Women who eat too much fat and sugar foods and takeaway before they become pregnant are more likely to have a preterm birth, a new study said Friday.

The study, published in the U.S. Journal of Nutrition, found that the risk of having a preterm birth for those who consistently eat a poor diet is 1.5 times that of those on a healthy diet.

"Preterm birth is a leading cause of infant disease and death and occurs in approximately one in 10 pregnancies globally," lead author of Jessica Grieger of University of Adelaide's Robinson Research Institute said in a statement.

"Anything we can do to better understand the conditions that lead to preterm birth will be important in helping to improve survival and long-term health outcomes for children," Grieger said.

In the new study, Grieger and colleagues investigated the dietary patterns of more than 300 South Australian women in a bid to better understand their eating habits before pregnancy.

They found that women who ate protein-rich foods including lean meats, fish and chicken, as well as fruit, whole grains and vegetables, had significantly lower risk of preterm birth.

"On the other hand, women who consumed mainly discretionary foods, such as takeaway, potato chips, cakes, biscuits, and other foods high in saturated fat and sugar were more likely to have babies born preterm," Grieger said.

She advised women to consume a healthy diet before as well as during pregnancy. "Diet is an important risk factor that can be modified. It is never too late to make a positive change," Grieger said. "This will help to reduce the number of neonatal deaths and improve the overall health of children."