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

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

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. Logistic regression was used to analyze the OR value of preterm birth under different maternal dietary zinc levels.

The detection rate of preterm birth was 10.0%, of which 81.8% were moderate preterm, 18.3% were very preterm, 33.2% were medically indicated preterm and 66.8% were spontaneous preterm birth. After adjusting for general conditions such as maternal age, education level, and history of preterm birth, compared with the group with the highest zinc intake before and during pregnancy, those with low zinc intake before or during pregnancy had a significantly higher risk of moderate, very, and spontaneous preterm birth. After further controlled of folic acid and fiber intake during pregnancy, compared with the group with the highest zinc intake before and during pregnancy, the risk of very preterm birth(OR=2.04, 95%CI 1.07-3.90) and spontaneous preterm birth(OR=1.38, 95%CI 1.01-1.88) was significantly increased in those with the lowest zinc intake during the third trimester. For pregnant women aged≥30 years(OR=1.55, 95%CI 1.12-2.13) and normal or less normal weight gain during pregnancy(OR=1.51, 95%CI 1.15-1.97), insufficient zinc intake was significantly associated with preterm birth.

Maternal low dietary zinc intake during the third trimester was associated with very premature and spontaneous preterm birth.