First trimester serum matrix metalloproteinase-7 is a poor predictor of late-onset preeclampsia

Objectives: This study aims to evaluate matrix metalloproteinase-7 as a first trimester biomarker for late-onset preeclampsia, both alone and in combination with mean arterial pressure, uterine artery pulsatility index, and maternal characteristics. Study design: We conducted a nested case-control study from a prospective cohort consisting of 416 pregnant women who attended a routine first trimester scan. Baseline variables were obtained at inclusion and analysed subsequently to formation of case and control groups. The study was designed to detect a mean difference of > 15% in matrix metalloproteinase-7 concentrations between groups with a statistical power of 80%. Main outcome measures: The primary outcome was preeclampsia with delivery after 34 weeks of pregnancy. Results: The median matrix metalloproteinase-7 concentration in cases of late-onset preeclampsia (n = 27) was marginally lower compared to normotensive controls but this difference was not statistically significant. Matrix metalloproteinase-7 predicted 14.8% of cases at a 10% false-positive rate. Addition of matrix metalloproteinase-7 to any combination of variables did not significantly improve their performance. Conclusions: Matrix metalloproteinase-7 is not a useful biomarker for late-onset preeclampsia, neither alone nor in combination with mean arterial pressure, uterine artery pulsatility index, or maternal characteristics.