Associations of consumption of fruits and vegetables during pregnancy with infant birth weight or small for gestational age births: a systematic review of the literature.

Maternal nutrition is recognized as one of the determinants of fetal growth. Consumption of fruits and vegetables is promoted as part of a healthful diet; however, intakes are typically lower than recommended levels. The purpose of this study was to systematically review results from studies examining the relationship between maternal consumption of fruits and vegetables during pregnancy with infant birth weight or risk for delivering a small for gestational age baby. A comprehensive search of PubMed and EMBASE was conducted and abstracts were screened using predefined criteria. Eleven relevant studies were identified and systematically reviewed, including six prospective cohort studies, three retrospective cohort studies, and two case-control studies. Seven studies were conducted in cohorts from highly developed countries. One prospective study from a highly developed area reported increased risk for small for gestational age birth by women with low vegetable intakes (odds ratio 3.1; 95% confidence interval 1.4-6.9; P=0.01); another large prospective study reported a 10.4 g increase in birth weight per quintile increase in fruit intake (95% confidence interval 6.9-3.9; P<0.0001) and increases of 8.4 or 7.7 g per quintile intake of fruits and vegetables (combined) or fruits, vegetables, and juice (combined), respectively. One retrospective study reported an association between low fruit intake and birth weight. In less developed countries, increased vegetable or fruit intake was associated with increased birth weight in two prospective studies. Overall, limited inconclusive evidence of a protective effect of increased consumption of vegetables and risk for small for gestational age birth, and increased consumption of fruits and vegetables and increased birth weight among women from highly developed countries was identified. Among women in less developed countries, limited inconclusive evidence suggests that increased consumption of vegetables or fruits may be associated with higher infant birth weight. The available evidence supports maternal consumption of a variety of fruits and vegetables as part of a balanced diet throughout pregnancy.