Spontaneous abortion is preceded by an altered serum concentration of matrix metalloproteinases.

Objective: To evaluate the usefulness of the serum concentration of nine matrix metalloproteinases (MMPs) as biomarkers of spontaneous abortion. Methods: A retrospective nested cohort case-control study was carried out in Zacatecas, Mexico. MMP-1-3, MMP-7-10, and MMP-12-13 were analyzed in serum from women who had spontaneous abortion of unknown causes (n = 7), who suffered abortions attributed to urinary tract infection (n = 7) and from those with healthy pregnancies without complications (controls; n = 20). Protein profiles were determined between 11 and 13 weeks of gestation (GW) using the Bio-Plex Pro Human MMP Panel. Differences in serum MMP concentrations between the study groups and their correlation with clinical findings were evaluated statistically. Results: There were differences in serum concentrations of MMP-9 between groups of spontaneous abortion of unknown cause (13.2 +/- 7.5 ng/mu L), abortion attributed to urinary tract infection (11.6 +/- 5.8 ng/mu L) and the controls (11.8 +/- 16.5 ng/mu L) (p = .022). Compared with controls, higher serum concentrations of MMP-8, MMP-9, and MMP-10 were observed in the group of spontaneous abortions of unknown causes (p value < .05). A negative correlation between MMP-8 and MMP-9 and urine density was also identified (r = -0.949, p value = .0167; and r = -0.947, p = .0167). Conclusions: Elevated serum concentrations of MMP-8, MMP-9, and MMP-10 were associated and preceded by the appearance of spontaneous interruption of pregnancy of unknown causes. Our results support the hypothesis that altered MMP modulation may be related with the pathogenesis of spontaneous abortion.