Association Between Maternal Vitamin K2 Levels in Late Pregnancy and Newborn Bone Metabolism

We aimed to explore maternal vitamin K2 levels in late pregnancy and their association with neonatal bone metabolism markers. This study included 197 pregnant women and their matched newborns. Blood samples were collected from the mothers 1–2 days before delivery and from the umbilical cord immediately after birth. Serum vitamin K2 and 25-hydroxyvitamin D (25-OHD) levels were measured using liquid chromatography–tandem mass spectrometry. Maternal vitamin K2 levels were categorized into vitamin K2 deficiency (< 0.1 ng/mL) and normal (0.1–0.86 ng/mL) groups. Maternal vitamin K2 deficiency prevalence was 38.6%. Spearman's correlation analysis demonstrated a significant association between maternal vitamin K2 and newborn 25-OHD levels (r = 0.368, p < 0.001). Maternal osteocalcin (OC), newborn OC, and newborn parathyroid hormone levels in the vitamin K2 deficiency group were significantly higher than those in the normal group. Univariate and multivariate logistic regression analysis indicated that maternal vitamin K2 and newborn calcium levels were independent risk factors for neonatal 25-OHD insufficiency. In conclusion, maternal vitamin K2 deficiency is prevalent during late pregnancy and may adversely affect both maternal and neonatal bone metabolism, highlighting the importance of vitamin K2 supplementation during pregnancy.