Page 175 - كتاب تمريض نسا الاكتروني

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• Second stage (expulsive stage): begins with complete dilatation of the cervix
and ends with delivery of the fetus.

• 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.

.

Phases of cervical dilatation:

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