Researchers say taking fish oil supplements during pregnancy can help mums reduce their child's chances of developing asthma during the first five years of life.

A study of 695 newborns in Denmark has found the risk of developing asthma or a persistent wheeze dropped by a third among children whose mothers took daily fish oil supplements during their third trimester of pregnancy.

The children also had a reduced risk of developing lower respiratory tract infections such as bronchitis and pneumonia.