Fruit and vegetable consumption before and during pregnancy and birth weight of new-borns in Japan: the Tohoku medical megabank project birth and three-generation cohort study

Background Associations of fruit and vegetable consumption before and during pregnancy with birth weight of new-borns and the risk of low birth weight (LBW) remain unclear. Methods Between July 2013 and March 2017, we recruited 23,406 pregnant women in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study). Fruit and vegetable consumption before and during pregnancy was calculated using food frequency questionnaires. Information regarding birth weight was obtained from medical records, and LBW was defined as < 2500 g. We used a multivariable linear regression model and a multivariate logistic regression model to assess associations between fruit and vegetable consumption and birth weight/risk of LBW. Results In total, 17,610 women were included in the analysis. Mean birth weight was 3061.8 +/- 354.1 g, and 5.4% of the new-borns had LBW. Compared to women in the lowest quartile of fruit consumption between pre- and early pregnancy, women in the highest quartile had heavier new-borns (beta = 49.4; 95% CI: 34.1-64.7) and lower risk of LBW (OR: 0.79; 95% CI: 0.65-0.95). Women in the highest quartile of fruit consumption from early to mid-pregnancy also had heavier new-borns (beta = 32.3; 95% CI: 17.1-47.6), and they tended to have lower risk of LBW (OR: 0.83; 95% CI: 0.69-1.01). Results of analysing the association between changes in fruit consumption from pre- to mid-pregnancy and birth outcomes revealed that women with continuous high fruit consumption from pre- to mid-pregnancy had heavier new-borns (beta = 37.6; 95% CI: 25.0-50.3), but they did not have lower risk of LBW (OR: 0.90; 95% CI: 0.77-1.06). Associations involving vegetable consumption and birth weight/risk of LBW were not observed. Conclusions Fruit consumption before and during pregnancy was positively associated with birth weight of new-borns and negatively associated with risk of LBW.