Association between fruit and vegetable consumption and birth weight: a prospective study among 43,585 Danish women.

OBJECTIVE: To examine whether fruit and vegetable consumption in pregnancy is associated with birth weight in a Western population.

DESIGN: Prospective cohort study based on telephone interviews, a food frequency questionnaire (FFQ), and extractions of birth characteristics from national health registries.

SUBJECTS AND SETTING: The 43,585 Danish women from the Danish National Birth Cohort who had completed the FFQ in mid-pregnancy and on whom information about birth outcome was available. The exposures were frequency of green leafy vegetable (GLV) intake and quantified intake of fruit, fruit and vegetables, and fruit and vegetables and juice. The outcomes were birth weight and z-score for expected birth weight adjusted for sex and gestation week. Information on maternal height, weight, smoking, and other potential confounders was obtained through telephone interviews.

RESULTS: Significant associations were found for all exposures to fruit and vegetable intake with birth weight and most with z-score. The strongest association was found for fruit intake in which case birth weight increased by 10.7 g (95% CI 7.3-14.2) per quintile. All associations were stronger among lean women (BMI<20, n = 7,169), whose children's birth weight increased by 14.6 g (95% CI 6.4-22.9) per quintile increase in fruit intake. For GLV the results were more inconclusive. When adjusted for confounders, but not for energy, the association between GLV and birth weight was significant, but the same was not the case for z-score.

CONCLUSION: Fruit and vegetable consumption in pregnancy is positively associated with birth weight in well-nourished Danish women, especially among lean women.