Cervicovaginal matrix metalloproteinase-9 and cervical ripening in human term parturition

Objective: To investigate the changes of matrix metalloproteinase-9 (MMP-9) in cervicovaginal fluid during pregnancy and its association with parturition. Study design: A prospective study was conducted on nulliparous women between 16 and 42 weeks with normal singleton pregnancies in the following categories: (1) preterm control (n = 39); (2) term labor induction without labor or rupture of membranes (n = 68); (3) term spontaneous labor with intact membranes (n = 42); (4) term premature rupture of membranes (n = 24). The MMP-9 concentration in the cervicovaginal fluid was measured by immunoassay. Results: (1) Cervicovaginal MMP-9 did not change significantly with advancing gestation until 37 weeks, and significantly increased after 37 weeks. (2) Cervicovaginal MMP-9 levels were similar in women with no labor, spontaneous labor, and premature rupture of membranes at term. (3) For the induced labor group, a high Bishop score (≥4) was significantly correlated with cervicovaginal MMP-9. However, an elevated cervicovaginal MMP-9 did not predict achieving active phase of labor or vaginal delivery after labor induction. Conclusion: Cervicovaginal MMP-9 correlated with cervical ripening before labor at term. However, cervicovaginal MMP-9 did not change with spontaneous labor or rupture of membranes at term and did not predict success of labor induction.