Matrix metalloproteinase-8 in cervical fluid in early and mid pregnancy: relation to spontaneous preterm delivery

To evaluate whether matrix metalloproteinase-8 (MMP-8) concentrations in cervical fluid in early and mid pregnancy are associated with subsequent preterm delivery (PTD) preceded by premature preterm rupture of membranes (PPROMs) or preterm labour (PTL) with intact membranes.

Cervical swab samples were collected from 5180 women in early and mid pregnancy. MMP-8 was determined by immunofluorometric assay (IFMA). The outcome measure was spontaneous PTD at < 37 weeks' gestation.

The overall distribution and the median cervical fluid MMP-8 concentrations in early and mid pregnancy did not differ in women with term delivery and those with subsequent PTD. However, cervical fluid MMP-8 levels were lower in mid pregnancy in women with PTD preceded by PPROM at < 37 weeks as compared with women who delivered at term and women who had PTD initiated by spontaneous onset of labour (p = 0.016 and p = 0.023, respectively).

Our data suggest that molecular mechanisms underlying PTL and PPROM differ and MMP-8 in cervical fluid may reflect different functions of this protease. Due to remarkable overlapping of cervical fluid MMP-8 values, this molecule may not have clinical applicability as a biomarker in cervical fluid at least among asymptomatic women in early and mid pregnancy.