Nutrition/Obesity
Examining dietary changes across pre-, post- and pregnancy time periods in the Nurses’ Health Study 3 Kristen Lyall* Kristen Lyall Juliette Rando Jaime Hart Loni Tabb Marc Weisskopf Heather E. Volk Jorge Chavarro
Background: Prior work has documented the reproducibility of dietary intake captured by Food Frequency Questionnaires (FFQ), but data across the pre-, post-, and pregnancy periods, which may help guide longitudinal studies and inform practice, are lacking.
Methods: Using validated semi-quantitative FFQs collected pre, during, and post-pregnancy from the Nurses’ Health Study 3 (NHS3), a prospective cohort of registered nurses in the US and Canada, we evaluated group-level mean nutrient and food group intake across these times. Correlation coefficients were calculated to assess agreement and compare to previously reported metrics.
Results: 2,757 participants had FFQs at all 3 time points, collected approximately 3 years before and after pregnancy (SD=1.5yrs). Mean intake of most factors increased during pregnancy relative to other time points, and was similar in pre- and post- periods, with the notable exceptions of decreases in alcohol and caffeine during pregnancy (mean 0.2gm/day and 66mg/day). The most substantial nutrient increases during pregnancy were for folate and iron (Figure 1; increases of 66% and 61% from pre-pregnancy, respectively; folate exceeded recommended levels: mean DFE= 2321mcg/day, SD=885). Servings/day of food groups changed little over time periods, with the exception of vegetables and dairy, which decreased and increased respectively during pregnancy by approximately ½ serving/day. Correlations across times were comparable to lower (0.2-0.5 for most nutrients and foods; .1 for folate, iron and zinc) than previously-published metrics in other populations not across pregnancy.
Conclusions: Expected changes in dietary intake were observed during pregnancy relative to pre- and post-pregnancy periods in this large national sample of women. Stability in food group intakes over time was supported across these childbearing periods, but higher than recommended average levels of certain nutrients such as folate may warrant further consideration.
