Dietary Patterns and Birth Weight-a Review.

Being born with low birth weight (LBW) is recognized as a disadvantage due to risk of early growth retardation, fast catch up growth, infectious disease, developmental delay, and death during infancy and childhood, as well as development of obesity and non-communicable diseases (NCDs) later in life. LBW is an indicator of fetal response to a limiting intrauterine environment, which may imply developmental changes in organs and tissue. Numerous studies have explored the effect of maternal intake of various nutrients and specific food items on birth weight (BW). Taking into account that people have diets consisting of many different food items, extraction of dietary patterns has emerged as a common way to describe diets and explore the effects on health outcomes. The present article aims to review studies investigating the associations between dietary patterns derived from analysis and BW, or being small for gestational age (SGA). A PubMed search was conducted with the Mesh terms "pregnancy" OR "fetal growth retardation" OR "fetal development" OR "infant, small for gestational age" OR "birth weight" OR "infant, birth weight, low" AND "diet" OR "food habits". Final number of articles included was seven, all which assessed diet by use of food frequency questionnaire (FFQ). Five studies explored dietary patterns using principal component analyses (PCA), while one study used cluster analyses and one study logistic regression. The studies reported between one and seven dietary patterns. Those patterns positively associated with BW were labeled "nutrient dense", "protein rich", "health conscious", and "Mediterranean". Those negatively associated with BW were labeled "Western", "processed", "vegetarian", "transitional", and "wheat products". The dietary patterns "Western" and "wheat products" were also associated with higher risk of SGA babies, whereas a "traditional" pattern in New Zealand was inversely associated with having a SGA baby. The dietary patterns associated with higher BW or lower risk of having babies born SGA were named differently, but had similar characteristics across studies, most importantly high intakes of fruits, vegetables and dairy foods. Dietary patterns associated with lower BW or higher risk for giving birth to a SGA baby were characterized by high intakes of processed and high fat meat products, sugar, confectionaries, sweets, soft drinks, and unspecified or refined grains. All studies in this review were performed in high-income countries. More research is warranted to explore such associations in low and middle income countries, where underweight babies are a major health challenge many places. Furthermore, results from studies on associations between diet and BW need to be translated into practical advice for pregnant women, especially women at high risk of giving birth to babies with LBW.