive function

• Lower risk of preeclampsia

• Reduced risk of preterm birth

  
  

Research has consistently shown that mothers with higher DHA levels during pregnancy have children with better cognitive outcomes, improved attention spans, and enhanced problem-solving abilities in early childhood.

The Best Sources of DHA During Pregnancy

The most bioavailable and effective sources of DHA are animal-based, particularly from marine sources. While plant-based omega-3s like ALA (alpha-linolenic acid) from flax seeds or chia seeds are beneficial, they require conversion to DHA in the body - a process that's inefficient at best, with only about 0.5-10% converting successfully.

Wild-Caught Fatty Fish: Safe Omega-3 Sources During Pregnancy

Small, oily fish are your best bet when choosing fish during pregnancy. These fish are lower on the food chain, meaning they accumulate far less mercury while still providing abundant omega-3 fatty acids.

Excellent choices include:

• Sardines (fresh, or canned in water or olive oil)

• Anchovies (fresh or in glass jars)

• Wild-caught salmon

• Mackerel (Atlantic mackerel, not King mackerel)

• Herring

Fish to limit or avoid due to higher mercury levels:

• Swordfish

• King mackerel

• Shark

• Tilefish

• Bigeye tuna

The key is choosing wisely, not avoiding fish altogether. The selenium naturally present in fish actually helps protect your body from mercury, and the benefits of eating low-mercury fish during pregnancy far outweigh the risks.

Cod Liver Oil

When sourced from clean waters and properly processed, cod liver oil provides not only DHA but also vitamin A and vitamin D - two nutrients that work synergistically to support healthy pregnancy and foetal development.

The fear around vitamin A in pregnancy stems from studies using high doses of synthetic vitamin A, which is very different from the naturally occurring, highly bioavailable form found in cod liver oil. The vitamin A in cod liver oil is fat-soluble retinol, which your body can regulate and use safely.

Look for:

• Products tested for purity and free from oxidation

• Brands that source from clean, cold waters

Canned Fish

Canned sardines and anchovies are convenient, affordable, and shelf-stable options that make it easy to include DHA-rich foods in your diet regularly.

Tips for choosing canned fish:

• Look for BPA-free cans or fish packed in glass jars

• Choose fish packed in water, olive oil, or their own oil (avoid vegetable oils)

• Check labels for added ingredients, simpler is better

• Wild-caught

Fish Roe (Caviar)

Often overlooked, fish roe is incredibly rich in DHA, choline, and B vitamins. Wild salmon roe, in particular, is an excellent addition to the preconception and pregnancy diet.

How Much DHA Do You Actually Need During Pregnancy?

Current research suggests pregnant women should aim for at least 200-300mg of DHA per day, with many experts recommending closer to 500mg during the third trimester when fetal brain development accelerates.

To put this in perspective:

• 100g of wild-caught salmon: ~1,500-2,500mg combined EPA and DHA

• 100g of sardines: ~1,000-1,500mg combined EPA and DHA

• 1 teaspoon of cod liver oil: ~400-500mg DHA (varies by brand)

You don't need to eat fish every single day, but incorporating DHA-rich foods 2-3 times per week, supplemented with high-quality cod liver oil if appropriate for your situation, can help ensure you're meeting your omega-3 needs during pregnancy.

What I See in Clinical Practice

When I work with clients to ensure they're getting enough DHA during pregnancy, especially in the third trimester, prioritising wild-caught fish, smaller fish like sardines and anchovies, and quality cod liver oil when appropriate, they consistently report feeling mentally clearer and more emotionally balanced during their pregnancies.

The difference is often quite noticeable. Women who were experiencing brain fog, mood swings, or anxiety often find these symptoms improve significantly when we address DHA intake alongside other nutritional foundations.

Postnatally, the women who maintained adequate DHA intake during pregnancy tend to report:

• Better mood stability in the fourth trimester

• Clearer thinking and less "baby brain"

• Easier emotional regulation

• More energy and resilience

Beyond Supplements: Food First

While DHA supplements (usually derived from fish oil or algae) can be helpful, I always encourage a food-first approach when possible. Whole foods provide not just DHA, but a complete package of complementary nutrients - selenium, iodine, B vitamins, protein, and other beneficial compounds that work synergistically.

When you eat sardines, you're not just getting DHA. You're also getting highly bioavailable calcium from the tiny bones, vitamin D, B12, selenium, and protein. When you eat wild salmon, you're getting astaxanthin (a powerful antioxidant), vitamin D, and B vitamins alongside those omega-3s.

Supplements have their place, particularly for women who struggle to eat fish regularly or who have higher needs, but they shouldn't replace whole food sources entirely when those foods are accessible and well-tolerated.

Practical Ways to Include DHA-Rich Foods

If you're not used to eating fish regularly, it can feel daunting to suddenly start incorporating it multiple times per week. Here are some simple, practical ways to make it happen:

Sardines:

• Mash onto sourdough toast with avocado and a squeeze of lemon

• Toss into a salad with greens, olives, and feta

• Mix into scrambled eggs

• Add to pasta with garlic, olive oil, and fresh herbs

Salmon:

• Bake with herbs and lemon, serve with roasted vegetables

• Make salmon patties or burgers

• Add to frittatas or quiches

• Mix into rice bowls with vegetables

Anchovies:

• Blend into salad dressings for depth of flavour

• Add to tomato-based pasta sauces

• Top pizza or flatbreads

• Mix into butter for anchovy butter on bread or vegetables

Cod liver oil:

• Take straight off the spoon (chase with orange juice if needed!)

• Mix into smoothies

• Drizzle over food after cooking

What About Vegetarian or Vegan Diets?

If you follow a plant-based diet, meeting DHA needs during pregnancy requires extra attention and planning. ALA from flaxseed, chia seeds, and walnuts is beneficial, but the conversion rate to DHA is very low - often less than 5%.

Algae-based DHA supplements are the most effective plant-based option, as they provide pre-formed DHA without requiring conversion. These supplements are derived from the same algae that fish eat to obtain their DHA, essentially cutting out the middleman.

If you're following a vegetarian or vegan diet during pregnancy, I strongly recommend:

• Working with a qualified practitioner to monitor your DHA levels

• Taking a high-quality algae-based DHA supplement

• Ensuring adequate intake of ALA from plant sources

• Monitoring your baby's development closely with your healthcare provider

The Bottom Line on DHA During Pregnancy

Your baby's brain is literally made of fat, and DHA is a crucial component of that fat. Fear-based advice that tells you to avoid the very foods that provide this essential omega-3 during pregnancy does more harm than good.

By choosing wisely, prioritising small, wild-caught fish, quality cod liver oil when appropriate, and BPA-free canned or jarred options, you can safely provide your baby with the building blocks they need for optimal brain development while supporting your own mental and emotional wellbeing during pregnancy and beyond.

Don't let outdated fear-mongering rob you and your baby of this vital nutrition. Make informed choices, know your sources, and nourish your body with the foods it needs to grow a healthy baby and maintain your own vitality.

Are you eating enough nutrient-dense seafood during pregnancy or while trying to conceive? What's your go-to source for omega-3 during pregnancy?