Omega-3 during Pregnancy — DHA Requirements, Dosage & Practical Tips

During pregnancy, your nutritional requirements increase considerably — and omega-3 fatty acids, above all DHA (docosahexaenoic acid), are among the most important micronutrients of this phase. DHA is a central building block of the foetal brain and retina, and is absorbed in particularly large quantities by the baby's body during the final trimester. Studies show that an adequate DHA supply is closely linked to the child's cognitive development and visual acuity. Nevertheless, most pregnant women in the UK and Germany do not reach the recommended intake levels. In this article you will learn how much DHA you really need during pregnancy, which sources are best, what to look for in supplements — and why you should ideally start supplementing before conception.

Why DHA is So Important during Pregnancy

DHA (docosahexaenoic acid) is a long-chain omega-3 fatty acid that the human body cannot produce in sufficient quantities itself. During pregnancy, your baby is entirely dependent on your DHA supply — it can absorb the fatty acid via the placenta, but only if you have enough available.

DHA as a Building Block of the Brain and Retina

The foetal brain is composed of a considerable proportion of fat — and DHA makes up up to 40% of the fatty acids in the cerebral cortex. The retina of the eye contains even higher concentrations: around 60% of its fatty acids are DHA. This fatty acid is not merely a passive structural component, but actively influences signal transmission between nerve cells and the fluidity of cell membranes — both critical for normal neurological development.

The European Food Safety Authority (EFSA) has established an approved health claim on the basis of this evidence: a daily intake of 200 mg DHA by the mother contributes to the normal brain and eye development of the infant — both during pregnancy and during breastfeeding.

When Brain Development is Most Intense

The child's brain development does not proceed evenly throughout pregnancy. The most intensive phase of DHA accumulation in the foetal brain takes place in the third trimester — between weeks 28 and 40 of pregnancy. During this period, several milligrams of DHA are transferred daily from the maternal blood via the placenta. Studies show that premature babies, who do not complete this phase intrauterinely, often have lower DHA levels in the brain than full-term babies.

This means: if you only start DHA supplementation in the third trimester, you will still have a positive effect — but you may miss the opportunity to build up sufficient DHA reserves early on. Ideally, you should start before conception. A publication in the American Journal of Clinical Nutrition (Innis, 2007, PMID: 17556680) confirms that maternal DHA stores have a decisive influence on foetal DHA supply.

How Much Omega-3 Do You Need during Pregnancy?

The question of the right dosage is particularly relevant during pregnancy. Various expert organisations have issued recommendations that differ slightly, but agree on the key point: DHA requirements increase significantly during pregnancy.

Organisation	Recommended EPA+DHA total	Of which DHA	Note
EFSA	250 mg + 200 mg extra DHA	min. 200 mg extra	Approved health claim
DGE (German Nutrition Society)	min. 200 mg DHA/day	200 mg DHA	In addition to baseline intake
WHO / FAO	300–450 mg EPA+DHA	min. 200 mg DHA	For pregnant and breastfeeding women
International Society for the Study of Fatty Acids (ISSFAL)	500 mg EPA+DHA	min. 200 mg DHA	Upper recommendation for optimal supply

In practice, many obstetricians recommend a daily intake of 500–600 mg EPA+DHA during pregnancy, of which at least 200–300 mg should be DHA. This is significantly more than the average actual intake in Germany and the UK, which in women of childbearing age often falls below 150 mg DHA per day — a considerable deficit.

Measuring Your Own Status: The Omega-3 Index

Rather than taking supplements blindly, it makes sense to know your own omega-3 status. The Omega-3 Index measures the proportion of EPA and DHA in the total fatty acids of red blood cells, providing information about long-term supply — independently of the last meal. For pregnant women, an Omega-3 Index of 8–11% is the target. Most people in Germany and the UK are at 5–6%, which is considered suboptimal.

You can carry out the test conveniently at home — on our page Omega-3 Index Testing you will find all the information on how it works and what to do with the result. Particularly during pregnancy, a baseline test is useful to check whether your intake is actually sufficient.

Omega-3 Sources during Pregnancy: Food vs. Supplements

Oily Fish: Best Natural Source, with Limitations

Oily sea fish such as salmon, mackerel, herring and sardines are the richest natural sources of EPA and DHA. A 150 g portion of Atlantic salmon provides between 1,500 and 3,000 mg EPA+DHA depending on origin and feeding — more than enough for an entire day. The German Nutrition Society recommends eating fish twice a week, including oily sea fish on one occasion.

However, there are important restrictions during pregnancy: large fish such as tuna (especially fresh), swordfish, shark and king mackerel can contain high amounts of methylmercury, which crosses the placental barrier and has neurotoxic effects. The German Federal Institute for Risk Assessment (BfR) therefore recommends that pregnant women avoid these fish species and instead choose small, oily fish (herring, sardines, mackerel) which accumulate significantly smaller amounts of contaminants.

Plant-based Sources: ALA Barely Helps

Linseed, walnuts and rapeseed oil contain the short-chain omega-3 fatty acid ALA (alpha-linolenic acid). The body can convert ALA into EPA and DHA in principle — but the conversion rate is extremely inefficient: only around 5–10% of ALA is converted to EPA, and less than 1% to DHA. Plant-based ALA sources are therefore not sufficient for foetal DHA supply. Those who do not eat fish absolutely need a supplement.

Supplements: Fish Oil, Krill Oil or Algae Oil?

In the omega-3 supplement market, you have three main categories to choose from:

Fish oil is the most commonly used form. It contains EPA and DHA in varying ratios depending on fish species and processing. For pregnant women the key is: the product should have been tested for heavy metals, dioxins and PCBs, have a low TOTOX value (below 26), and preferably be in triglyceride form, as this is more bioavailable than the ethyl ester form.

Krill oil contains EPA and DHA in phospholipid form, which enables good bioavailability. However, the absolute EPA/DHA content per capsule is usually lower than in fish oil, so you need more capsules or a higher dose to achieve the same amount. Krill oil tends to be more expensive.

Algae oil is particularly interesting for pregnant women: it is derived from marine microalgae — the same organisms from which fish obtain their DHA. Since algae are cultivated in controlled tanks without heavy metal contamination, algae oil is practically free from contaminants. A study (Geppert et al., 2005, PMID: 16359745) shows that microalgal DHA is just as bioavailable as DHA from fish. Algae oil is also vegan and is therefore suitable for vegetarians and vegans. The only drawback: many algae oil products contain more DHA than EPA — those who also wish to supplement EPA should read labels carefully.

More information on quality criteria and what to look for when buying can be found in our detailed omega-3 supplement buying guide.

Quality and Safety: What to Pay Special Attention to during Pregnancy

During pregnancy you are not alone — what you consume also reaches your baby. Higher standards are therefore appropriate when choosing an omega-3 supplement than outside of pregnancy.

Heavy Metals and Contaminants

Look for supplements that present their purity analyses transparently. Reputable manufacturers publish regular batch tests by independent laboratories. Key parameters are:

• Mercury: Must be below the legal limit (0.1 mg/kg in the oil)
• Lead and cadmium: Also listed on manufacturer certificates
• Dioxins and PCBs: EU maximum values for fish oil apply; good manufacturers fall well below these

TOTOX Value: Freshness is Critical

Oxidised fish oil can not only smell unpleasant, but also contain undesirable breakdown products. The TOTOX value (Total Oxidation Value) is a measure of oil oxidation — it is composed of double the anisidine value plus the peroxide value. According to the GOED standard (Global Organization for EPA and DHA Omega-3s), the TOTOX value should be below 26. High-quality supplements come in at below 10. Ensure the product is packaged in opaque capsules or dark bottles and contains an antioxidant (usually vitamin E / tocopherol).

Certifications as Guidance

Certificates such as IFOS (International Fish Oil Standards), Friend of the Sea or MSC indicate that the product has been independently tested for quality and sustainability. They do not replace your own critical assessment, but are a good indicator of credibility.

The Right Time: When to Start

Before Conception: The Best Strategy

Ideally, you should not wait for a positive pregnancy test before thinking about your omega-3 supply. DHA accumulates in your body's stores over weeks and months — a one-off boost shortly before or after conception is of little effect. If you are planning to become pregnant, ideally start daily DHA supplementation three to six months beforehand.

This has another advantage: many women do not yet know they are pregnant in the first weeks — and precisely this early phase is critical for cell division and initial organ development. If your DHA reserves are already well built up, your baby is covered from the very start. On our page about Omega-3 and Fertility you will find further information on the role omega-3 can play in fertility.

In the First Trimester: Start as Soon as Possible

If you only found out about your requirements once you were pregnant: no cause for concern — start now. In the first trimester, the basic structures of the nervous system develop, even though brain growth and intensive DHA accumulation begin later. Early supplementation ensures your body stores are well filled for the second and third trimester.

In the Third Trimester: Highest Requirements

Between weeks 28 and 40 of pregnancy, the foetal brain grows fastest. During this phase, the placenta actively transfers DHA from mother to child — even at the expense of the mother's DHA reserves if intake is insufficient. Studies show that the Omega-3 Index of many pregnant women falls significantly towards the end of pregnancy if they do not supplement. Pay particular attention in the third trimester to consistent, daily intake.

Breastfeeding: It Is Worth Continuing

The increased DHA requirement does not end with birth. Through breast milk you continue to supply your baby with DHA — the DHA concentration in breast milk depends directly on your own intake. Studies show that the DHA concentration in breast milk is two to three times higher in supplementing mothers than in those who do not supplement. What is important during breastfeeding is covered on our page about Omega-3 during Breastfeeding.

Fish Oil vs. Algae Oil during Pregnancy: Which Is Better?

Both fish oil and algae oil can be used beneficially during pregnancy. The decision depends on your preferences, dietary habits and the specific product.

One key difference lies in the contaminant situation: while purity analysis is decisive for fish oil, algae oil from controlled cultures is structurally cleaner — marine microalgae do not accumulate heavy metals from the sea when cultivated in closed systems. For pregnant women who want to be especially cautious about safety, algae oil is therefore a very attractive option.

In terms of content, algae oil typically provides more DHA than EPA. Many specialist pregnancy products based on algae contain 200–300 mg DHA per capsule, often with significantly less EPA. This is unproblematic during pregnancy, since DHA is the primary building block needed — EPA is also valuable for cardiovascular functions, but for foetal development DHA takes priority.

Detailed information on the health aspects of omega-3 during pregnancy, including study results on premature birth and child development, can be found in our medical article Omega-3 in Pregnancy — Scientific Overview.

Practical Tips for Taking Supplements

Take with Meals

Omega-3 fatty acids are fat-soluble — their absorption improves considerably when taken together with a fatty meal. Best to take your supplement with lunch or dinner. Taking it on an empty stomach can also worsen nausea in some women — a common complaint during pregnancy.

Avoiding a Fishy Aftertaste

A common problem with fish oil capsules is a fishy aftertaste or burping. These symptoms often indicate an oxidised oil — a quality indicator you should take seriously. High-quality, fresh supplements have barely any taste of their own. Alternatively, you can briefly freeze the capsules — this slows their release in the stomach and significantly reduces the aftertaste.

Consistency Is More Important than Maximum Dose

A daily intake of 250–500 mg DHA over weeks and months is more effective than sporadic high doses. DHA is gradually incorporated into cell membranes — this is a continuous process, not an acute effect. Set a fixed time (e.g. always with dinner) and integrate the supplement into your routine.

Dosage Calculator and Individual Advice

How much omega-3 you should specifically take also depends on your current diet, body weight and measured Omega-3 Index. With our Omega-3 Requirements Calculator you can get an individual estimate based on your personal data. For questions about supplementation during pregnancy — especially if you have pre-existing conditions or are taking other medications — always consult your obstetrician or midwife.

Frequently Asked Questions (FAQ)

Further target-group articles — on omega-3 for athletes, seniors and vegans — can be found in the For You overview.