Maternal Dietary Patterns during the Second Trimester Are Associated with Preterm Birth

Background: Preterm birth is one of the leading causes of neonatal morbidity in the United States. Despite decades of research, the etiology is largely unknown. Objective: The purpose of our study was to examine the association between maternal dietary patterns during pregnancy and preterm birth. Methods: This prospective cohort study used data from the PIN (Pregnancy, Infection, and Nutrition) study (n = 3143). Dietary intake was assessed at 26-29 wk of gestation by using a food-frequency questionnaire, and patterns were derived by using factor analysis and the Dietary Approaches to Stop Hypertension (DASH) diet. Associations between dietary patterns and preterm birth were assessed by logistic regression. Results: Four dietary patterns were identified from the factor analysis characterized by high intakes of the following: 11 fruits, vegetables, low-fat dairy, high-fiber and fortified cereals, nonfried chicken and fish, and wheat bread; 21 beans, corn, French fries, hamburgers or cheeseburgers, white potatoes, fried chicken, mixed dishes, and ice cream; 3) collard greens, coleslaw or cabbage, red and processed meats, cornbread or hushpuppies, whole milk, and vitamin C-rich drinks; and 4) shellfish, pizza, salty snacks, and refined grains. Increased odds of preterm birth were found for a diet characterized by a high consumption of collard greens, coleslaw or cabbage, red meats, fried chicken and fish, processed meats, cornbread or hushpuppies, eggs or egg biscuits, gravy, whole milk, and vitamin C-rich drinks such as Kool-Aid (Kraft Foods) and Hi-C (Minute Maid Co.) (adjusted OR for quartile 4 vs. quartile 1: 1.55; 95% Cl: 1.07, 2.24). Greater adherence to the DASH diet was associated with decreased odds of preterm birth compared with women in the lowest quartile (adjusted OR for quartile 4 vs. quartile 1: 0.59; 95% Cl: 0.40, 0.85). Conclusions: Diet quality during pregnancy is associated with preterm birth; thus, preconceptional and early prenatal dietary counseling promoting healthy dietary intake could improve pregnancy outcomes.