Evidence is inconsistent concerning the effect of macronutrient dietary composition (carbohydrate [CHO], protein and fat) during pregnancy on adverse birth outcomes( Reference Moore, Davies and Willson 1 , Reference Chong, Chia and Colega 2 , Reference Lagiou, Tamimi and Mucci 3 ). The aim of our study was to explore whether maternal dietary macronutrient intake in the first trimester was associated with offspring birthweight.
A prospective cohort( Reference Boylan, Cade and Kirk 4 ) of 1,196 pregnant women in Leeds, UK provided a 24 hour dietary recall. Additional information on alcohol intake and smoking status was collected. Multiple linear regression models analysed the association between maternal macronutrient dietary intake in the first trimester and birthweight. Models were adjusted for confounders including ethnicity, parity, gestational age at delivery, maternal height, weight and neonatal gender, and mutually adjusted for energy contributing macronutrients (Model 1). Model 2 was additionally adjusted for alcohol intake and smoking status.
=Mutually adjusted for other energy contributing macronutrients aAdjusted for maternal weight, height, ethnicity, parity, gestational age at delivery, sex of baby bAdditional adjustment for average alcohol intake and smoking status
Results showed that each additional 10 g/day CHO consumption in the first trimester was associated with an increase of 4 g (95 % CI 1 to 7; P = 0·003) in birthweight. Conversely, each additional 10 g/day fat consumption was associated with a decrease of 8 g (95 % CI 0·3 to 16; P = 0·04) in birthweight. There was no evidence of an association between protein intake and birthweight after adjusting for alcohol intake and smoking habits.
Fat and CHO consumption in the first trimester could play a role in optimising birthweight. We recommend an appropriate balance of carbohydrate and fat intake during pregnancy.