Page 194 - ترم ثاني كتاب تمريض صحة الام الكتروني
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                 •  Third stage (placental stage): begins with delivery of the fetus and ends with

                 delivery of the placenta.

                 •  Fourth stage: is the first 2 hours following delivery.


                  Duration of Labor   First Stage                  Second Stage   Third Stage
                  Primigravida                    12     –    16          1-2                10-20

                                                  hours                   hours              minutes
                  Multipara                       6-8 hours               10-30              10-20

                                                                          minutes            minutes


                ▪  First Stage of Labor:

                      Definition
                 begins with the onset of true labor pains and ends with fully dilatation of the cervix.
                 It takes about 12 hours in the primigravida and 6 hours in the multigravida.


            ➢  Factors  causing dilatation :

                •  Uterine contractions and retractions.

                •  Dilating effect of the bag of forewaters (before rupture of membranes).


                •  Pressure  of  presenting  part  (vertex)  on  cervix  and  lower  uterine  segment
                    causes reflex augmentation of contractions after rupture of membranes.


                •  Changes in cervix: During the last days of pregnancy, make it readily dilatable

                    eg: increased vascularity, edema, changes in ground substances and collagen

                    fibers.









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