Zhang et al. performed a systematic review and found that variants in seven genes are significantly associated with GDM, including TCF7L2, GCK, KCNJ11, CDKAL1, IGF2BP2, MTNR1B, and IRS1, with the first six genes related to insulin secretion and IRS1 related to insulin resistance [35]. This evidence concerns the gene TCF7L2 and Insulin resistance.