The decrease in MMP-2 and MMP-9 activity or ratios of MMP-2/TIMP-2 and MMP-9/TIMP-1 might be involved in the pathogeneses of early pregnancy loss and preeclampsia (Graham and McCrae, 1996; Choi et al., 2003; Shokry et al., 2009; Plaks et al., 2013; Gutierrez et al., 2020; Lin et al., 2020). The gene discussed is MMP9; the disease is preeclampsia.