Changes in dietary intake from the first to the second trimester of pregnancy

Maternal diet may influence outcomes of pregnancy and childhood. Diet in the first trimester may be more important to development and differentiation of various organs, whereas diet later in pregnancy may be important for overall fetal growth as well as for brain development. To our knowledge, no studies have examined individual-level changes in food and nutrient intake from the 1st to 2nd trimester of pregnancy. The objective of this study was to examine changes in dietary intake from the 1st to 2nd trimester of pregnancy. As part of the ongoing US prospective cohort study, Project Viva, we studied 1543 women who completed food-frequency questionnaires that assessed dietary intakes during the 1st and 2nd trimester of pregnancy. For both foods and energy-adjusted nutrients, we examined changes in dietary intake from 1st to 2nd trimester. Reported mean energy intake was similar for the 1st (2046 kcal) and 2nd (2137 kcal) trimesters. Foods and energy-adjusted nutrients from foods whose overall mean intakes increased more than 5% from 1st to 2nd trimester were skim or 1% dairy foods (22%), whole-fat dairy foods (15%), red and processed meat (11%), saturated fat (6%) and vitamin D (7%). Intake of caffeinated beverages (-30%) and alcoholic beverages (-88%) decreased more than 5%. Because mean multivitamin intake increased by 35% from the 1st to 2nd trimester, total micronutrient intake increased appreciably more than micronutrient intake from foods only. Correlations across trimesters ranged from 0.32 for vitamin B12 to 0.68 for fruit and vegetables. In conclusion, for many outcomes of pregnancy and childhood, the incremental information obtained from assessing complete diet in both early and late pregnancy may not outweigh the burden to participants and investigators. However, investigators should assess caffeine, alcohol, and vitamin and supplement use in both the 1st and 2nd trimester, and consider doing so for foods and nutrients for which trimester-specific hypotheses are well substantiated.