Background Inadequate maternal nutrition is regarded as one of the most important indicators of fetal growth. The aim of this study was to analyze the associated risk of having a small for gestational age (SGA) infant according to the mother's dairy intake during the first half of pregnancy. Methods A prospective cohort study was performed using 1175 healthy pregnant women selected from the catchment area of Virgen de las Nieves University Hospital, Granada (Spain). SGA was defined as neonates weighing less than the 10th percentile, adjusted for gestational age. Factors associated with SGA were analyzed using logistic regression models. Population attributable fractions of SGA according to dairy intake were estimated. Results Dairy intake among women who gave birth to SGA infants was 513.9, versus 590.3 g/day for women with appropriate size for gestational age infants (P = 0.003). An increased intake of dairy products by 100 g/day during the first half of pregnancy decreased the risk of having a SGA infant by 11.0 %, aOR = 0.89 (0.83, 0.96). A dose-response gradient between dairy intake and SGA was observed. Conclusions An inadequate intake of dairy products is associated with a higher risk of SGA. Our results suggest a possible causal relation between dairy intake during pregnancy and the weight of the newborn, although we cannot discard residual confounding. These results should be further supported by properly designed studies.
Keywords: Dairy intake; Maternal nutrition; Population attributable fraction; Pregnancy; Small for gestational age.