[Development of a quantitative food frequency questionnaire for pregnant women attending primary care in Ribeirão Preto, São Paulo State, Brazil].

The aim of this study was to design a food frequency questionnaire for pregnant women attending primary care under the Unified National Health System in Ribeirão Preto, São Paulo State, Brazil. A 24-hour food recall was obtained from 150 pregnant women, 50 in each trimester of pregnancy (age 18-35 years). A second food recall was obtained from 90 women, 30 in each trimester of pregnancy, from 7 to 15 days after the first dietary assessment. An 85-item questionnaire was developed with stepwise multiple linear regression models, based on the contribution of each food to inter-individual variation of energy and 28 target nutrients, which accounted for 74.2 to 98.8% of the selected nutrients. Portion sizes were determined according to percentiles 25, 50, 75, and 100 for each food item intake. To our knowledge, this is the first food frequency questionnaire designed for Brazilian pregnant women.