, tumor necrosis factor-α (TNF-α) and interleukin-6, as well as the newly discovered resistin, visfatin and apelin [11, 12] . The roles of adipocytokines and elevated lipid concentrations in pregnancy have also been associated with the changes in insulin sensitivity in nonpregnant women [13] as well as in pregnant women [14] . Evidence suggests that one or more of these adipokines might impair insulin signaling and cause insulin resistance [12] . Specifically, TNF-α has a potential role in decreasing insulin sensitivity [15] .