Women with low levels of omega-3 in early pregnancy are more likely to have premature births, according to a recent study.
Researchers from Harvard TH Chan School of Public Health, in collaboration with Statens Serum Institut in Copenhagen, discovered that pregnant women who have inadequate stores of long chain omega-3 fatty acids, in their first two trimesters, have a significantly higher risk of preterm birth. This is compared to women who had higher levels of the fatty acids.
"At a time when many pregnant women are hearing messages encouraging them to avoid intake of fish altogether due to mercury content, our results support the importance of ensuring adequate intake of long chain omega-3 fatty acids in pregnancy," lead author Sjurdur Olsen said.
The team examined data from the Danish National Birth Cohort, a nationwide study that follows 96,000 children in Denmark. And they analysed blood samples from 376 women who gave birth prior to 34 weeks of gestation and 348 women who had a full-term birth.
The blood samples, taken in the first and second trimester of each pregnancy, revealed that the women with the lowest readings of the long chain omega-3 fatty acids - eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA) - were 10 times more likely to have had an early pre-term birth, when compared to the women with the three highest readings.
Natural Fertility Specialist Tasha Jennings said omega-3 fatty acids were important during preconception and pregnancy, but should be consumed in a variety of ways.
"I think it should be cautioned that the results of this study do not mean that all pregnant women should rush out and take fish oil supplements," Ms Jennings said.
"A combination of a good quality supplement and healthy dietary choices are best."
She said omega-3 was also found in vegetarian sources like flaxseed oil, chia seeds, walnuts and soy.
"However, these sources provide omega-3 in the form of alpha-linolenic acid (ALA), which must then be converted to EPA and DHA in the body," she said.
"With a conversion rate of less than 5 per cent in most people, a great deal of ALA must be consumed to meet the same EPA/DHA levels as fish oil.
"I do recommend a good quality EPA/DHA supplement and a healthy intake of small fish, such as sardines and salmon, pre-conception to support healthy egg development and provide healthy levels during the early stages of pregnancy."
When looking for a supplement she recommended women chose one with a high EPA/DHA content.
"Many supplements will provide the same amount of fish oil, but the EPA/DHA levels will differ," she said.
"And choose a reputable brand as omega-3 can easily go rancid. Adequate stability measures must be taken to ensure this doesn't occur.
"Your fish oil shouldn't smell or taste too 'fishy'. Be aware of used by dates and store it in a cool, dark place."
Accredited nutritionist Tracie Connor said, while she strongly recommended women had an adequate omega-3 EPA/DHA intake, it was just part of the story.
"I think the study, like many others, shows clear findings, but it doesn't take into consideration other factors at play that could interfere, ie genetics," Ms Connor said.
"A message like this could easily confuse people also, conjuring beliefs that a single nutrient (omega-3 EPA/DHA) has the potential to cease chances of early preterm birth."
She said there was a lot of pressure on women, and many changing guidelines, to follow when pregnant.
"Yes, there's a lot of pressure. However, I hope many women understand how important good nutrition is during (before and after) pregnancy, for the health and wellbeing of the child and herself, hence why there's so much fuss about it," Ms Connor said.
"A healthy pregnancy is momentous and delivers so many benefits for baby and mum.
"General nutrition tips for mums-to-be include to maintain good water intake, enjoy plenty of colourful vegetables, combined with a balance of healthy fats, proteins and wholesome grains, limit stress and don't hesitate to ask for help, or say 'yes' when someone offers it."