RARRES2 and gestational diabetes: The results showed that there was no significant difference between GDM patients and normal controls in circulating apelin (SMD = 0.43, 95% CI − 0.40 to 1.26, P = 0.31) and chemerin (SMD = 0.77, 95% CI − 0.07 to 1.61, P = 0.07) levels.