Transcript Document 7230132

Labor
 Labor is the physiologic process by
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which a fetus is expelled form the
uterus to the outside world.
It involves the sequential
integrated changes in the uterine
decidua, and myometrium.
Changes in the uterine cervix tend
to precede uterine contractions
Dilatation: the enlarging of the
cervix to 10 centimeters.
Effacement: the thinning of the
cervix. Your cervix starts out being
two inches long, and 50% effaced
would be a 1 inch cervix.
Labor - Mechanics
 Uterine contractions have two major goals:
To dilate cervix
2. To push the fetus through the birth canal
 Success will depend on the three P’s:
1. Powers
2. Passenger
3. Passage
1.
Power
Uterine contractions
 Power refers to the force
generated by the contraction of
the uterine myometrium
 Activity can be assessed by the
simple observation by the mother,
palpation of the fundus, or
external tocodynamometry.
 Contraction force can also be
measured by direct measurement
of intrauterine pressure using
internal manometry or pressure
transducers.
Power
 There is no specific
criteria for adequate
uterine activity
 Generally 3-5
contractions in a 10
minute period is
considered adequate
labor
Passenger
Passenger =fetus
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Fetal variables that can affect labor:
Fetal size
Fetal Lie – longitudinal, transverse or oblique
Fetal presentation – vertex, breech, shoulder, compound
(vertex and hand), and funic (umbilical cord).
Attitude – degree of flexion or extension of the fetal head
Position
Number of fetuses
Presence of fetal anomalies – hydrocephalus,
sacrococcygeal teratoma
Cervical effacement and dilation
Station
 Station – degree of
descent of the presenting
part of the fetus,
measured in centimeters
from the ischial spines in
negative and positive
numbers.
 -5 is a floating baby,
 0 station is said to be
engaged in the pelvis,
 and +5 is crowning.
Passage
Passage = Pelvis
 Consists of the bony pelvis and
soft tissues of the birth canal
(cervix, pelvic floor
musculature)
 Small pelvic outlet can result in
cephalopelvic disproportion
 Bony pelvis can be measured by
pelvimetry but it not accurate
and thus has been replaced by a
clinical trial of labor
Passage
 www.uptodate.com
The Stages of Labor
First Stage
 Interval between the onset
of labor and full cervical
dilation
 Two phases:
 Latent phase – onset o f
labor with slow cervical
dilation to ~4 cm and
variable duration
 Active phase – faster rate of
cervical change, 1-1.2 cm
/hour, regular uterine
contractions
The Labor Curve
 First stage - A: latent phase; B + C + D: active phase; B: acceleration;
C: maximum slope of dilation; D: deceleration; E: second stage.
Labor
 Freidman’s curve is
a good guideline for
expected
progression in
labor and therefore
helpful to note
abnormal labor
patterns.
Labor
NulliG
MultiG
1st Stage
Active
phase
Duration
6-18 h
2-10 h
Dilation
~1 cm/h
~1.5 cm/h
Arrested
>2 h
>2h
2nd Stage
0.5-3 h
5-30 min
3rd Stage
0-30 min
0-30 min
Fig 1: An idealized labor pattern. The normal patterns of cervical dilation
(solid line) and descent (broken line) as they are traced against elapsed time in
labor. The distinctive phases of the first stage are shown. The active phase
comprises the interval from the onset of the acceleration phase to the
beginning of the second stage.
Labor – Second Stage
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Interval between full
cervical dilation to
delivery of the infant.
 Characterized by descent
of the presenting part
through the maternal
pelvis and expulsion of the
fetus.
 Indications of second
stage:
1. Increased maternal show
2. Pelvic/rectal pressure
3. Mother has active role of
pushing to aid in fetal
descent.
Labor – Second Stage
 Molding is the alteration of the
fetal cranial bones to each other
as a result of compressive forces
of the maternal bony pelvis.
 Examining the fetal head
during the second stage may
become difficult due to
molding
 Caput is the localized
edematous area on the fetal
scalp caused by pressure on the
scalp by the cervix.
 PrimiG – 0.5-3 h; mulitG 030min
 Suctioning the
nasopharynx
 Clamp the umbilical cord
 Cut between the clamps
Labor – Third Stage
Placental separation and delivery.
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The time from fetal
delivery to delivery of
the placenta
Signs of placental
separation:
a. The uterus becomes
globular in shape
and firmer.
b. The uterus rises in
the abdomen.
c. The umbilical cord
descends three (3)
inches or more
further out of the
vagina.
d. Sudden gush of
blood.
Labor – Third Stage
 Placenta is delivered using one
hand on umbilical cord with
gentle downward traction. Other
hand on abdomen supporting
the uterine fundus.
 Risk factor for aggressive traction
is uterine inversion.
 Obstetrical emergency!!
 Normal duration between 0-30
min for both PrimiG and MultiG
 Inspect the placenta for completeness
 AMTSL = Active management of third stage of labour. RP = retained placenta.
CCT = controlled cord traction. Hb = Haemoglobin. BP = Blood pressure. MRP
= Manual removal of placenta. Hb = haemoglobine.
Labor – Fourth Stage
 Refers to the time from delivery of the placenta to
1 hour immediately postpartum
 Blood pressure, uterine blood loss and pulse rate
must be monitor closely ~ 15 minutes
 High risk for postpartum hemorrhage from:
 Uterine atony, retained placental fragments,
unrepaired lacerations of vagina, cervix or
perineum.
 Occult bleeding may occur – vaginal hematoma
 Be suspicious with increased heart rate,
pelvic pain or decreased BP!!!!!!
Cardinal Movements of Labor
This refers to the movements
made by the fetus during the
first and second stage of
labor. As the force of the
uterine contractions
stimulates effacement and
dilatation of the cervix, the
fetus moves toward the
cervix.
When the presenting part
reaches the pelvic bones, it
must make adjustments to
pass through the pelvis and
down the birth canal
Seven distinct
movements:
1. Engagement
2. Descent
3. Flexion
4.Internal rotation
5. Extension
6.External
rotation/restitut
ion
7. Expulsion
Cardinal Movements of Labor
Engagement
 Passage of the widest diameter fetal presenting part below
the plane of the pelvic inlet
 The head is said to be engaged if the leading edge is at the
level of the ishial spines.
Descent
 Refers to the downward passage of the presenting part
through the bony pelvis
 Not steady process
 Greatest at deceleration phase of first stage and during 2nd
stage of labor
Cardinal Movements of Labor
Flexion
 Occurs passively as the head descends due to the shape
of the bony pelvis.
 Partial flexion occurs naturally but complete flexion
usually occurs only in the labor process
 Complete flexion places the fetal head in optimal
smallest diameter to fit through the pelvis
Internal Rotation
 Rotation of the fetal head from occiput transverse to
occiput either in anterior or posterior position
 Occurs passively due to the shape of the bony pelvis
Cardinal Movements of Labor
Extension
 Occurs when the fetus has descended to the level of the
vaginal introitus
 When occiput is just past the level of the symphysis, the
angle of the birth canal changes to upward position
External Rotation/Restitution
 As the head is delivered, it rotates back to its original
position prior to internal rotation
 It aligns anatomically with the fetal torso
 The release of the passive forces on the fetal head allows it to
return to appropriate position
Expulsion
 Delivery of the fetus
 After delivery of the fetal head,
descent and intraabdominal
pressure by mother brings
shoulder to the level of the
symphysis
 Downward traction allows
release of the shoulder and the
fetus is delivered.
Analgesia in labor
Discomfort during Labor and Birth
Pain and discomfort experienced during labor have
two neurologic origins: visceral and somatic
Neurologic origins
 Visceral pain: from cervical changes, distention of lower uterine segment,
and uterine ischemia
 Located over the lower portion of abdomen
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Referred pain: originates in uterus, radiates to abdominal wall, lumbosacral
area of back, iliac crests, gluteal area, and down the thighs
Somatic pain: pain described as intense, sharp, burning, and well localized
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Stretching and distention of perineal tissues and pelvic floor to allow passage
of fetus, from distention and traction on peritoneum and uterocervical
supports during contractions, and from lacerations of soft tissue
Perception of pain
 Threshold remarkably similar in all,
regardless of gender, social, ethnic, or
cultural differences
 Differences play definite role in person’s
perception of and behavioral responses to
pain
Expression of pain
 Pain results in physiologic effects
and sensory and emotional
(affective) responses
 Emotional expressions of
suffering often seen
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Increasing anxiety
Writhing, crying, groaning,
gesturing (hand clenching and
wringing), and excessive muscular
excitability
Cultural expression of pain varies
Factors influencing pain response
 Physiologic factors
 Culture
 Anxiety
 Previous experience
 Childbirth
preparation
 Comfort and support
 Environment
Distribution of labor pain
 A. Distribution of labor pain during first stage
 B. Distribution of labor pain during later
phase of first stage and early phase of
second stage
 C. Distribution of labor pain during later
phase of second stage and during birth
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(Gray shading indicates areas of mild
discomfort; light-colored shading indicates
areas of moderate discomfort; dark-colored
shading indicates areas of intense discomfort.)
Nonpharmacologic Management
of Discomfort
 Nonpharmacologic measures often simple, safe, and
inexpensive
 Provide sense of control over childbirth and measures
best for woman
 Methods require practice for best results
 Try variety of methods and seek alternatives, including
pharmacologic methods, if measure used is not
effective
Nonpharmacologic Management
of Discomfort
 Childbirth education
 Dick-Read method
 Lamaze method
 Bradley method
 Relaxing and breathing techniques
 Relaxation
 Imagery and visualization
 Music
 Touch and massage
 Breathing techniques
 Effleurage and counterpressure
 Water therapy (hydrotherapy)
 Transcutaneous electrical nerve stimulation
Pharmacologic Management
of Discomfort
 Sedatives
 Analgesia and anesthesia
 Anesthesia
 Systemic analgesia
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Opioid agonist analgesics
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Opioid (narcotic) agonist–
antagonist analgesics
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Co-drugs
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Ataractics
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Opioid (narcotic) antagonists
 Nerve block analgesia and
anesthesia
 Local perineal infiltration
anesthesia
 Prudendal nerve block
 Spinal anesthesia (block)
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Disadvantages
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Medication reactions (allergy)
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Hypotension
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Ineffective breathing
Headache
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Autologous epidural blood patch
Pain Pathways and Sites of
Pharmacologic Nerve Blocks
A. Pudendal block; suitable
during second and third stages
of labor and for repair of
episiotomy
B.
Epidural block; suitable
during all stages of labor and for
repair of episiotomy
Pain Pathways and Sites of
Pharmacologic Nerve Blocks
Nerve block analgesia and
anesthesia
Epidural anesthesia/analgesia
 Lumbar epidural
anesthesia/analgesia
 Walking epidural analgesia
 Epidural and intrathecal opioids
Membranes and spaces of spinal
cord and levels of sacral,
lumbar, and thoracic nerves
Cross section of vertebra and
spinal cord
Levels of Anesthesia Necessary for Cesarean
and Vaginal Births
Cesarean birth
Vaginal birth
Care Management
 Plan of care and interventions (cont’d)
 Administration of medication
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Intravenous route
Intramuscular route
Spinal nerve block
 Signs of potential problems
 Safety and general care
 Anesthesia in the obese woman
Key Points
 Expected outcome of preparation for childbirth and
parenting is “education for choice”
 Nonpharmacologic pain and stress management
strategies are valuable for managing labor discomfort
alone or in combination with pharmacologic methods
 Gate-control theory of pain and stress response are
bases for many of the nonpharmacologic methods of
pain relief
 Type of analgesic or anesthetic used is determined in
part by stage of labor and method of birth
 Opioid effects can be potentiated with ataractics
In Summary
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Know the different stages of labor
Know the labor curve
Know the cardinal movements of labor
Know the causes of postpartum hemorrhage
 MD must understand medications, expected effects, potential adverse reactions, and
methods of administration
 Maternal fluid balance is essential during spinal and epidural nerve blocks
 Maternal analgesia or anesthesia potentially affects neonatal neurobehavioral response
 Use of opioid agonist-antagonist analgesics in women with preexisting opioid
dependence may cause symptoms of abstinence syndrome (opioid withdrawal)
 General anesthesia rarely used for vaginal birth
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May be used for cesarean birth or when needed in emergency childbirth situation
Thank you for your attention!