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Validation Information: FFQ (Pregnant Women)

Mejía-Rodríguez 2012

Validation of a Novel Method for Retrospectively Estimating Nutrient Intake During Pregnancy Using a Semi-Quantitative Food Frequency Questionnaire

Case control studies evaluating the relationship between dietary intake of specific nutrients and risk of congenital, neonatal or early childhood disease require the ability to rank relative maternal dietary intake during pregnancy. Such studies are limited by the lack of validated instruments for assessing gestational dietary intake several years post-partum. This study aims to validate a semiquantitative interview-administered food frequency questionnaire (FFQ) for retrospectively estimating nutrient intake at two critical time points during pregnancy. The FFQ was administered to women (N = 84), who 4–6 years earlier had participated in a prospective study to evaluate dietary intake during pregnancy. The FFQ queried participants about intake during the previous month (FFQ-month). This was then used as a reference point to estimate consumption by trimester (FFQ-pregnancy). The resulting data were compared to data collected during the original study from two 24-h recalls (24 h-original) using Spearman correlation and Wilcoxon sign-rank-test. Total energy intake as estimated by the retrospective and original instruments did not differ and was only weakly correlated in the trimesters (1st and 3rd) as a whole (r = 0.18–32), though more strongly correlated when restricted to the first half of the 1st trimester (r = 0.32) and later half of the 3rd trimester (r = 0.87). After energy adjustment, correlation between the 24hR-original and FFQ-pregnancy in the 3rd trimester were r = 0.25 (P < 0.05) for dietary intake of vitamin A, and r = 0.26 (P < 0.05) for folate, and r = 0.23–0.77 (P < 0.005) for folate, and vitamins A, B6 and B12 in the 1st and 3rd trimester after including vitamin supplement intake. The FFQ-pregnancy provides a consistent estimate of maternal intake of key micronutrients during pregnancy and permits accurate ranking of intake 4–6 years post-partum.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Energy, Micronutrient
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
1 month
Portion Size Measures info
Portion sizes for each food item were based on the mean portion size reported in ENN99, those not reported in EN99 were given portion sizes based on averaging the measurements of 10 servings of a given food.
Reporting Method info
Retrospective; Usual
Format info
Supplements Measured
Administration Method info
Interviewer adminstered

Study Information

Study Location
Morelos, Mexico
Associated Nutrient Database
Food composition table, compiled at the National Institute of Public Health, based on the USDA and INCAP Food Composition Tables using software developed at the INSP.
Comparator Validated Against
24hr Recall


Sample Size
84 (First trimester), 84 (Third trimester)
Adolescents, Adults (First trimester of pregnancy, 15-37 years), Adolescents, Adults (Third trimester of pregnancy, 15-37 years)
Age of Population

Age Range: 15-37 years; Mean (SD): 23.1 (4.9) years

Female Only
Other Notable Characteristics
All participants had participated in a prospective study to evaluate dietary intake during pregnancy, 4-6 years earlier. Results shown are for the FFQ-month only and do not include supplements.

Total number of nutrients validated: 4 info

Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Energy
  • Macronutrients: 0
  • Micronutrients: 4
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
24hr Recall Adolescents, Adults (First trimester of pregnancy, 15-37 years) Female Only Energy (kcal) 55.2 (Median) 0.17 (S)
Folate (DFE, mcg) -61.7 (Median) -0.14 (S)
Vitamin B12 (µg) 0.89 (Median) 0.10 (S)
24hr Recall Adolescents, Adults (Third trimester of pregnancy, 15-37 years) Female Only Energy (kcal) -109.1 (Median) 0.08 (S)
Folate (DFE, mcg) -94.5 (Median) 0.26 (S)
Vitamin B12 (µg) 0.9 (Median) 0.10 (S)

Some results have been calculated using statistical techniques based on the published data.

For further information on statistical terms click on Statistical tests used in validation studies

All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.

  • # Adjusted
  • † Energy adjusted.
  • ‡ For loge-transformed, energy-adjusted nutrient intakes.
  • ^ Adjacent included.
  • ᵟ Participants provided identical responses.
  • (w) = Weighted.

Mejía-Rodríguez F, Orjuela MA, García-Guerra A, Quezada-Sanchez AD, Neufeld LM. Validation of a novel method for retrospectively estimating nutrient intake during pregnancy using a semi-quantitative food frequency questionnaire. Maternal and child health journal. 2012 Oct 1;16(7):1468-83.