[Association between maternal zinc intake and preterm birth in Gansu Province in 2010-2012].

Objective: To analyze the association between maternal dietary zinc levels at different stages and preterm birth.

Methods: The subjects were from the 2010-2012 birth cohort of Maternal and Child Health Hospital of Gansu Province, and a total of 10 179 pregnant women were included in the final study. Dietary information before and during pregnancy was collected through semi-quantitative food frequency questionnaire, and daily zinc intake in each period was estimated according to the frequency of consumption and portion size of food items using the Chinese Standard Tables of Food Consumption.