[Association between dietary supplementation during pregnancy and low birth weight: a prospective study]

Objective: To explore the association between dietary supplementation during pregnancy and low birth weight. Methods: 11 311 pregnant women who had regularly visited outpatient gynecology clinic of Wuhan Women and Children Medical Center with intention to delivery in the hospital were recruited in the cohort between September 2012 and October 2014. Social-demographic characteristics of pregnant women and spouses, dietary supplementation during pregnancy, pre-pregnancy body mass index (BMI), exercise in the third trimester, work during pregnancy, pregnancy complications and related pregnancy information were collected through self-designed questionnaires, maternal health manuals and medical records. Birth weight of the newborns was measured. Non-conditional multivariate logistic regression analysis was used to determine the correlation between dietary supplementation and low birth weight. Results: 11 311 pregnant women were (28.21±3.70) years old, and they gave birth to 477 low birth weight newborns (4.2%). Iron supplementation during the whole period of pregnancy (OR (95%CI): 0.60 (0.43-0.63)) and folic acid supplementation during the early pregnancy (OR (95%CI): 0.74 (0.60-0.90)) were negatively associated with low birth weight. Conclusion: Supplementation of iron during the whole period of pregnancy and folic acid during the early pregnancy would reduce the risk of low birth weight.