Download DEFINITION OF LABOR

DEFINITION OF LABOR
‘LABOR can be defined as spontaneous painful uterine
contractions associated with the effacement and dilatation of
the cervix and the descent of the presenting part’
Intensity of Pain in Labor
(Melzack and Katz, 1999).
 Early 1st stage: before fetal head reaches zero
station, pain impulses arise primarily from uterus
 via visceral afferents enter spinal cord at T10-L1.
 Late 1st stage & 2nd stage: pain impulses arise from
uterus, pelvic structures, vagina, & perineum.
 3rd stage of labor is usually well tolerated with
spontaneous placental delivery.
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Pain of Childbirth

Visceral pain
 First stage
 T10 - L1

Somatic pain:
 Second stage
 S2-S4
Pain Management Options
 Non-pharmacological
 Systemic analgesia
 Epidural analgesia
 Combined Spinal Epidural Analgesia
(CSE)
Pain Management Options
Non-pharmacological:
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Emotional Support
Touch & Massage
Heat & Cold
Hydrotherapy
Vertical Position
TENS
Acupuncture
Hypnosis
Con’t Analgesia
Systemic medications
Narcotics:
Although narcotics provide both analgesic &
sedation, their S.E are:
II.
A.

1.
2.
3.
Maternal: Orthostatic hypotension, nausea,
vomiting.
Fetal: ↓ beat-to-beat variability of FHR.
Neonatal: respiratory depression  Rx: Naloxone
(Narcan).
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Con’t Analgesia
Meperidine (Demerol or Pethidine):
 Best use in early stages of labor, less effective once
labor is well established.
 If IV (25-50 mg)  peak effect = 7-8 min. Duration =
1.3-3 hrs.
 If IM (50-100 mg)
 peak effect = 2-4 hrs.
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Disadvantages of Pethidine.
Somnolence
 Confusion and even hallucinations.
 Nausea and / or vomiting.
 Dizziness is common.

 Desaturation episodes (SpO2 between 70 to 90%) in about
50% of women (Reed et al 1989, Minnich et al 1990).
 Elimination of Pethidine from the bodies of both mother and
child is relatively slow,
Sedative-Tranquillizers

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These agents given in combination with a
narcotic.
The phenothiazine –Promethazine (Phenergan)25 mg IM or 12.5 mg IV.
Relieves anxiety, controls nausea & vomiting, ↓
narcotic requirements during labor.
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Con’t Analgesia
III. Inhalational analgesia (Entonox)
 Provides partial pain relief during labor as well as @



delivery.
50% Nitrous oxide in O2. It’s administered with a mask /
mouthpiece in a manner such that the parturient remains
awake, cooperative & in control of her airway  to
prevent pulmonary aspiration of gastric contents.
Does not prolong labor or interfere with uterine
contractions but administration > 20 minutes may result
in neonatal depression.
< risk of neonatal depression when compared with
narcotics.
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Anesthesia
(Regional anesthesia)
Peripheral nerve block:
A.


Local infiltration for episiotomy (Lidocaine).
Pudendal block.
Central nerve block:
B.


Epidural anesthesia.
Spinal (subarachnoid) block.
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Pudendal block
:

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Administered shortly before delivery to anesthetize
pudendal nerve.
Insert needle  aspirate with syringe to check for
absence of blood  inject 1% Lidocaine on each side.
Analgesia produced in lower birth canal & perineum
provides maternal comfort for low forceps delivery &
episiotomy.
Advantages: easy to administer, not a/w maternal
hypotension/ fetal distress.
Disadvantage: incomplete analgesia @ time of delivery,
since pain of uterine contraction is unaffected.
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Epidural anesthesia
 In USA
approximately 60
percent of women
choose epidural or
combined spinalepidural analgesia for
pain relief during
labor.
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Advantages of Epidural Analgesia
 Provides superior pain relief
 90% to 95% are satisfied with epidural analgesia.
 Facilitates patient cooperation during labor and delivery
 Decreases maternal hyperventilation
 Avoids opioid-induced maternal and neonatal respiratory
depression
Advantages of Epidural Analgesia
 Extend the duration of block to match the duration of labor
 Allows extension of anesthesia for cesarean delivery
Epidural Analgesia Contraindications:
Co-operation
 Active neurologic disorder
 Coagulopathy
 Hypotension
 Systemic / local infection
Epidural Complications
Early
Late
 IV toxicity
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 LA toxicity
 Hypotension
 High block/total spinal
 Extensive motor block
 Urinary retention
 Labour progress
PDPH
Neurological injury
Epidural abscess
Epidural hematoma
Back pain
Controversy Still Remains Over the
Effects of Epidural Analgesia
 rate of c-section delivery
 rate of instrument-assisted delivery (vacuum
extraction and forceps)
 prolongation of labor
 effects on the fetus
Segal (2000)
 Meta-analysis of 37,000 patients in a variety of different
practice settings and time periods in several different
countries showed:
 No significant change in
 overall c-section delivery rate
 rate of c-section deliveries for dystocia
 rate of forceps delivery
Prospective, Randomized Trials
 11 clinical trials since 1990 have assessed the effect of epidural
analgesia on c-section rates by randomizing women to
opiod versus epidural analgesia
 Epidural analgesia associated with an increase in c-section
delivery rate in only one study
Sharma (2004)
 Individual meta-analysis of 2700 nulliparous women
 No difference in overall c-section rate (10.5% vs. 10.3%)
or rate for dystocia
 Significant increase in forceps deliveries (13% vs. 7%) in
epidural group
 Epidural analgesia was associated with prolongation of
1st and 2nd stages of labor, increased need for oxytocin,
and maternal fever
 One and 5 minute apgar scores significantly worse in the
intravenous meperidine group
 Significantly lower pain scores and greater satisfaction
both stages of labor in epidural group
Characteristics of Patients Who
Select Epidural Analgesia
 earlier stage of labor at admission
 higher fetal station at admission
 greater use of oxytocin
 smaller pelvic outlets and larger babies
 more fetal malpresentation
 more likely to be primagravid
Pain In Labor Itself
 Pain early in labor is associated with a slower labor
resulting in an increased rate of c-section and
instrumental deliveries
 More pain in labor is associated with a higher
likelihood of selecting epidural analgesia
Spinal (subarachnoid) block

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Injection of local anesthetic (Tatracaine,
Bupivacaine, or Lidocaine) into subarachnoid
space thru a spinal needle placed in L3-4
interspace.
Fastest onset.
Least drug exposure for fetus because small dose
required.
Be aware of rapid hypotension & preload mother
with 1000 mL IV fluid.
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