Objective To assess the effect of insulin combined with metformin on blood glucose level of patients with gestational diabetes mellitus（GDM）and neonatal neurodevelopment.Methods A total of 104 patients with GDM who were treated at a Henan hospital between June 2016 and June 2017 were included in this study.Based on a random number table

patients were divided into the trial group and the control group

52 in each group.Patients in the control group received insulin alone

while those in the trial group received insulin plus metformin.The postpartum fasting blood glucose

2 hpostprandial blood glucose level

proportion of patients achieving the target glucose level

as well as neonatal neurodevelopment were compared between the two groups.Results The postpartum fasting blood glucose and 2 hpostprandial blood glucose level were significantly lower in the trial group than those in the control group（P<0.05）

and the proportion of patients achieving the target glucose level was also significantly higher in the trial group（P<0.05）.The neonatal behavioral neurological assessment（NBNA）overall score as well as the passive muscle tension

active muscle tone

behavior ability

primitive reflection

and general assessment sub-scores were significantly higher in the trial group than those in the control group（P<0.05）.Besides

the incidence of neonatal neurodevelopment abnormalities was significantly lower in the trial group compared with that in the control group（P<0.05）.Conclusion For patients with GDM

insulin combined with metformin is effective in controlling the blood glucose level and minimizing the incidence of neonatal neurodevelopment abnormalities

which deserves widespread clinical application.