Several randomized controlled trials (RCT) investigated antenatal dietary supplements’ effect on gestational diabetes mellitus patients’ fasting plasma glucose levels, glycated hemoglobin levels, homeostasis model assessment of- insulin resistance and β-cell function, quantitative insulin sensitivity check index for glucose, high-, low-, and very-low-density lipoprotein cholesterol levels, total cholesterol levels, triglyceride levels, and triglyceride to high-density lipoprotein ratio. This evidence concerns the gene INS and gestational diabetes.