Assessment of Environmental Risk Factors for Gestational Diabetes Mellitus: A Ten-Year Systematic Review and Meta-Analysis

Background/Objectives: It is estimated that gestational diabetes mellitus (GDM) affects approximately 14% of pregnant women. This is due to the inability of the body to produce enough insulin for gestation. With greater appearance during the second and third trimesters, GDM has a multifactorial cause including hypertension, cardiovascular issues (CVD), family history both or either type two diabetes mellitus (T2DM) or GDM, obesity, advanced maternal age, and polycystic ovarian syndrome (PCOS). However, it has been suggested that except for genetic predisposition, environmental factors can increase the risk of GDM development to a great extent. The aim of this systematic review and meta-analysis is the examination of different environmental contributors that play a significant role in the development of GDM. Methods: The databases used were PubMed and ScienceDirect. The inclusion criteria were a 10-year duration (2014–2024), English language, research articles, and only humans included. Afterwards, tables were created to summarize the most important information from each article. Forest and funnel plots were created to assess the possibility of a greatly significant difference between each environmental contributor. Results: Initially, 9361 articles were found. After the automation tools were applied, 706 were left. The total number of articles used in the study after the screening process was 26. Through the systematic review analysis, the following risk factors were stated to play a contributing role with GDM: extreme temperatures (both high and low), organophosphorus flame retardants (OFRs), bisphenol A (BPA), selenium (Se), metallic elements, urinary antimony (Sb), trace elements, thiamine and riboflavin, and fine particulate matter PM_2.5. Conclusions: Through this meta-analysis, it can be concluded that there is statistical significance for fine particulate matter PM_2.5, especially in the first (p < 0.001) and second (p < 0.001) trimesters, proving the acknowledged connection between PM_2.5 and GDM pathogenesis during pregnancy. Apart from that, fetal sex can play an important role in the development of GDM, as there is the greatest risk in males (p < 0.001), whereas no correlation between maternal smoking habit and bisphenol A with GDM was found. In conclusion, it can be stated that environmental factors can have a great impact on the development of GDM during the gestational period, but more studies must be carried out to reinforce our outcomes.