According to the Centers for Disease Control, more than 23,000 American infants died in 2016.

And the CDC identified premature birth and low birth-weight as the second leading cause:

  1. Birth defects
  2. Preterm birth and low birth weight
  3. Sudden infant death syndrome
  4. Maternal pregnancy complications
  5. Injuries (e.g., suffocation)

The average healthy pregnancy lasts between 38 and 42 weeks, and births occurring before the 37-week mark are defined as premature — and the risk of death or poor health rises the earlier a baby is born.

The causes of premature birth are not always clear, but can include these risk factors:

  • Smoking
  • Urinary tract or vaginal infections
  • Mother’s age (too young or too old)
  • Malnutrition, including vitamin deficiencies
  • Psychological, environmental, parental, and genetic factors
  • Maternal depression and/or use of antidepressants (e.g., Prozac)
  • Chronic disease (diabetes, hypertension, anemia, asthma, thyroid disease)

However, some of the biggest risk factors are poverty, low education, and lack of access to prenatal care — any of which can promote or exacerbate the risk factors listed above.

Premature babies experience higher risks for a range of long-term health deficits, including impaired vision, brain development, intestinal development, hearing, lung function, cardiovascular health, mental health, and learning capacity.

(Earlier this year, we reported on the long-overdue FDA approval of an intravenous omega-3 nutritional formula for babies born prematurely, without fully developed intestinal tracts: see FDA Okays Life-Saving Fish Oil IV for Sick Children and its links to our earlier coverage of this frustrating tale of the agency’s negligence.)

Shockingly, researchers from Johns Hopkins University recently reported that — compared with the world’s 19 other wealthiest countries — American babies are three times more likely to die from premature birth (Thakrar AP et al. 2018).

But this risk is not distributed evenly, with the highest rates of premature births seen among lower-income mothers.

The Johns Hopkins team blamed America’s high rate of premature births on childhood poverty and a comparatively weaker social safety net.

And a 2013 study by the United Nations Children’s Fund found that the United States had the second highest childhood poverty rate among 35 developed nations.

The United States has been experiencing growing income inequality since the 1980s — which may explain why America’s rate of childhood poverty resembles the rates seen in much poorer countries.

There’s been growing evidence that omega-3 fatty acids from seafood (DHA and EPA) can reduce the risk of premature birth and blunt its negative impacts.

For example, see Omega-3 DHA May Cut Premature Births and its links to related reports. And visit our Healthy Mom & Baby page for more information

And the results of a rigorous new evidence review confirm that dietary fish and/or omega-3 fish oil can help reduce the risk of preterm birth.

Evidence review finds that omega-3s reduce the risk of premature birth
An international team recently reported the results of an evidence review they performed using the rigorous standards of the widely respected Cochrane Collaboration.

Scientists from institutions Australia and Denmark took a close look at clinical trials that had examined the potential for seafood-source omega-3s (DHA and EPA) to reduce the risk of premature births.

They scrutinized 70 randomized trials and found that increasing daily intake of these omega-3s produce three key benefits for pregnant women and their fetuses:

  • Reduces the risk of premature birth (less than 37 weeks) by 11%.
  • Reduces the risk of very early premature baby (less than 34 weeks) by 42%.
  • Reduces the risk of low-weight births — less than 5.5 lbs. (2500g) — by 10%.

As lead author Philippa Middleton said, “There aren’t many options for preventing premature birth, so these findings are very important for pregnant women, babies and the health professionals who care for them. This is one of the reasons omega-3 supplementation in pregnancy is of such great interest to researchers.”

The new Cochrane evidence review is a follow up to one performed in 2006, which didn’t find enough evidence to support the routine use of omega-3 fish oil supplements during pregnancy.

The authors of this updated review, covering an additional 12 years of published research, concluded that there’s high quality evidence that supplemental omega-3s offer an effective way to help prevent preterm birth.

Dr. Middleton made an important point about dosing: “Many supplements currently on the market don’t contain the optimal dose or type of omega-3 for preventing premature birth. Our review found the optimum dose was between 500 and 1000 milligrams (mg) of long-chain omega-3 fats (containing at least 500mg of DHA) daily, starting at 12 weeks of pregnancy.”

The paper’s authors noted that there are 23 more clinical trials in progress involving more than 5,000 women, and as they wrote, “no more RCTs [randomized clinical trials] are needed that compare omega-3s against placebo or no intervention.”

In other words, it’s now clear that sufficiently high doses of supplemental omega-3s help reduce the risk of premature births.

About Cochrane Reviews
Scientists worldwide perceive Cochrane Reviews as the highest standard in evidence-based health care.
Cochrane — also known as the Cochrane Collaboration — is a charity governed by a board of trustees, half of whom are elected by scientists who are members of eight Networks of Cochrane Review Groups located around the world.

The authors of a Cochrane Review gather all the existing research on a topic that meets minimum quality criteria, and then assess it using strict analytical guidelines to determine what conclusive evidence — if any — that body of research provides.

Cochrane Reviews aren’t necessarily perfect, because, like any evidence review their limited by the quality of the available studies.

In fact, it’s possible to find fault with the methods or conclusions of a given Cochrane Review, as we and our scientific advisors have occasionally done.

For example, see our comments about a Cochrane Review in Study Doubts Omega-3s’ Heart Health Benefits. While we found some fault with it, the authors of that review also acknowledged the limitations of the evidence they were dealing with.

And, had that review been conducted a few months later, the authors could’ve included the findings from two recent clinical trials, both of which found that supplemental omega-3s produced very substantial reductions in cardiovascular health risks: see Omega-3s Score 2nd Big Heart Win and Omega-3s’ Heart Value Vindicated in Long, Large Clinical Trial.

But no other organization is more widely respected for the rigor of its analytical standards, making the results of a Cochrane Review worthy of special attention.


  • Blencowe H, Cousens S, Chou D, Oestergaard M, Say L, Moller AB, Kinney M, Lawn J; Born Too Soon Preterm Birth Action Group. Born too soon: the global epidemiology of 15 million preterm births. Reprod Health. 2013;10 Suppl 1:S2. doi: 10.1186/1742-4755-10-S1-S2. Epub 2013 Nov 15. Review.
  • Makrides M, Best K. Docosahexaenoic Acid and Preterm Birth. Ann Nutr Metab. 2016;69 Suppl 1:29-34. Epub 2016 Nov 15. Review.
  • Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega‐3 fatty acid addition during pregnancy. Cochrane Systematic Review - Intervention Version published: 15 November 2018. Issue 11, Article: CD003402, doi: 10.1002/14651858.CD003402.pub3
  • Thakrar AP, Forrest AD, Maltenfort MG, Forrest CB. Child Mortality in The US And 19 OECD Comparator Nations: A 50-Year Time-Trend Analysis. Health Aff (Millwood). 2018 Jan;37(1):140-149. doi: 10.1377/hlthaff.2017.0767.