Longitudinal assessment of micronutrient intake during early and mid-pregnancy using 24-hour dietary recall and food frequency questionnaire methods in north Karnataka, India

Background: Accurate assessment of dietary micronutrient intake during pregnancy is essential for evaluating nutritional adequacy and planning interventions. Longitudinal assessment provides evidence to guide maternal nutrition recommendations.Objective: To assess longitudinal changes in dietary intake of iron, folic acid, and vitamin C among pregnant women compared to the Recommended Dietary Allowances (RDA) proposed by ICMR–National Institute of Nutrition.Materials and Methods: A longitudinal study was conducted among 128 pregnant women attending antenatal care at a tertiary hospital in North Karnataka (June 2023–September 2024). Dietary intake was assessed at early and mid-pregnancy using a 24-hour dietary recall (24HDR) and a validated semi-quantitative Food Frequency Questionnaire (FFQ). Changes in mean nutrient intakes between and within the methods were examined using Wilcoxon tests (p < 0.05).Results: Mean intakes of iron, folic acid, and vitamin C intakes were consistently higher when assessed using the 24HDR compared to the FFQ in both early and mid-pregnancy (all p < 0.01). From early to mid-pregnancy, folic acid intake increased significantly using both methods 24HDR (mean difference: +26.3 µg/day; 95% CI: 13.6 to 39.0; p < 0.001) and FFQ (+7.3 µg/day; 95% CI: 2.1 to 12.5; p = 0.007). Vitamin C showed a significant increase only with the 24HDR (+12.9 mg/day; 95% CI: 3.7 to 22.2; p = 0.007). No significant changes were observed in iron intake with either method (24HDR: –1.37 mg; 95% CI: –4.53 to 1.79; p = 0.39; FFQ: –0.11 mg; 95% CI: –0.71 to 0.49; p = 0.71). Across both methods and time points, mean dietary intakes remained below the recommended daily allowance for pregnant women.Conclusion: Combining short-term (24HDR) and habitual (FFQ) methods improves the precision of micronutrient intake assessment in pregnancy and supports the need for strengthened nutrition counselling, routine dietary monitoring, and personalised supplementation. Findings should be interpreted in light of self-reported dietary intake and the exclusion of supplement-derived nutrients.