When evaluating phthalates metabolites separately and combined in the first and second trimesters of pregnancy, the same research group found that phthalates and their mixtures may be involved in maternal glucose metabolism, since in the first trimester there was a negative correlation between MBP, MCNP, and MCPP levels and GDM and impaired glucose tolerance, while a positive association was found for MiBP and MHBP levels and impaired glucose tolerance and GDM, respectively. This evidence concerns the gene MBP and gestational diabetes.