Severe vitamin D deficiency in the first trimester is associated with placental inflammation in high-risk singleton pregnancy

Summary Background & aims Vitamin D deficiency during pregnancy is a worldwide epidemic. This study aimed to identify whether vitamin D deficiency in early pregnancy is associated with placental inflammation in high-risk pregnancy. Methods This study comprised 23,396 women who provided serum samples in the first trimester for vitamin D analysis from January 2015 to December 2016. Among them, 2648 women with high-risk pregnancy underwent placental pathologic examination. Women were divided into placental inflammation positive (PIP) and placental inflammation negative (PIN) groups based on placental pathology. Multivariate logistic regression was used to evaluate the relationship between vitamin D levels and placental inflammation. Results We found that severe vitamin D deficiency in early pregnancy was associated with placental inflammation. Maternal vitamin D levels were significantly lower in the PIP group than those in the PIN group (P = 0.025). Compared with the highest quartile of vitamin D levels, risk for placental inflammation was significantly higher in women with extremely low vitamin D levels ( Conclusions Severe vitamin D deficiency in the first trimester is a risk factor for placental inflammation in high-risk pregnancy.