Of note, at the year 2000, we first measured MMP-8 in AF obtained and stored in polyprophylene tubes at 70°C from most patients enrolled into our biobank between January 1993 and December 1999 for our previous two studies (29, 38), and verified that there was no significant difference in the median concentration of AF MMP-8 among the sampling year in the same context of situation (i.e., asymptomatic mid-trimester pregnant women). Here, MMP8 is linked to atrial fibrillation.