Elevated MMP-2 and MMP-9 amniotic fluid concentrations have been found to be associated with PPROM [30, 31], and amniotic fluid levels of the endogenous inhibitors of matrix metalloproteinases (TIMPs) are also abnormal in PPROM, with increased TIMP-1 levels and decreased TIMP-2 levels compared with rupture of membranes at term [31]. Here, MMP9 is linked to preterm premature rupture of the membranes.