Objective：To validate a semi-quantitative fbod-frequency questionnaire(FFQ)for evaluating nutrient intake among pregnant women in rural China．Design：Longitudinal validation study with interview administrated FFQs at start of third trimester(FFQ1)and repeated three months later prior to delivery(FFQ2)，with six repeated 24-hour recalls in between．Setting：Two rural counties in Shaanxi province，western China．Subjects：125 women at 23 to 26 weeks gestation recruited from June to September 2004.Results：Pearson correlation coefficients for crude nutrients assessed by FFQ1 and FFQ2 ranged from 0.3l for thiamin to 0.61 for fat(mean of all nutrients 0.46)．Pearson correlation coeffcients for nutrients estimated by FFQ2 and 24-hour recalIs ranged from 0.53 for cholesterol to 0.70 for α-vitamin E and potassium(mean of all nutrients 0.62)．Energy-adjustment lowered most coefficients．De-attenuated&an．adjusted coefficients ranged from 0.58 for cholesterol to 0.77 for α-vitamin E(mean of all nutrients 0.69)．Bland-Altman plots revealed significant relationships between the difference and the average of the two methods with larger differences at higher average intakes．On average，74﹪of participants were classified into the same or adjacent nutrient intake quintiles，while 1﹪were grossly misclassified to opposite quintiles．The same four food groups accounted for 80﹪0f total food energy intake in both methods．Conclusions：This FFQ has adequate reproducibility and validity for most nutrients and is suitable for use to assess dietary intake in pregnant women inrural China．
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