Association between vitamin D levels in early pregnancy and gestational diabetes mellitus: A systematic review and meta-analysis.

Background: This meta-analysis aimed to pool all the available data to provide a well-powered assessment of the role of maternal Vitamin D levels in developing gestational diabetes mellitus (GDM) because already published studies evaluating this association are small in sample size and yielded conflicting findings.

Material And Methods: A systematic review and meta-analysis of observational studies was performed. We searched electronic databases (PubMed and Cochrane Central) from inception to April 2021 for published and unpublished observational studies that determined the association between the reduction of Vitamin D levels and the risk of developing GDM in pregnant women.