C-peptide levels and the risk of diabetes and pre-diabetes among Chinese women with gestational diabetes.

•The association of C-peptide and the risks of postpartum diabetes and pre-diabetes among women with prior GDM was examined.•The analysis showed a positive association between plasma C-peptide levels and the risks of diabetes and pre-diabetes among Chinese women with prior GDM.•It suggested that elevated C-peptide levels may be a predictor of postpartum diabetes and pre-diabetes among GDM women.