Abstract： Objective:To investigate the expression level of p57Kip2 gene in placenta tissues of normal pregnant women and gestational diabetes mellitus(GDM)patients, we will explore the correlation between p57Kip2 gene and GDM.These results will provide a basis for p57Kip2 as an early monitoring indicator of GDM and a new therapeutic drug target.Methods:This study was a case-control study.A total of 60 pregnant women, aged(29.95±4.66)years old, ranging from 18 to 38 years old, who received the obstetrics department of Affiliated Hospital of Jining Medical College from March 2017 to December 2018.They were divided into GDM group and healthy group according to whether they had GDM or not, there were 30 GDM pregnant women and 30 healthy pregnant women.After delivery, placenta samples were taken and paraffin sections were prepared.The expression and localization of p57Kip2 protein in placenta tissues were detected by immunohistochemical streptavidin-perosidase(SP)method.The expression level of p57Kip2 mRNA in the placental tissues of GDM patients and healthy pregnant women was detected by reverse transcription polymerase chain reaction(RT-PCR).To analyze the correlation between p57Kip2 and fasting blood glucose in pregnant women and neonatal weight.Results:Immunohistochemical staining showed that p57Kip2 protein was mainly expressed in the nucleus of cytotrophoblast cells of placental tissue, but was less expressed in syncytiotrophoblast cells.The expression level of p57Kip2 protein in placental tissue of GDM pregnant women[(0.24±0.15)nmol/L]was significantly higher than that of healthy pregnant women[(0.16±0.09)nmol/L], and the difference was statistically significant( t=-2.54, P=0.013).The expression level of p57Kip2 mRNA in the placental tissues of GDM pregnant women was significantly higher than that of healthy pregnant women, and the difference was statistically significant( P=0.012).The content of fasting blood glucose[(5.10±0.43)mmol/L]in GDM group was higher than that in healthy group[(4.33±0.39)mmol/L], the difference was statistically significant( P<0.05), and there was no statistically significant difference in neonatal weight between the two groups( P>0.05). Conclusions:The expression levels of p57Kip2 protein and mRNA in the placental tissues of patients with GDM were higher than those of healthy pregnant women, which suggests that p57Kip2 gene may be involved in the pathogenesis of GDM.