Vitamin D2026-06

Prevalence and Seasonal Variation in Serum 25-Hydroxyvitamin D Concentrations Among Women of Reproductive Age.

Guo Hong-Xia, Zhang Zhi-Hui, Ren Hong-Wei, Wang Hui-Yu — Clinical laboratory

Summary

This study found that a large majority (over 92%) of women of reproductive age in Beijing had vitamin D deficiency. Vitamin D levels were higher in women aged 35 and older, and showed clear seasonal changes, peaking in summer and being lowest in spring. The researchers recommend regular vitamin D checks for women planning pregnancy to ensure adequate levels.

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Abstract

BACKGROUND: This study aimed to investigate serum 25-hydroxyvitamin D [25(OH)D] concentrations among women of reproductive age, stratified by age and season, in order to provide information for vitamin D-related health strategies for this population. METHODS: A retrospective analysis was conducted on serum 25(OH)D concentrations in women of reproductive age who underwent preconception health examinations at the Physical Examination Department of Haidian District Maternal and Child Health Care Hospital between December 2022 and December 2024. Participants were stratified by age into two groups: advanced maternal age (≥ 35 years) and typical maternal age (< 35 years). Seasonal categorization included spring, summer, autumn, and winter. Intergroup comparisons were performed, and vitamin D nutritional status was classified based on established thresholds. RESULTS: A total of 2,325 women were included in the study. The mean serum 25(OH)D concentration was 34.45 ± 11.07 nmol/L. Vitamin D deficiency was observed in 92.47% of participants, insufficiency in 6.24%, and sufficiency in only 1.29%. Participants in the advanced maternal age group demonstrated significantly higher serum 25(OH)D concentrations compared to those in the normal maternal age group (p < 0.05). Seasonal variation in serum 25(OH)D concentrations was observed, with the highest levels recorded during summer and the lowest in spring. Concentrations in summer and autumn were significantly higher than those in winter and spring (p < 0.05); however, no significant differences were found between summer and autumn or between winter and spring (p > 0.05). CONCLUSIONS: A high prevalence of vitamin D deficiency was observed among women of reproductive age in Haidian District, Beijing, with significant variations by age and season. Routine assessment of serum 25(OH)D concentrations is recommended for women planning pregnancy to facilitate timely and appropriate vitamin D supplementation strategies.

View on PubMed →DOI: 10.7754/Clin.Lab.2025.250606