MMP8 and gestational diabetes: MMP-8 and -9 levels in gingival mucosa have been found to be elevated during early pregnancy in women with severe periodontitis, which may be related to the onset of gestational diabetes: in a previous study, it was reported that 14% of pregnancies were diagnosed with GDM, and women with periodontitis stages III and IV had higher concentrations of MMP-8 and -9 in their gingival crevicular fluid (GCF) [52].