ABNORMAL LABOR

PRESENTED BY
DR.SEENAA ALSAADY
 Objectives
• Forth stage students can understand from this
lecture the following:
• definition of abnormal labour, its etiology
• detection of abnormal labour and its
management
 Abnormal labour

• An Abnormal Labour is also called Dystocia

• Dystocia is a Greek word
• dys (difficult)
• tokos (birth)
• meaning an abnormal or difficult birth
 Etiology
a. Uterine dystocia
b. Fetal dystocia
c. Pelvic dystocia
 a) Uterine dystocia
• A difficult labour that occurs due to weak or
excessive uterine action
• High risk for abnormal labour include
– Overweight cause fetal macrosomia
– Short stature may have small pelvis
– Infertility (failure to ovulate)
– Masculine characteristics
– Congenitally abnormal uterus, an over distended
uterus as in case in multiple pregnancy, or
polyhyramnios
– Lack of reflex stimulation of the myometrium related
to malpresentations such as posterior positions, face,
brow, or breech presentations; or transverse lie
• Fetopelvic disproportions, uterine activity usually
slows if the pelvis is too small for fetal descent
• Over stimulation of the uterus with oxytocin
• Extreme maternal exhaustion causing the adrenal
medulla to secrete catecholamines that interfere
with uterine contractility
• Dehydration, electrolyte imbalance
• Administration of anlagesic too early in labour
• Use of continuous epidural analgesia
 b) Fetal dystocia
A difficult labour which occurs due to the size, shape
and presentation of the fetus causes fetal dystocia.
This condition is usually related to one of the
following:
Abnormal fetal presentation or position, such as
face, brow, or breech, posterior occiput
presentation, or transverse lie
Fetal anomalies such as hydrocephalus, abdominal
enlargement, tumours, or conjoined twins
Abnormal fetal position and lie
 c) Pelvic dystocia
• A difficult labour that occurs due to one of the
following condition:
• Small pelvic inlet, midpelvis, or pelvic outlet as a
result of heredity

• Previous pelvic fracture or disease

Pelvic disease
 Abnormal labour progress
• Labor is said to be abnormal when there is
poor progress (as evidenced by a delay in
cervical dilatation or descent) and /or the
fetus shows signs of compromise.
Prolonged labour:
The labor is said to be prolonged when the combined
duration of the first and second stage is more than the
arbitrary time limit of 18 hours.
The prolongation may be due to protracted cervical
dilatation in the first stage and/or inadequate descent of the
presenting part during the first or second stage of labor.
Labor is considered prolonged when the cervical dilatation
rate is less than 1 cm/h and descent of the presenting part is
less than 1 cm/h for a period of minimum 4 hours.
CAUSES OF PROLONGED LABOR:
Any one or combination of the factors in labor could be
responsible.

First stage: Failure to dilate the cervix is due to:

Fault in power: Abnormal uterine contraction such as uterine

(common) or incoordinate uterine contraction
Fault in the passage: Contracted pelvis, cervical dystocia,
pelvic tumor or even full bladder

Fault in the passenger: Malposition (OP) and

malpresentation (face, brow), congenital anomalies of the
fetus (hydrocephalus).

Others: Injudicious (early) administration of sedatives and

analgesics before the active labor begins.
Second stage: Sluggish or non-descent of the presenting part
in the second stage is due to:

Fault in the power: (1) Uterine inertia, (2) Inability to bear

down, (3) Regional (epidural) analgesia, (4) Constriction ring.

Fault in the passage: (1) Cephalopelvic disproportion, android

pelvis, contracted pelvis, (2) Undue resistance of the pelvic
floor or perineum due to spasm or old scarring, (3) Soft tissue
pelvic tumor.

Fault in the passenger: (1) Malposition (occipitoposterior),

(2) Malpresentation, (3) Big baby (4) Congenital malformation
of the baby.
DIAGNOSIS:

Prolonged labor is not a diagnosis but it is the

manifestation of an abnormality, the cause of which
should be detected by a thorough abdominal and
vaginal examination. Diagnosis is usually done by
partogram
The partogram

The introduction of a graphic record of labour in the form of

a partogram has been an important development. This record
allows an instant visual assessment of the rate of cervical
dilatation and comparison with an expected norm, according to
the parity of the woman, so that slow progress can be
recognized early and appropriate actions taken to correct it
where possible. Other key observations are entered on to the
chart, including the frequency and strength of contractions, the
descent of the head in fifths palpable, the amount and colour of
the amniotic fluid draining, and basic observations of maternal
well-being, such as blood pressure, pulse rate and temperature.
A line can be drawn on the partogram at the end of
the latent phase demonstrating progress of 1 cm
dilatation per hour. Another line (‘the action line’) can
be drawn parallel and 4 hours to the right of it. If the
plot of actual cervical dilatation reaches the action
line, indicating slow progress, then consideration
should be given to a number of different measures
which aim to improve progress. Progress can also be
considered slow if the cervix dilates at less than 1 cm
every 2 hours.
First stage: First stage of labor is considered prolonged
when the duration is more than 12 hours.
The rate of cervical dilatation is <1 cm/h in a primi and <1.5
cm/h in a multi. The rate of descent of the presenting part is
<1 cm/h in a primi and <2 cm/h in a multi.
PROLONGED LATENT PHASE
Latent phase is the preparatory phase of the uterus and the
cervix before the actual onset of labor.
Mean duration of latent phase is about 8 hours in a primi
and 4 hours in a multi.(3-8 hours). A latent phase that
exceeds 20 hours in primigravidae or 14 hours in
multiparae is abnormal.
The causes include: (1) unripe cervix, (2) malposition and
malpresentation, (3) cephalopelvic disproportion, (4)
premature rupture of the membranes, (5) induction of
labor and (6) early onset of regional anesthetic.
Prolonged latent phase may be worrisome to the
patient but does not endanger the mother or fetus.

Management:
Expectant management is usually done unless there is
any indication (for the fetus or the mother) for
expediting the delivery. Rest and analgesic are usually
given. When augmentation is decided, medical methods
(oxytocin or prostaglandins) are preferred. Amniotomy
is usually avoided. Prolonged latent phase is not an
indication for cesarean delivery.
Disorders of the active phase: Active phase disorders may
be divided into: (A) protraction and (B) arrest disorders.
(A) Protracted active phase: When the rate of cervical
dilatation is <1.2 cm/h in a primipara and <1.5 cm/h in a
multipara. A protracted active phase may be due to: (i)
inadequate uterine contractions, (ii) cephalopelvic
disproportion, (iii) malposition (OP) or malpresentation
(brow) or (iv) regional (epidural) anesthesia.
(B) Arrest disorder: Arrest of dilatation is defined when no cervical
dilatation occurs after 2 hours in the active phase of labor. It is
commonly due to inefficient uterine contractions. No descent for a
period of more than 2 hour is called arrest of descent. It is
commonly due to CPD
Second stage:
Mean duration of second stage is 50 minutes for nullipara
and 20 minutes in multipara. Prolonged second stage is
diagnosed if the duration exceeds 2 hours in nullipara and
1 hour in a multipara when no regional anesthesia is used.
One hour or more is permitted in both the groups when
regional anesthesia is used during labor (ACOG).
Disorders of the second stage:
(i) Protraction of descent is defined when the descent of the
presenting part (station) is at less than 1 cm/h in a nullipara or less than
2 cm/h in a multipara.
(ii) Arrest of descent is diagnosed when no progress in descent (no
change in station) is observed over a period of at least 2 hours. It may
be due to one or a combination of several underlying abnormalities like
CPD, malposition (OP), malpresentation, inadequate uterine
contradictions or asynclitism.
DANGERS: Fetal: The fetal risk is increased due to the
combined effects of:
(1) Hypoxia due to diminished uteroplacental circulation,
especially after rupture of the membranes,
(2) Intrauterine infection, (3) Intracranial stress or
hemorrhage following prolonged stay in the perineum
and/or supermoulding of the head, (4) Increased operative
delivery.
Prolonged second stage of labor is often associated with
variable and delayed decelerations . Scalp blood pH
estimations show fetal acidosis. All these result in
increased perinatal morbidity and mortality
Maternal: There is increased incidence of: (1) distress
(2)chorioamnionitis, (3) Postpartum hemorrhage, (4)
trauma to the genital tract—concealed (undue stretching
of the perineal
muscles which may be the cause of prolapse at a later
period) or revealed such as cervical tear, rupture uterus,
(5) increased operative delivery (vaginal instrumental or
difficult cesarean), (6) puerperal sepsis, (7)
subinvolution.
The sum effects of all these lead to increased maternal
morbidity and also increased maternal deaths.
TREATMENT
PREVENTION
 Antenatal or early intranatal detection of the factors likely
to produce prolonged labor (big baby, small women,
malpresentation or position).
 Use of partograph helps early detection.
 Selective and judicious augmentation of labor by low
rupture of the membranes followed by oxytocin drip.
 Change of posture in labor other than supine to increase
uterine contractions, emotional support, avoidance of
dehydration in labor and use of adequate analgesia for pain
relief.
ACTUAL TREATMENT: Careful evaluation is to be done to find

out:
(1) cause of prolonged labor (2) effect on the mother, (3)
effect on the fetus.
In a nulliparous patient, inadequate uterine activity is the
most common cause of primary dysfunctional labor. Whereas
in a multiparous patient, cephalopelvic disproportion (due to
malposition) is the most common cause
Preliminaries: In an equipped labor ward, prolonged
labor is unlikely to occur in modern obstetric practice.
But cases of neglected prolonged labor with evidences
of dehydration and ketoacidosis are admitted not
infrequently to the referral hospitals in the developing
countries. Correction of ketoacidosis should be made
urgently by rapid intravenous infusion of Ringer’s
solution
Definitive treatment:
First stage delay: Vaginal examination is done to verify the
fetal presentation, position and station. Clinical pelvimetry
is done. If only uterine activity is suboptimal, (1)
amniotomy and/or oxytocin infusion is adequate, (2)
effective pain relief is given by intramuscular pethidine or
by regional (epidural) analgesia.
For the management of secondary arrest, especially in
multipara one should be very careful to use oxytocin, (3)
cesarean section is done when vaginal delivery is unsafe
(malpresentation, malposition, big baby or CPD).
Second stage delay—Short period of expectant
management is reasonable provided the FHR (electronic
monitoring) is reassuring and vaginal delivery is
imminent. Otherwise appropriate assisted delivery,
vaginal (forceps, ventouse) or abdominal (cesarean)
should be done. Difficult instrumental
delivery should be avoided.