A new screening program is being introduced in South Australia in a bid to reduce the number of premature births.

Pregnant women in South Australia will be screened for omega-3 levels in a bid to reduce the number of premature births.

SA Pathology Clinical Service Director Tom Dodd says the service will be offered to women as part of existing antenatal testing used to detect a range of foetal anomalies such as neural tube defects and Down Syndrome.

"Pregnant women who have a low concentration of omega-3 in their blood are more likely to have an early birth, so it is important we identify this risk early and take action," Dr Dodd said.

"We hope this will lead to more women supplementing their diets with omega-3 where required, resulting in a reduction in the number of babies born prematurely."

The test will be offered to women expecting a single baby within the first 20 weeks of pregnancy.

The introduction of the screening comes after a study by the South Australian Health and Medical Research Institute (SAHMRI) found omega-3 fatty acids helped reduce the risk of premature delivery.

SAHMRI's Cochrane review, which examined almost 20,000 pregnancies, found taking omega-3 supplements reduced the overall risk of pre-term birth by 11 per cent.

It also significantly reduced the risk of a baby arriving before 34 weeks of pregnancy by 42 per cent.

SAHMRI Deputy Director Maria Makrides said the screening would be evaluated to examine the effectiveness of omega-3 supplementation and the long-term sustainability of the program.

"Babies who are born too soon, particularly those born before 34 weeks, can suffer numerous complications requiring long stays in hospital and, in some cases, long-term health and developmental problems," Professor Makrides said.

"By monitoring the number of tests done, the percentage of women with low omega-3 levels and how many babies are born early, we will be able to show whether this intervention is working."