Abnormal Labor
Jacqueline Perote-Pedroso, M.D.
Maternal Fetal Medicine
OB-GYN Ultrasound
Dystocia
• literally means difficult labor
• First, expulsive forces may be abnormal. For example, uterine
contractions may be insufficiently strong or inappropriately
coordinated to efface and dilate the cervix— uterine dysfunction.
Also, there may be inadequate voluntary maternal muscle effort
during second-stage labor
• Second, fetal abnormalities of presentation, position, or
development may slow labor. Also, abnormalities of the maternal
bony pelvis may create a contracted pelvis
• soft tissue abnormalities of the reproductive tract may form an
obstacle to fetal descent
• Power, Passenger, Passages
Types of Uterine Dysfunction
• Hypotonic uterine dysfunction,
no basal hypertonus and uterine contractions have a normal
gradient pattern (synchronous), but pressure during a contraction is
insufficient to dilate the cervix.
• Hypertonic uterine dysfunction or incoordinate uterine dysfunction
basal tone is elevated appreciably or the pressure gradient is
distorted
more forceful contraction of the uterine midsegment than the
fundus or from complete asynchrony of the impulses originating in
each cornu or a combination of these two
Active Phase Disorders
• Protraction – slowing down
• Arrest – complete cessation of progress
American College of Obstetricians and Gynecologists (2013)
diagnosis of first-stage labor arrest
1. First, the latent phase has been completed, and the cervix is dilated
4 cm or more.
2. a uterine contraction pattern of 200 Montevideo units or more in a
10-minute period has been present for 2 hours without cervical
change.
Second Stage Disorders
• many of the cardinal movements necessary for the fetus to negotiate
the birth canal
• disproportion of the fetus and pelvis frequently becomes apparent
during second stage labor.
• nulliparas was limited to 2 hours and extended to 3 hours when
regional analgesia
• multiparas, 1 hour was the limit, extended to 2 hours with regional
analgesia
Causes of Uterine Dysfunction?
• Epidural
• Chorioamnionitis
• Maternal position during labor
• Birthing position
• Water immersion
Precipitate Labor
• extremely rapid labor and delivery.
• precipitous labor terminates in expulsion of the fetus in < 3 hours
• Maternal Effects and Fetal effects
Partograph
• Shows the progress of labor
• Graph - rate of cervical dilatation and descent in relation to the
duration of labor
• WHO partograph
ALERT line
ACTION line
Partograph
Fetal Station
Cervical Dilatation
Hours Elapsed
WHO Partograph
35 y.o.G3P2 (2012) Pregnancy Uterine 40 weeks, ROT delivered by primary LTCS to a live
baby girl, BW 4.06kg, BL 52cm, AS 8,9, LGA; Arrest in cervical dilatation secondary to
fetopelvic disproportion; Preeclampsia with severe features; Gestational Diabetes Mellitus
diet, controlled; Anemia secondary to acute blood loss secondary to postpartum
hemorrhage, on correction
ROT
ROT
SROM:Clear non foul
smelling amniotic fluid
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35 y.o. G4P4 (3103) Pregnancy uterine 40 weeks, OA, delivered by Low forceps extraction to a live
baby boy, BW 2.9 kg, BL 55cm, AS 8,9 AGA; Previous CS x1 for breech presentation
LOA
SROM: Clear
nonfoul smelling
fluid
OA
0
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20 y.o. G1P1 (1001) Pregnancy Uterine 38 – 39 weeks, LOT, delivered by primary LTCS secondary to CPD to a
live term baby girl, BW 3.11 kg, BL 50 cm, AS 8, 9, AGA; PROM x 74 hours; Bronchial asthma not in acute
exacerbation
LOT
0
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LOT
11
12 13 14
15 16
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21 y.o. G1P1 (1001) Pregnancy Uterine 40 – 41 weeks, ROA, delivered by primary LTCS secondary to CPD to a
live term baby boy BW 3.29 kg, BL 52 cm, AS 8, 9, AGA; Gestational diabetes mellitus, diet-controlled; Dermoid
cyst, left ovary
ROT
ROA
ROA ROA
0
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21 y.o. G1P1 (1001) Pregnancy Uterine 40 – 41 weeks, ROA, delivered by primary LTCS secondary to CPD to a
live term baby boy BW 3.29 kg, BL 52 cm, AS 8, 9, AGA; Gestational diabetes mellitus, diet-controlled; Dermoid
cyst, left ovary
ROT
ROA
0
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ROA ROA
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Passages
Pelvic brim is formed by:
• the sacral promontory behind,
• iliopectineal lines or linea terminais laterally,
• symphysis pubis anteriorly.
• Above the brim >>> false pelvis, which forms part
of the abdominal cavity.
• Below the brim >>> true pelvis.
The sacrotuberous and sacrospinous ligaments complete the greater
and lesser sciatic foraminae
Pelvic Planes
• imaginary, flat surfaces that extend across the pelvis at different
levels.
four planes :
1. The pelvic inlet
2. The plane of greatest diameter
3. The plane of least diameter
4. The pelvic outlet
PELVIMETRY
• Pelvimetry is the assessment of the dimensions &
capacity of adult female pelvis in relation to the birth
of a baby.
• Pelvimetry was heavily used in leading the decision of
natural, operative vaginal delivery or CS.
Types of Pelvimetry
External/indirect pelvimetry
•
•
Measures diameters of false pelvis
Little value, unreliable, no longer used
Internal/ direct pelvimetry
Radiographic pelvimetry
Pelvimetry
• Through vaginal examination
• At first prenatal visit screen for obvious contractions.
• In late pregnancy (preferred)
•
•
•
•
After 37 weeks GA or at the onset of labour
the soft tissues are more distensible
more accurate
less uncomfortable
Pelvic Inlet
1. Palpation of pelvic brim:
• The index & middle fingers are moved
along the pelvic brim.
• Note whether round or angulated, causing
the fingers to dip into a V-shaped
depression behind the symphysis.
2) Diagonal conjugate:
• Measured from the lower border of the
pubis to the sacral promontory using the tip
of the second finger and the point where the
index finger of the other hand meets the
pubis
• Normally 12.5 cm & cannot be reached.
• If it is felt the pelvis is contracted
• True conjugate = diagonal conjugate – 1.5
• Not done if the head is engaged.
The Midpelvis
) Symphysis:
• Height, thickness & curvature
2) Sacrum:
• Shape & curvature
• Concave usually.
• Flat or convex shape may indicate AP constriction throughout the pelvis.
3) Side walls:
• Straight, convergent or divergent starting from the pelvic brim down to the base
of ischial spines.
• Normally almost parallel or divergent
1
4) Ischial spines prominence:
• The ischial spines can be located by
following the sacrospinous ligament to its
lateral end.
• Blunt (difficult to identify at all),
• Prominent (easily felt but not large) or
• Very prominent (large and encroaching on
the mid-plane).
5) Interspinous diameter:
• If both spines can be touched
simultaneously, the interspinous diameter is
9.5 cm i.e. inadequate for an average-sized
baby.
6) Sacrospinous ligament:
• Its length is assessed by placing one finger on the ischial spine & one
finger on the sacrum in the midline.
• The average length is 3 fingerbreadths.
7) Sacrosciatic notch:
• If the sacrospinous ligament is 2.5 fingers, the sacrosciatic notch is
considered adequate.
• Short ligament suggests forward curvature of the sacrum & narrowed
sacrosciatic notch.
Pelvic Outlet
1) Subpubic angle:
• Assessed by placing a thumb next to each inferior
pubic ramus and then estimating the angle at
which they meet.
• Normally, it admits 2 fingers. (90o)
• Angle ≤ 90 degrees suggests contracted
transverse diameter in the midplane and outlet.
2) Mobility of the coccyx.
• by pressing firmly on it while an
external hand on it can determine its
mobility.
3) Anteroposterior diameter of the
outlet:
• From the tip of the sacrum to the
inferior edge of the symphysis.
(>11cm)
4) Bituberous diameter:
• Done by first placing a fist between
the ischial tuberosities.
• An 8.5 cm distance (4 knuckles) is
considered to indicate an adequate
transverse diameter.
Data
Finding
Forepelvis (pelvic brim)
Round.
Diagonal conjugate
≥ 11.5 cm.
Symphysis
Average thickness, parallel to sacrum.
Sacrum
Hollow, average inclination.
Side walls
Straight.
Ischial spines
Blunt.
Interspinous diameter
≥ 10.0 cm.
Sacrosciatic notch
2.5 -3 finger - breadths.
Subpubic angle
2fingerbreadths (90o).
Bituberous diameter
4 knuckles (> 8.0 cm).
Coccyx
Mobile.
Anterposterior diameter of outlet
≥ 11.0 cm.
Adequate Pelvis
Passenger
Assessment of Fetal Size
• Fundic Height
• Mueller Hillis Maneuver
• Biometry
Asynclitism
33 y.o. G2P2 (2002) Pregnancy Uterine 39 to 40 weeks, ROP, delivered by primary LTCS for malposition
(anterior asynclitism) a live term baby girl BW 3.34 kg, BL 50 cm, AS 8, 9 AGA; PROM 8 hours
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FACE
• head is hyperextended so that the occiput is in contact with the fetal
back, and the chin (mentum) is presenting
• Due to complete extension of fetal head
• Presenting diameter(submento-bregmatic)
– 9.5cm
• Same diameter as suboccipito-bragmatic
(vertex) presentation
• Engagement of the fetal head is late &
progress is also slow
Diagnosed by palpating nose, mouth and eyes on vaginal examination
FACE
• include conditions that favor extension or prevent head flexion eq. marked
enlargement of the neck or coils of cord around the neck may cause
extension, anencephaly
• pelvis is contracted or the fetus is very large
• High parity  pendulous abdomen
• In the absence of a contracted pelvis, and with effective labor, successful
vaginal delivery usually will follow.
• Attempts to convert a face presentation manually into a vertex
presentation, manual or forceps rotation of a persistently posterior chin
to a mentum anterior position, and internal podalic version and
extraction are dangerous and should not be attempted.
BROW PRESENTATION
• portion of the fetal head between the orbital ridge and the
anterior fontanel
• Presenting diameter (mento-vertical) – 13.5cm
• Incompatible with a vaginal delivery
• causes of persistent brow presentation are the same as those for face
presentation. A brow presentation is commonly unstable and often
converts to a face or an occiput presentation
• a very small fetus and a large pelvis, labor is generally easy, but with
a larger fetus, it is usually difficult
TRANSVERSE LIE/SHOULDER
• Due to transverse oblique lie of the fetus
• Common causes of transverse lie include:
(1) abdominal wall relaxation from high parity,
(2) preterm fetus,
(3) placenta previa,
(4) abnormal uterine anatomy,
(5) hydramnios,
(6) contracted pelvisDelivery by Caesarean section
• Delay making the diagnosis have risk of
• Cord prolapse
• Uterine rupture
• Diagnosis: Physical Exam
Abdominal and Internal Exam
• Management
Cesarean Section
conduplicato corpore
Compound presentation
Maternal Complications
• Uterine rupture
• Uterine atony
• Increased incidence of operative deliveries
• Fistula Formation
• Pelvic Floor Injury
• Post-partum lower extremity Injury
Perinatal Complications
• Caput succedaneum and molding
• nerve injury
• fractures
• Cephalohematoma
• Mortality
Shoulder Dystocia
Incidence
• Shoulder dystocia is an unpredictable obstetric complication with the
incidence of 0.15% to 2%.
• An increase in the incidence of shoulder dystocia has been recorded
over the last 20 years
• Incidence appears to be increasing as birth weights increase.
Ceska Gynekol 2010 ; 75(4):274-79
Although half of shoulder dystocias occur in infants
weighing less than 4000 gms…. The incidence of
shoulder dystocia is directly related to fetal size.
Definition
• “Difficulty encountered in the delivery of
the fetal shoulders after delivery of the
head.”
• It is the complication of vaginal delivery that
requires additional obstetric manoeuvres to
release the shoulders of the baby.
• Due to impaction of the fetal shoulder
behind the symphysis pubis.
Diagnosis
• One often described feature is the turtle sign which
involves the appearance and retraction of the fetal head
(analogous to a turtle withdrawing into its shell) and the
erythematous, red puffy face indicative of facial flushing.
• This occurs when the baby's shoulder is impacted in the
maternal pelvis
Risk Factors
Remember, many cases of shoulder dystocia
occur with no readily identified risk factors!!!!
ANTEPARTUM FACTORS
•
•
•
•
INTRAPARTUM FACTORS
Maternal Obesity
• Prolonged Second Stage of
Labor
Maternal Diabetes Mellitus
• Oxytocin Induction
Post-term Pregnancy
• Midforceps and Vacuum
Excessive Weight Gain
Extraction
Risk factors
• Fetal macrosomia and maternal diabetes most
strongly associated with shoulder dystocia
• No single risk factor or combination of risk factors
are predictive for which infants will experience
shoulder dystocia
Fetal Complications
• Fetal Fractures • In 18 to 25% of cases
• Erb’s Palsy • Although 80% will resolve by 18 months
• Perinatal Asphyxia – Uncommon
• Brachial plexus injury
• Neonatal Death - Rare
Maternal Complications
• Postpartum Hemorrhage
• Vaginal Lacerations
• Cervical Lacerations
• Puerperal Infection
Management of Shoulder Dystocia
• Individuals who MUST be present in the room if shoulder dystocia is
anticipated or encountered
•
•
•
•
•
Attending physician
Anesthesiologist
Pediatrician
Nursing Staff
“Extra Hands”
Who’s the Boss?
• It is important that the conduct of any shoulder
dystocia be managed by the most experienced
person in the room.
• This individual ( generally the attending physician)
must have the ability to intervene at any time and
should be the only one giving orders.
Preliminary Steps
• Call for help and have the team assembled
• Drain the bladder
• Perform a generous episiotomy
• TAKE YOUR TIME, THIS IN AN EMERGENCY, BUT IT IS NOT A RACE!!!
Prevention
• Prophylactic McRoberts Maneuver
• Prophylactic Cesarean Delivery
Preliminary Measures:
• Gentle
pressure on the fetal vertex in a dorsal
direction will move the posterior fetal shoulder
deeper into the maternal pelvic hollow, usually
resulting in easy delivery of the anterior shoulder.
• Excession angulation (>45 degrees) is to
be avoided.
(
Maneuvers
• McRoberts Maneuver
• Suprapubic Pressure
• Gaskin Maneuver
• Episiotomy
• Woods Maneuver/Rubin Maneuver
• Delivery of posterior shoulder
• Zavanelli Maneuver
• Symphysiotomy
McRobert’s Maneuver
• Marked flexion of the maternal thighs unto the abdomen
• Decreases the angle of pelvic inclination
• Cephalic rotation of the pelvis frees the anterior shoulder
McRobert’s Maneuver
Mazzanti Technique
Key points
• Instruct the mother to stop pushing until
suprapubic pressure has been applied
• Apply direct downward pressure above the
maternal symphysis
– Dislodges the anterior shoulder by pushing it
under the maternal symphysis
• Do not use fundal pressure
Rubin Technique
Key points
• Move to the side of the bed opposite of the infant’s face
• Instruct the mother to stop pushing
• Apply firm pressure on the backside of the infant’s anterior
shoulder and shove in the direction of the infant’s face
– Decreases shoulder to shoulder diameter
• Note: Applying pressure in front of the anterior shoulder and shoving in the
opposite direction of the infant’s face increases the shoulder to shoulder
diameter up to 2 cm
Suprapubic Pressure
• Moderate suprapubic pressure is often the
only additional maneuver necessary to disimpact
the anterior fetal shoulder. Stronger pressure can
only be exerted by an assistant.
(Gabbe, et al., 1986)
Woods’ Corkscrew Maneuver
• Woods' corkscrew
maneuver. The shoulders
must be rotated utilizing
pressure on the scapula and
clavicle.
• The head is never rotated.
(B.Harris, Shoulder dystocia, Clinical Obstetrics and Gynecology, 1984; 27:106.)
Woods’ Corkscrew Maneuver
• Delivery may be facilitated by
counterclockwise
rotation of the anterior shoulder
to the more
favorable oblique pelvic
diameter, or clockwise rotation
of the posterior shoulder.
• During these maneuvers,
expulsive efforts should be
stopped and the head is
never grasped !!
Delivery of the Posterior Arm
• To bring the fetal wrist
within reach, exert
pressure with the index
finger at the antecubital
junction.
Delivery of the Posterior Arm
• Sweep the fetal
forearm down over the
front of the chest.
Delivery of the Posterior Arm
• If less invasive maneuvers fail to
affect this impaction, delivery should
be facilitated by manipulative
delivery of the posterior arm by
inserting a hand into the posterior
vagina and ventrally rotating the arm
at the shoulder with delivery over the
perineum.
When All Else Fails...
• The Rubin Maneuver
• The Chavis Maneuver
• The Hibbard Maneuver
• Fracture of the Clavicle / Cleidotomy
• The Zavanelli Maneuver
• Symphysiotomy
The Rubin Maneuver
• Step 1: The fetal shoulders are rocked from side to side by applying
force to the maternal abdomen.
• Step 2: If step one is not successful, push the presenting fetal
shoulder toward the chest. This will often cause abduction of both
shoulders and create a smaller shoulder to shoulder diameter.
The Chavis Maneuver
• Described in 1979.
• A “shoulder horn” consisting of a concave blade with a narrow handle
is slipped between the symphysis and the impacted anterior shoulder.
• This used like a shoe-horn as a lever where the symphysis is the
fulcrum.
The Hibbard Maneuver
• Release of the anerior shoulder is
initiated by firm pressure against
the infant's jaw and neck in a
posterior and upward direction. An
assistant is poised, ready to apply
fundal pressure after proper
suprapublic pressure
• As the anterior shoulder slips free,
fundal pressure is applied, and
pressure against the neck is shifted
slightly toward the rectum.
Proper suprapubic pressure is
continued.
The Hibbard Maneuver
• Continued fundal and
suprapublic pressure
results in an upwardinward rotation of the
newly freed anterior
shoulder and a further
descent in a position
beneath the pubic
symphysis.
The Hibbard Maneuver
• As a result of the previous maneuvers, the
transverse diameter of the shoulders is reduced.
• Lateral (upward) flexion of the head releases the
posterior shoulder into the hollow of the sacrum.
Fracture of the Clavicle
• The anterior clavicle is pressed against the ramis of the pubis.
• Care should be taken to avoid puncturing the lung by angling the
fracture anteriorly.
• Theoretically, a fracture of the clavicle is less serious than a brachial
nerve injury and often heals rapidly.
The Zavanelli Maneuver
• First described in 1988
• Consists of cephalic replacement and then cesarean delivery.
• Mixed reviews in the literature.
... Don’t Even Think About It...
• Symphysiotomy is a dangerous procedure with substantial risk to
maternal health and well being.
• It is difficult to justify this procedure for shoulder dystocia in modern
medicine.
Complications Associated with
Symphysiotomy
• Vesicovaginal Fistula
• Osteitis Pubis
• Retropubic Abscess
• Stress Incontinence
• Long Term Walking Disability / Pain
• Although shoulder dystocia represents a catastrophic event in
obstetrics, a well-reasoned plan of action with adequate support and
skilled personnel can reduce fetal morbidity.
• Proper patient selection and awareness of risk factors for shoulder
dystocia can also reduce morbidity.
Can Cesarean Sections for Suspected Macrosomia
Reduce the Rates of Shoulder Dystocia?
• No
• Sensitivity of clinical estimates of BW > 4500 gms is only 20%
• USG is not very accurate at extremes of EFW
• Most cases of shoulder dystocia occur in infants of average weight
• The incidence of birth trauma in large infants is not trivial
• (2.5% with BW > 4500 gms)
Top Reasons for Successful Claims Against Obstetricians in
Cases of Shoulder Dystocia
• Inappropriate obstetrical delivery notes
• Absence of delivery notes
• Failure to document the dystocia
• Failure to document use of McRobert’s maneuver
• Lack of prenatal documentation or follow-up of
• Abnormal or borderline GTT
• Unexpected large maternal weight gain.
Harvard Risk Management Foundation (1994)
www.rmf.org
Things To Do After Dystocia Occurs
• Check for and treat reproductive tract injuries
• Pediatric neurology and neonatology consultation
• Document a detailed delivery note, including maneuvers
used
• Explain the occurrence of dystocia to the parents of the
infant
• Do not finger-point
• Be truthful, but avoid discrepancies in notes by doctors,
midwives and nurses.
Harvard Risk Management Foundation (1994)
www.rmf.org