Whether fish itself helps prevent preterm delivery is not clear, the researchers stress. But, they say, the finding is in line with the general advice that pregnant women eat up to two fish meals per week.

The study, reported in the journal Obstetrics & Gynecology, included 852 pregnant women who were at higher than average risk of preterm delivery because they had delivered early before.

Overall, 70 percent said they had averaged at least a half-serving of fish per week during the first 4 to 5 months of pregnancy. Of those women, 36 percent went on to have a preterm birth.

In contrast, that rate was 49 percent among women who ate fish no more than once a month.

Read the complete story by Reuters.