Page 170 - كتاب تمريض نسا الاكتروني
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                      which is produced in increased amounts by the fetal suprarenal near term with
                      fetal maturity.
                 -  Anencephaly is a congenital anomaly in which the fetal vault of the skull is

                     absent, the brain and pituitary are atrophied. (Incompatible with life).

                 -   In These cases, the fetal suprarenal are not stimulated by ACTH and onset of

                     labor may therefore, be delayed.







            6 – Uterine distension:


                 Near term, fetal growth continues and uterine growth becomes slower; the result is


                increased  distension  of  uterine muscles initiating  uterine contractions.  Preterm
                labour may occur with early distension, e.g.: twins and polyhydramnios.


            7 – Placental ischaemia:


                  -  Resulting  in lower  production  of  oxytocin’s-  an enzyme  thought  to be


                     responsible for oxytocin degradation-with subsequent rise in oxytocin level.
            8 – Stretch of the lower-uterine segment:



                 By the presenting part near term may contribute to the onset of labor.


              Premonitory Symptoms and Signs of Labor:
            There are symptoms and signs, which may occur in the last week or days of pregnancy
            before the actual onset of labor and include:


            1-Shelving:
            The fundus of the uterus descends slightly &falls forwards; it brings the fetus in the
            direction of the axis of the pelvis.






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