Omega-3 supplements could reduce the number of premature births

Giving omega-3 supplements to pregnant women with low levels of this fatty acid could prevent about 14 per cent of early preterm births, according to data from an Australian trial. The finding has inspired a world-first screening and treatment programme for omega-3 deficiencies in pregnant women in South Australia.

Omega-3 fatty acids are found in fish and are known to protect heart and brain health, and there is evidence that they are also important in pregnancy. For example, observational studies have shown that eating fish regularly during pregnancy seems to lower the risk of preterm birth.

A few years ago, Maria Makrides at the South Australian Health and Medical Research Institute and her colleagues ran a trial in which they randomly assigned 5500 pregnant women to have either 1 gram of omega-3 per day in the form of fish oil capsules or a placebo, starting any time before 20 weeks of gestation.

They found that in women who started out with low levels of omega-3 in their blood, supplements of omega-3 fatty acids reduced the risk of birth happening before 34 weeks of gestation by 77 per cent. The placebo had no effect on the risk of such early premature birth.

But for women who already had high omega-3 levels, taking the omega-3 supplements actually increased their risk of these preterm births. This suggests that the supplements should only be recommended to pregnant women with low omega-3 levels, although multivitamins containing small omega-3 doses are fine for women who already have high levels, says Makrides.

On the back of these results, Makrides has helped launch a screening programme in the state of South Australia that offers free blood tests to all pregnant women to identify and treat those who are low in omega-3. About 3000 women have been screened since May 2021 and so far 17 per cent have been found to have low omega-3 levels.

Based on the earlier clinical trial results, Makrides and her team estimate that recommending omega-3 supplements to these women with low omega-3 levels could prevent 1 in 7 early preterm births across South Australia.

Currently, there are few effective ways to prevent premature births, which increase the risk of death or disability in babies, says Makrides, who will present the first results of the screening programme at the annual scientific meeting of the Royal College of Pathologists of Australasia on 6 March.

“Finding ways to prevent premature birth is one of the highest priorities in maternal and child health,” she says.

It isn’t clear why omega-3 fatty acids protect against preterm birth, but there is some evidence that it influences pre-labour changes to the cervix and contractions of the uterus, says Makrides.