A systematic review and meta-analysis showed that vitamin D supplementation is beneficial to reduce maternal hyperbilirubinemia, as well as neonatal hyperbilirubinemia and the risk of hospitalization. In order to gain insights into the clinical management of gestational diabetes mellitus (GDM), researchers sought to assess the efficacy and safety of vitamin D supplementation in pregnant women with GDM and neonates.

Databases such as Wanfang, CNKI, Embase, Web of Science, Cochrane Library, PubMed, and Medline were searched by 2 authors for randomized controlled trials (RCTs) examining the effects and safety of vitamin D in GDM-affected people. The Cochrane Manual was utilized to assess the incorporated RCTs' quality. Software called RevMan 5.3 was utilized for the statistical evaluation.

The final inclusion comprised 20 RCTs with 1682 GDM subjects, 837 of whom got vitamin D supplementation. In all the GDM patients, vitamin D use raised serum 25(OH)D levels (SMD = 4.07) and high-density lipoprotein cholesterol (HDL) levels (SMD = 0.41) and decreased serum levels of low-density lipoprotein cholesterol (LDL) (SMD = -0.49), triglycerides (SMD = -0.59), and total cholesterol (SMD = -0.67). Taking vitamin D supplements decreased the likelihood of neonatal hospitalization (OR = 0.38), hyperbilirubinemia (OR = 0.38), and preterm delivery (OR = 0.37) among neonates.

There was no discernible publication bias in any of the synthesised results. Supplementing with vitamin D helps to improve GDM patients' blood lipid levels and minimizes unfavourable newborn outcomes. In high-quality future research, the duration and dose of vitamin D administration for safety must be examined further.