Omega 3 fatty acids fish oil prenatal vitamin

Preterm Birth Prevention: Omega-3 Fatty Acids

You’ve probably heard about Omega-3’s and their relationship to heart health.

But did you know that they also may play an important role in preventing preterm birth and other pregnancy complications? Let’s dive in and talk about these important fatty acids, how they may prevent (unplanned) early delivery, and how to make sure you are getting enough to support a healthy pregnancy.

What is preterm birth?

Preterm birth is a birth that occurs before 37 weeks. These births can happen spontaneously, or as part of medical intervention for pregnancy complications, and can put the infant and the mother at higher risk of additional complications after delivery. In the case of spontaneous preterm births, the inflammatory process that initiates labor starts too soon. Therefore, it would make sense that anti-inflammatory nutrients would help slow this process, preventing preterm labor. Omega-3 fatty acids, primarily docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are known for their incredible anti-inflammatory properties and have been shown to produce compounds that control the inflammatory response in the uterus and prevent preterm birth.

The Research

A recent study published in EBioMedicine adds to the current body of evidence linking the relationship between omega-3 fatty acids and the prevention of preterm births.

The total study population included 91,661 women enrolled in the Danish National Birth Cohort. Researchers identified 376 women who had experienced preterm birth from this large study group. The plasma concentrations of EPA and DHA were measured during the first and second trimesters of these pregnancies, which had ended in early delivery.

In this study, researchers found that women who had the lowest concentrations of omega-3s in their plasma had a risk of preterm birth that was 10 times higher compared to women with the highest levels. To get a better picture of the difference in concentration, women with the lowest concentrations had 1.6% or lower DHA and EPA in their plasma, while the highest had 1.8% or higher. Such a small difference in these critical fats made a huge difference in pregnancy outcomes.

Previous studies have pointed to a relationship between DHA and EPA consumption and the reduction of preterm birth.

A review published in 2016 found that supplementation with DHA and EPA reduced the risk of early preterm birth (<34 weeks) by 58% and of any preterm birth (<37 weeks) by 17%. In a 2007 study, researchers found that supplementation of fish oil in high-risk pregnant women with previous pregnancy complications reduced the risk of preterm delivery in women who ate just 4 to 6 ounces of fish per week.

How to Get Enough Omega-3 Fatty Acids

The omega-3 fats, EPA and DHA, are found in tuna, cod, salmon, anchovies, and other cold-water fish. Research points to eating >12oz of fish a week as being best for preventing pregnancy risks and promoting long term health outcomes for baby, including higher IQ scores (Hebbeln et al, 2007).

What about supplementation?

It's not easy to consistently consume over 12oz of fish a week. To account for gaps and provide additional support, it is wise to consider supplementing with a good quality fish oil supplement.

Look for brands that provide independent testing reports of contaminants. Avoid any company that doesn’t do 3rd party independent testing (or won’t openly provide the results of their testing). 

What do I look for in a Fish Oil Supplement?

Find a natural supplement that exceeds the standards of most fish oils by looking for a product that is sustainably-sourced and has been tested for: 

  • Potency and identity (i.e. does the product have what it claims to have in it)
  • Purity & safety (tested for PCPs, Dioxins and Furans, Dioxin-like PCBs and radioactivity)
  • Stability (this is SO important with fish oil! "Stability" means exactly what is sounds like: Does the fish oil become oxidized, rancid, or degrade in any other way over time? If no, it is considered "stable")
  • Heavy metals including mercury, lead, inorganic arsenic, and cadmium

This is the bare minimum in criteria you should be screening for. Nothing less is acceptable when it comes to nourishing mom and baby. 

Plant-based omega-3 fatty acid sources & natural supplements

Individuals who do not eat fish or take fish oil can get omega-3 fatty acids from plant-based sources including walnuts, flaxseed, or chia. But, it is important to note that plant-based sources must first be converted into EPA or DHA. This conversion is unfortunately quite inefficient, making fish the preferable source. Some prenatal vitamins may also contain DHA and EPA, though the concentration of these fatty acids may vary by brand. Check the label before you purchase and know that often, a prenatal will not/cannot contain enough, so it will need to be taken as a separate supplement. In fact, I’m always suspect of prenatal vitamins that claim they contain DHA, but are gummies or just a small capsule, because it’s just not possible to fit enough omega-3 fatty acids (plant-based or not) into such a small dose. It’s usually best to supplement separately and focus on dietary sources.

What's the takeaway?

Overall, there is an increasing body of research showing that incorporating omega-3 fatty acids into your prenatal routine can significantly reduce the risk for preterm birth and help you achieve a healthy pregnancy.

If you choose a supplement wisely, the risk in taking omega-3 fatty acids is very minimal. This makes me wonder: why aren’t omega-3 fatty acids recommended as the standard of care? 

*The information provided on this website is provided for educational purposes only and should not be treated as medical advice. FullWell makes no guarantees regarding the information provided or how products may work for any individual. If you suffer from a health condition, you should consult your health care practitioner for medical advice and before introducing any new products into your health care regimen. For more information please read our terms and conditions.


1. Olsen, S.F, et al. "Plasma Concentrations of Long Chain N-3 Fatty Acids in Early and Mid-Pregnancy and Risk of Early Preterm Birth" EBioMedicine
Volume 35, (2018): 325-333, ISSN 2352-3964

2. Hibbeln, Joseph R., et al. "Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study." The Lancet 369.9561 (2007): 578-585.