University of Adelaide research has for the first time confirmed that women who eat a poor diet before they become pregnant are around 50% more likely to have a preterm birth than those on a healthy diet.Researchers confirmed that women who eat a poor diet before they become pregnant are around 50% more likely to have a preterm birth than those on a healthy diet. The study shows that women who consistently ate a diet high in protein and fruit prior to becoming pregnant were less likely to have a preterm birth, while those who consistently ate high fat and sugar foods, and take-out food were about 50% more likely to have a preterm birth.