Researchers say no more RCTs are needed

Definitive link? Cochrane review finds omega-3 intake in pregnancy slashes risk of preterm birth

By Nathan Gray

- Last updated on GMT

iStock / Pixelistanbul
iStock / Pixelistanbul
A review of more than 70 clinical trials has found that increased intakes of long-chain omega-3 fatty acids during pregnancy is linked to a lower risk of premature births.

The updated Cochrane Review​, pooled data from almost 20,000 women involved in more than 70 randomised trials that compared supplementation of omega-3s with placebo – finding that higher intakes as a result of supplementation reduces the risk of premature births.

Specifically, the review finds that omega-3 fatty acids – and particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) found in fatty fish and fish oil supplements:

  • lowers the risk of having a premature baby (less than 37 weeks) by 11% (from 134 per 1000 to 119 per 1000 births
  • lowers the risk of having an early premature baby (less than 34 weeks) by 42% (from 46 per 1000 to 27 per 1000 births)
  • reduces the risk of having a small baby (less than 2500g) by 10%

“There are not many options for preventing premature birth, so these findings are very important for pregnant women, babies and the health professionals who care for them,”​ says Cochrane Pregnancy and Childbirth lead author Associate Professor Philippa Middleton.

“We don’t yet fully understand the causes of premature labour, so predicting and preventing early birth has always been a challenge. This is one of the reasons omega-3 supplementation in pregnancy is of such great interest to researchers around the world.”

Nutra notes: A global issue

Premature birth is the leading cause of death for children under 5 years old worldwide, accounting for close to one million deaths annually, note the researchers behind the new review.

“We know premature birth is a critical global health issue, with an estimated 15 million babies born too early each year,”​ commented Middleton.

What is a Cochrane Review?

Cochrane Reviews are systematic reviews of primary research in human health care and health policy.

They are internationally recognised as the highest standard in evidence-based health care, and are published online in The Cochrane Library​.

Each systematic review addresses a clearly formulated question; for example: Can antibiotics help in alleviating the symptoms of a sore throat?

All ​existing research on a topic that meets certain criteria is searched and collated, and then assessed using strict guidelines, to establish whether or not there is conclusive evidence.

The team noted that premature babies are at higher risk of a range of long-term conditions including visual impairment, developmental delay and learning difficulties.

“While the length of most pregnancies is between 38 and 42 weeks, premature babies are those born before the 37 week mark – and the earlier a baby is born, the greater the risk of death or poor health,”​ Middleton added.

Updated review: No more evidence needed

The new review updates a 2006 publication, which at the time concluded that there was not enough evidence to support the routine use of omega-3 fatty acid supplements during pregnancy.

More than a decade later, the updated review concludes that there is high-quality evidence for omega-3 supplementation being an effective strategy for preventing preterm birth.
“Many pregnant women around the world are already taking omega-3 supplements by personal choice rather than as a result of advice from health professionals,”​ says Middleton.

Indeed, with a further 23 ongoing trials are still to report on over 5000 women, the authors noted that “no more RCTs are needed that compare omega-3 LCPUFA against placebo or no intervention.”

The Global Organization for EPA and DHA Omega-3s (GOED) said it is ‘very happy’ to see additional positive news about omega-3s, at a time where other important studies have also shown significant positive results.

“So often we hear that more research is needed, so it’s interesting to note that the authors indicated that ‘More studies comparing omega-3 LCPUFA and placebo (to establish causality in relation to preterm birth) are not needed at this stage.’,”​ GOED noted.

However, the authors of the report did suggest that further follow-up of completed trials is needed to assess longer-term outcomes for mother and child, to improve understanding of metabolic, growth and neurodevelopment pathways in particular, “and to establish if, and how, outcomes vary by different types of omega-3 LCPUFA, timing and doses; or by characteristics of women.”

fish oil omega 3 supplements pills oils

Optimal dose

While the evidence of benefit seems definitive, Middleton says it is ‘worth noting’ that many supplements currently on the market do not contain the optimal dose or type of omega-3 for preventing premature birth.

“Our review found the optimum dose was a daily supplement containing between 500 and 1000 milligrams (mg) of long-chain omega-3 fats (containing at least 500mg of DHA) starting at 12 weeks of pregnancy,”​ she noted.

Based on the finding from the review, the Australian team behind the analysis also provided guidance for health care professionals​.
“Ultimately we hope this review will make a real contribution to the evidence base we need to reduce premature births, which continue to be one of the most pressing and intractable maternal and child health problems in every country around the world.”

Source: Cochrane Database of Systematic Reviews 2018
Issue 11, Article: CD003402, doi: 10.1002/14651858.CD003402.pub3
“Omega‐3 fatty acid addition during pregnancy”
Authors: Middleton  P, Gomersall  JC, Gould  JF, Shepherd  E, Olsen  SF, Makrides  M. 

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