The molecular mechanisms of chorioamniotics membranes rupture during labor are relationated with a group of enzymes named metalloproteinases of extracellular matrix (MMP), the production of these enzymes are elevated in premature rupture of membranes. The collagenase IV (molecular weight 92 kDa) is induced in specific form during both events. We unknown the regulatory mechanisms to these enzymes in the chorioamnios.To determine the presence of apoptosis and expression of (MMP-) in human chorioamnios during the labor and premature of the fetal membranes.The gel lysis using zimography was determined in membranes of 1) Labor, 2) Cesarean section, 3) PRM. The analysis of DNA fragmentation in situ and DNA of the membranes was studied. Using immunohistochemistry techniques was identified MMP-9.It was observed increase of gel lysis in stracts with PRM and labor in comparation with cesarean section. In all the specimens were found apoptotics cells, however, they were scareces, abundance or very abundance in cesarean section specimens, labor or PRM respectively. The fragmentation in situ was confirmed in specimens of DNA. The immunohistochemistry showed positively to MMP-9 in labor and PRM specimens, and not in cesarean section specimens. The MMP-9 immunorreactivity was extensive in PRM and only was found apoptosis.The results demonstrate that apoptosis and expression-activity of MMP-9 can be associated to membranes rupture during labor and lysis, the same explanation may be true for the increased expression of MMP-9 in PRM both phenomena seems to have a sequence.