Page 215 - ترم ثاني كتاب تمريض صحة الام الكتروني

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❖ Mechanism of the third stage of labor:

Schultz Mechanism:

Commonest, occurs in 80% of cases. The central part of the placenta separates

first as the placenta is firmly attached at its edges. A retroplacental hematoma forms

and the placenta is delivered by its fetal surface followed by the membranes

containing the blood clot. This mechanism is lees liable to be followed by bleeding

or retained fragments. Actually, the placenta is delivered like inverted umbrella.

Duncan Mechanism:

In 20% of cases. The placenta separates at its lower edge, and is delivered

sideways with the maternal and fetal surfaces appearing together. There is no retro

placental hematoma. It is more liable to be followed by bleeding and retained

fragments.

Placenta Expulsion:

After separation of the placenta from the uterine wall, continued uterine contractions

cause the placenta to be expelled and the placenta is delivered either by the natural

bearing down effort of the mother or by gentle pressure on the contracted fundus by

a physician or nurse.

➢ N.B :

- Contraction means temporary shortening of the muscle fibre.

- Retraction means permanent shortening of the muscle fibre.

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