Dietary Intake Relative to Japanese Reference Values During Late Pregnancy Among Japanese Women Undergoing Scheduled Cesarean Delivery: A Single-Center Cross-Sectional Study

Background: Maternal nutrition during late pregnancy is crucial for maternal and fetal health.This study descriptively evaluated dietary intake relative to the Dietary Reference Intakes for Japanese (2025 edition) among Japanese women admitted for scheduled cesarean delivery at a single center.Methods: This single-center cross-sectional study enrolled Japanese women admitted to Kasukabe Medical Center for scheduled cesarean delivery between October 2022 and April 2024.Dietary intake during the preceding month was assessed upon admission using a validated self-administered Diet History Questionnaire.Nutrient intakes were expressed relative to the corresponding values in the Dietary Reference Intakes for Japanese (2025 edition).These reference values were used as descriptive benchmarks and not as diagnostic cutoffs for individual nutritional adequacy.Gestational weight gain was assessed using the Japanese Obstetric Guidelines.The analyses were descriptive.Data on dietary supplement use were not systematically collected.Results: Of the 58 enrolled women, one (1.7%) was excluded because of incomplete questionnaire data, and 57 (98.3%) were included in the final analysis.The mean energy intake was 1,866 ± 573 kcal/day, and the mean intake relative to the individually estimated energy requirement was 89.6%.The mean intake as a percentage of the reference value was lowest for iron (44.9%), vitamin D (49.3%), and folate (55.8%).The numbers of participants reaching the corresponding reference values were none (0%) for iron, two (3.5%) each for vitamin D and folate, four (7.0%) for vitamin B6, three (5.3%) for magnesium, and four (7.0%) for zinc.The mean sodium intake was 3,961 ± 1,410 mg/day, and only five (8.8%) participants had an intake within the dietary goal.Overall, 32 (56.1%) participants reached at least the lower limit of the recommended gestational weight gain.Conclusions: In this selected single-center cohort of Japanese women undergoing scheduled cesarean delivery, dietary intakes of several micronutrients were low relative to the Japanese reference values, whereas sodium intake frequently exceeded the dietary goal.These descriptive findings may not be generalizable to all pregnant Japanese women and should not be interpreted as evidence of inadequate total nutrient intake or biochemical nutrient deficiency because dietary supplement use and biochemical nutrient status were not assessed.Larger, more representative multicenter studies that systematically assess supplement use are needed.