Researchers from South Australian Health and Medical Research Institute have today reported their initial findings from the ORIP Trial.
The women were randomly divided into two groups, and from around 12 to 34 weeks’ gestation half were given a daily dose of omega-3, or a vegetable oil capsule.
Lead researcher Dr Karen Best said the study included a a cross-section of women in the trial regardless of factors such as preterm birth risk, their baseline omega-3 levels or whether they were carrying one baby or more.
No significant difference was recorded between the groups in terms of early preterm birth (less than 34 weeks) nor number of adverse pregnancy or neonatal outcomes – contrary to previous findings.
“Our previous projects, including the DOMInO trial and Cochrane Review, suggested that omega-3 fats could prevent preterm birth,” Dr Best said.
“However, these latest results from ORIP indicate the benefits for preventing preterm birth might be best achieved through a targeted supplementation strategy rather than a ‘one-size-fits-all’ policy.”
The researchers believe the ORIP data suggest omega-3 supplementation could be most useful for women with a single pregnancy and those with low baselines levels of omega-3 in their blood.
Women who regularly eat fish or take a multivitamin supplement containing fish oil might not benefit from additional omega-3 supplements, they added.
Those taking part in the trial were given supplements containing either 900mg omega-3 oil, of which 800mg was DHA, or vegetable-oil capsules.
The study began before 20 weeks of gestation and continued to 34 weeks of gestation or delivery, whichever occurred first.
Early preterm delivery occurred in the case of 61 of 2734 pregnancies (2.2%) in the omega-3 group and 55 of 2752 pregnancies (2.0%) in the control group.
The researchers wrote in the New England Journal of Medicine: “The between-group difference was not significant (adjusted relative risk, 1.13; 95% confidence interval [CI], 0.79 to 1.63; P=0.50).”
They went on to state: “There were no significant differences between the groups in the incidence of interventions in post-term (>41 weeks of gestation) deliveries, in adverse events, or in other pregnancy or neonatal outcomes, except that a higher percentage of infants born to women in the omega-3 group than in the control group were very large for gestational age at birth. Percentages of serious adverse events did not differ between the groups.”
The study concluded that supplementation “did not result in a lower incidence of early preterm delivery or a higher incidence of interventions in post-term deliveries than control.”
Dr Best added the research team is now assessing what omega-3 levels the women had and the levels needed to reduce preterm births.
“And we’re actually seeing in some extra research that we’ve done, the women who were low in omega-3 and did get the fish oil capsules, it did actually help with preterm births.
“So, we’re not saying that omega-3 doesn’t work across the board, it just depends on what your personal levels are.”
The trial was funded by the Australian National Health and Medical Research Council and the Thyne Reid Foundation.
Source: New England Journal of Medicine
“A Randomized Trial of Prenatal n−3 Fatty Acid Supplementation and Preterm Delivery”
Authors: K Best, et al.