Yue CY, Gao JP, Zhang CY, et al. - Researchers examined if there is a correlation between serum vitamin D deficiency before gestational 20 weeks and an increased risk of preeclampsia. In this study, the serum levels of 25(OH)D before gestational 20 weeks were investigated in 7,976 enrolled pregnant women between January 2017 and July 2019 at the Obstetrics & Gynecology Hospital of Fudan University. Findings suggest that vitamin D deficiency before gestational 20 weeks is correlated with an increased risk for preeclampsia.