The Effects of Vitamin D Supplementation on Metabolic Profiles and Pregnancy Outcomes in Patients with Gestational Diabetes:a Systematic Review

Although several studies have investigated the effect of vitamin D supplementation on glucose homeostasis parameters and lipid profiles, and pregnancy outcomes in gestational diabetes (GDM), findings are inconsistent. GDM is defined as glucose intolerance and insulin resistance with onset or recognition during pregnancy. GDM affects approximately 1-14 % of pregnancies depending on the diagnostic criteria, gestational age and characteristics of the study population. Poor maternal glycemic control will result in maternal short- and long-term adverse outcomes, including subsequent development of type 2 diabetes mellitus (T2DM), gestational hypertension, pre-eclampsia, cesarean delivery, macrosomia, birth defects and subsequent adolescent and childhood overweight. Furthermore, lipid disorders in GDM are associated with T2DM, endothelial dysfunction, atherosclerosis, and intrauterine growth retardation.Recently, increasing effort has been devoted to identify dietary factors that can delay the progression of GDM. While the classic essential nutrients have been widely studied in this regard, there is also great interest in the evaluation of vitamin D. Women with GDM might be more likely to have vitamin D deficiency compared with women with normal glucose tolerance. This status may occur due to insufficient intake of vitamin D, ambient temperature and physical activity, which in turn may affect maternal physiology, and fetal and placental development at the cellular level and contribute to the development of GDM. Thus, it is reasonable to postulate that, vitamin D supplementation may have beneficial effects on diabetes biomarkers including fasting insulin and blood glucose, insulin resistance, as well as lipid profiles and pregnancy outcomes. Few studies have reported that vitamin D administration among GDM subjects resulted in improved glucose homeostasis parameters and few lipid profiles, and pregnancy outcomes. However, others have demonstrated not only no significant effect of vitamin D supplementation on glucose metabolism and lipid fractions, and pregnancy outcomes. These discrepancies might be related to the differences of studies in terms of population and duration of intervention. Despite several randomized controlled trials (RCTs). This systematic review was conducted to summarize the available literature to evaluate the effect of vitamin D supplementation on metabolic profiles and pregnancy outcomes in GDM subjects.

Keywords:

Vitamin D , glucose homeostasis , lipid profiles