The median amniotic fluid concentration of resistin was significantly higher in pregnancies at term not in labor than in those in the mid-trimester (23.6 ng/mL, IQR 16.3-31.1 vs. 10 ng/mL, IQR 6.2-15.3; p<0.001). In contrast, no significant differences were observed in the median amniotic fluid resistin concentration between women with spontaneous labor at term and those at term not in labor (28.7 ng/mL, IQR 19.3-39.4 vs. 23.6 ng/mL, IQR 16.3-31.1; p=0.07).