Associations between maternal dietary patterns and infant birth weight, small and large for gestational age in the Norwegian Mother and Child Cohort Study

BACKGROUND/OBJECTIVES: To assess whether quality of maternal diet affects birth weight and the risk of small for gestational age (SGA) and/or large for gestational age (LGA) babies. SUBJECTS/METHODS: This study is based on the Norwegian Mother and Child Cohort Study (MoBa) and includes 65,904 pregnant women who answered a validated food frequency questionnaire at mid-pregnancy. Three maternal dietary patterns were extracted based on characteristics of food items in each pattern. From these we created four non-overlapping groups: “high prudent,” “high Western,” “high traditional,” and “mixed”. We obtained information about birth weight from the Norwegian Medical Birth Registry and calculated birth weight z-scores, SGA, and LGA according to an ultrasound-based, population-based, and a customized growth standards. Associations were studied by linear and multiple logistic regression. RESULTS: Compared to the high Western group, the high prudent group was associated with lower birth weight (β(ultrasound) z-scores −0.041 (95% confidence interval (CI): −0.068, −0.013)) and the high traditional group with higher birth weight (β(ultrasound) 0.067 (95% CI: 0.040, 0.094)) for all three growth standards. The high prudent pattern was associated with increased SGA risk (SGA(ultrasound) odds ratio (OR) 1.25 (95% CI: 1.02, 1.54)) and decreased LGA risk (LGA(population) OR 0.84 (95% CI: 0.75, 0.94)), while the high traditional group on the contrary was associated with decreased SGA (SGA(customized) OR 0.92 (95% CI: 0.84, 0.99)) and increased LGA risk (LGA(population) OR 1.12 (95% CI: 1.02, 1.24)). CONCLUSIONS: Food quality was associated with birth weight in this well-nourished Norwegian population. Food quality may affect a woman’s risk of giving birth to a SGA or LGA baby.