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Four stages of labor:
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First stage: the
longest stage occurs between onset of true labor and the point of cervical
dilation and effecement. Second stage is the expulsion of the
fetus; third stage delivery
of placenta; and fourth stage 1st 4 hrs /p delivery of
placenta
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First stage: divided into 3
phases
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Latent begins with onset of regular contractions, with contractions
q 15 -20 min, lasting 20 -30 secs,
gradually lnc to q 5 7 min, 30 40
secs duration. Little or no cervical dilation. Women stay home. Phase ends
when cervix is 3 cm. Lasts 8.6 hrs for primi, < 6 for multi.
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Active phase begins 4 cm, ends when dilated to 7cm; contractions 2
3 mins, 40 60 secs; cervix should dilate about 1 to 1.5 cm /hr. Primi avg 4.6 hrs, multi 2.4 hrs
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Transition phase shortest, most intense. Dilation from 8 to 10 cm;
contractions q 1.5 2 mins, lasting 60 90 secs (pain & rest about
same). Lasts avg 3.6 hrs for Primi; varies with multi. Woman becomes
restless, angry, wants to go home, wants a C-sec, N&V, etc. Withdraws
from support (spouse, coach, etc), leaving partner feeling useless. NURSE IS
VITAL at this point to both. NURSE must prepare for 2nd stage.
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Second stage: cervix is
completely dilated & effaced; known as pushing stage; up to 3 hrs
for primi, < 30 mins in multi. The
woman bears down, abdominal muscles contract, & help fetal head descend.
When fetal head is visible at vulvar opening, crowning has occurred
and birth is imminent. Some women feel relief, birth is near; others feel
frightened and overwhelmed. Pt can assume different positions. In US,
lithotomy position most common.
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Positional changes of fetus:
called cardinal movements:
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1.Descent: progression of head into pelvis d/t
pressure of amniotic fluid, the contracting uterus, the effects of contractions on mothers
abdominal muscles and diaphragm, and the extension and straightening of the
fetus. Head enters at an oblique or transverse position
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2.Flexion resistance from soft pelvic tissues →
flexion of chin against chest ::
smallest fetal diameter
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3.Internal rotation fetal head must rotate to
accommodate the pelvis; head rotates from left to right
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4.Extension fetal head pivots under symphysis pubis.
Head emerges through extension, followed by occiput, then the face, and
finally the chin
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5.Restitution internal rotation causes shoulders to
enter pelvis in an oblique position and neck becomes twisted. When head is
delivered, the neck untwists and aligns with long axis of fetus.
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6.External rotation shoulders rotate, turning head
further to one side
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7.Expulsion anterior shoulder slips under symphysis
pubis, followed by posterior shoulder. Once shoulders are delivered, the
trunk follows. (Sometimes rather quickly!)
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Figure 15-13 (illustration),
p 325
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Birth sequence Figure 15
-12, p 324
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