A decade-long assessment reveals persistent vitamin D deficiency and its associated factors in early-pregnant women from northern China (2016–2025)
Background Large-scale data on vitamin D status in early-pregnant women in high-risk Northern China are scarce. This study evaluated the decadal trends (2016–2025) and associated factors of serum 25(OH)D levels in this population in Shanxi Province. Methods This retrospective cohort included 20,693 early-pregnant women...