Amniotic fluid concentrations of collagenase-1 and collagenase-3 are increased in polyhydramnios

OBJECTIVE: Polyhydramnios places increased tension on the fetal membranes and should conceptually be associated with an increased need for tissue remodeling to prevent premature rupture of membranes (PROM). Herein we use polyhydramnios as a model to study the association of the collagenase class of matrix metalloproteinases (MMPs) with tissue remodeling during pregnancy. METHODS: Amniotic fluids were collected by transabdominal amniocentesis from women with polyhydramnios and from women with normal amniotic fluid volume at second trimester, third trimester and at term. Fluids were assayed for MMP-1 and MMP-13 (collagenase-1 and 3) using ELISA. The concentrations in polyhydramnios were compared with subjects undergoing amniocentesis with normal amniotic fluid volume. Statistical comparisons were made using Scheffe's method for correction in multiple means comparison. P of <0.05 was considered statistically significant. RESULTS: MMP-1 and MMP-13 are present in the amniotic fluid at all stages of pregnancy. The concentrations of these MMPs were significantly elevated in the polyhydramnios samples independent of gestational age. CONCLUSION: Polyhydramnios is associated with increased amniotic fluid concentrations of MMP-1 and MMP-13 suggesting their role in tissue remodeling.