A descriptive cross section study on 1350 birth cases at Cantho General Hospital shows that PMR is 10.22 percent, to rupture on admission is 178.33 + or - 184.25 minutes, of which 76.81 percent in the hospital after 60 minutes, to cervical dilatation 3cm 407.59 + or - 258.28 minutes. PMR's time to open a full cervical dilatation is 579.48 + or - 278.01 minutes. Average delivery time to rupture was 685.54 + or - 318.13 minutes. Women 20-25 years of age accounted for 31.16 percent rupture of membrane no differences in age and status of amniotic fluid. There is an association between fluid status with women living in rural areas, fanners, workers, BMI 20
a history of pretenn birth, miscarriage, abortion, leucocytes count. During labor, potential phase is longer in PMR group
active phase is longer than in the intact membrane.