Ob - Dystocia 2

DYSTOCIA

ANDREW ROULDAN B. BUIZON, M.D., FPOGS, FSGOP

Assistant Professor

De La Salle University – Health Sciences Institute

DYSTOCIA

• Literally means “Difficult Labor”

• Characterized by Abnormally SLOW Progress of Labor

Overview of the lecture

I – Normal and Abnormal Labor

II – Causes of Dystocia

III – Complications of Dystocia

Factors that affect Labor• Power

– First stage: uterine contractions– Second stage: uterine contractions + intra-

abdominal pressure

• Passenger – Fetal Attitude, Presentation, Position– Ability to adapt through Passage

• Passage– Birth canal

• *For Normal Labor to take place – Normal 3P’s

Prognosis for Vaginal Delivery

• Power – force of uterine contractions

• Passenger:– Presentation and Position – Size of fetal head– Adaptability of fetal head

• Passage – size and shape of maternal bony pelvis

Stages of Labor

First* - regular uterine contractions fully

Second*- full cervical dilatation delivery baby

Third - delivery of baby placental delivery

“Fourth” - immediate postpartum

*Stages concerned with Dystocia

First Stage of Labor

• Latent Phase

• Active Phase– Acceleration Phase

• Predictive of outcome of labor

– Phase of Maximum slope• Measure of efficiency of the “machine”

– Deceleration Phase• Reflective of fetopelvic relationship

History of the Partograph

Functional Divisions of Labor

• Preparatory Division

• Dilatational Division

• Pelvic Division

Preparatory Division

• Latent Phase and Acceleration Phase

• Major event – cervical ripening– Softening: changes in ground substance– Effacement: obliteration of cervical canal

• Cervical dilatation – minimal

• Fetal descent – minimal to absent

• Sensitive to sedation and conduction analgesia

Preparatory Division




• Pelvic Division

Dilatational Division

• Phase of Maximum Slope

• Major Event – cervical dilatation

• Cervical Dilatation – most rapid rate

• Fetal Descent – minimal

• Unaffected by sedation and conduction analgesia

Dilatational Division




• Pelvic Division

Pelvic Division

• Deceleration Phase to Second Stage of labor

• Major Event – cardinal movements

• Cervical Dilatation – rapid rate

• Fetal Descent – maximal

• Minimally affected by sedation but ‘bearing down’ effort largely affected by conduction analgesia

Pelvic Division

Cervical Dilatation and Fetal Descent

• The only characteristics of the parturient useful in assessing labor & its progression

• Time vs. Cervical Dilatation – sigmoid curve

• Time vs. Fetal descent – hyperbolic curve

Mechanical Forces of Labor

• Factors responsible for progression and completion of each stage

• First stage:– Uterine power– Cervical resistance– Forward pressure of the fetal head

• Second stage:– Mechanical relationship between fetal head

and pelvic capacity

Diagnosis of Labor

True Labor False Labor

Regularity (+) (-)

Frequency > 1 / 10 min no pattern

Duration > 10 seconds variable

Intensity increasing no pattern

Effect of

walking aggravates no effect

Criteria for Diagnosis of Labor

1. Documented uterine contractions (at Least once in 10 minutes, or 4 in 20 min.) In the form of direct observation or Electronically using a cardiotocogram

2. Documented progressive changes in cervical dilatation and effacement, as Observed by one observer

3. Cervical effacement of greater than 75-80%

4. Cervical dilatation of greater than 3 cm

Diagnosis of Normal Labor

LABOR PATTERN

NULLIPARA MULTIPARA

Latent Phase < 20 hours < 14 hours

Cervical Dilatation

> 1.2 cm/hr > 1.5 cm/hr

Fetal Descent > 1 cm/hr > 2 cm/hr

Diagnosis of Abnormal LaborLABOR

PATTERNNULLIPARA MULTIPARA

Prolongation Disorder

Latent Phase > 20 hours > 14 hours

Deceleration Phase > 3 hours > 1 hour

Protraction Disorder

Dilatation < 1.2 cm/hr < 1.5 cm/hr

Descent < 1 cm/hr < 2 cms/hr

Arrest Disorder

No Dilatation > 2 hours > 2 hours

No Descent > 1 hour > 1 hour

Prolonged Latent Phase

• It is the only disorder diagnosable in the Preparatory Division of Labor

• Criteria:– Nulli > 20 hrs– Multi > 14 hrs


08 12 16 20 24 28

Hours of Labor

2

4

6

8

10

Cer

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cm)

Etiology of Prolonged Latent Phase

• False Labor = 50% of the time

• Excessive sedation

• Unfavorable cervix (thick, uneffaced, closed)

• Uterine / Labor dysfunction

• Unknown

Management ofProlonged Latent Phase

• Therapeutic Rest – if no C/I to delay for 6-10 hrs– Strong sedatives– Upon waking, 85% = enter active phase 15% = false labor

• Amniotomy – will not accelerate latent phase

• Caesarean section– Not usually done unless with indications









Arrest Disorder



Protraction Disorders of LaborD

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A

B

Protraction Disorders

• Protracted Active Phase• Protracted Descent• Etiology :

– Malposition– Excessive sedation / conduction analgesia– Cephalopelvic disproportion

• Management:– Augment of labor– CS = 28% have CPD









Arrest Disorder



Arrest DisordersD

ilata

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A

B

C

D

Arrest Disorders

• Criteria before diagnosing Arrest disorders:– Latent phase completed (Cx > 4 cms)– Intensity of Uterine contractions > 200 MvU x 2 h

• “2-hour rule” for diagnosis of arrest in active phase of labor has recently been challenged

• 542 women included where CS delivery was delayed until there were at least 4 hours of a sustained uterine contraction of >200 MvU or a minimum of 6 hours oxytocin augmentation if the contraction pattern could not be achieved

Arrest Disorders

• Protocol resulted in high rate of vaginal delivery (92%) w/ no severe adverse maternal or fetal outcomes

• “Thus extending the minimum period of oxytocin augmentation for active arrest from 2 hours to 4 hours appears effective”

ACOG Practice Bulletin, Compendium 2004

Arrest Disorders

• Etiology:– Cephalopelvic disproportion– Hypotonic uterine contraction– Malposition– Excessive sedation / anesthesia

• Management:– CS = 52% have CPD– Augment labor, if no CPD

Management of Abnormal LaborLabor pattern Preferred

TreatmentExceptional Treatment

Prolongation Disorders

Latent Phase Bed rest Augment / CS

Protraction Disorders

Dilatation Expectant / Support

CS for CPD /

AugmentDescent

Arrest Disorders

Prol Decel Augment if no CPD

Rest if exhausted

2o Arrest of Dil

Arrest of Descent CS if + CPD CS

Failure of descent

Abnormal Labor (Based on Friedman’s curve)

Arrest in Cervical DilatationProtracted Active Phase


Prolonged Deceleration PhaseFailure of DescentProtracted DescentArrest of Descent

Spontaneous rupture of membranes

Oxytocin

Normal Labor Pattern

AMNIOTOMY

OXYTOCIN

Arrest in Cervical Dilatation

AMNIOTOMY

OXYTOCIN

Prolonged Deceleration Phase

AMNIOTOMY

OXYTOCIN

Arrest of Descent





DYSTOCIA - Abnormal Labor

• Other names: Dysfunctional labor, Ineffective labor, Failure to progress

Worldwide - Accounts for 43% of all primary cesarean sections

Philippines - it accounts for 38.85% Textbook of Obstetrics,

2002

Risk Factors for Dystocia

• Associated w/ longer 2nd stage- epidural analgesia

- occiput posterior position

- longer 1st stage of labor

- nulliparity

- short maternal stature

- birthweight

- high station at complete cervical dilatationACOG Practice Bulletin

Compendium 2004

DYSTOCIA - Abnormal LaborThree categories causing Dystocia: (Abnormalities of 3Ps)

• POWERS– Uterine contractility– Expulsive Powers (“Bearing down” in the 2nd

Stage of Labor)

• PASSENGER– Presentation, Position, or Development of the Fetus

• PASSAGE– Maternal Bony Pelvis (Pelvic Contraction)– Soft Tissues of the Reproductive Tract

Physiology of Uterine Contractions

Methods to Quantify Uterine Activity

palpation

external tocodynamometry

internal uterine pressure sensors


Uterine contractions characterized by a gradient of myometrial activity:

1. Fundal Dominance• Onset, intensity & duration• Cornual area – ‘pacemaker’ of the uterus• Greatest & longest activity at the fundus• Diminishing towards the cervix


2. Triple Descending Gradient

• Gradient of contractions diminishes from upper to lower segment

• Upper uterine segment retracts about the fetus as the fetus descends through birth canal


• Uterine activity – Montevideo units (MU)– MU = Intensity x Frequency / 10 minutes

• Intensity (intrauterine pressure) = peak contraction

minus baseline contraction • 200 MU = adequate uterine contractions

UTERINE DYSFUNCTION

CLINICAL CRITERIA HYPOTONIC HYPERTONIC

Occurrence 4 % 1 %

Phase of Labor Active Latent

Clinical Symptoms Painless Painful

Fetal Distress Late Early

Reaction to Oxytocin Favorable Unfavorable

Value of Sedation Little Great

Gradient Pattern of Activity

Normal but decreased

Abnormal

UTERINE DYSFUNCTION

Causes of Hypotonic Uterine Dysfunction

• Uterine overdistention

• Grandmultiparity

• Sedation

• Regional anesthesia

HYPERTONIC UTERINE DYSFUNCTION

Also called ‘incoordinate’ uterine dysfunction

Causes:

• Contraction uterine midsegment

• Asynchrony of impulses originating from each cornu

UTERINE DYSFUNCTION

REMEMBER, normally there is:

• LOW uterine activity in ‘Latent phase of labor

• HIGH “ “ ‘Active “ “

So that, if there is:

• HIGH uterine activity in Latent phase of labor

=> HYPERTONIC uterine dysfunction

• LOW uterine activity in Active phase of labor

=> HYPOTONIC uterine dysfunction

CAUSES OF UTERINE DYSFUNCTION

A. Epidural analgesia• Lengthens both 1st and 2nd stage of labor• Slows down rate of fetal descent

B. Chorioamnionitis

C. Maternal position during labor• Uterus contracts more frequently with less

intensity in supine vs. lateral decubitus position• Uterus contracts with more frequency and

intensity in sitting or standing position

William’s Obstetrics, 21st ed.

TREATMENT OF HYPOTONIC UTERINE DYSFUNCTION

• Ascertain parturient is in active labor & no CPD:

– Cervix > 4 cms– Clinical pelvimetry is adequate in all levels– Presenting part is occiput and engaged

• Oxytocin stimulation


Oxytocin effect uterine activity

• cervical change• fetal descent

avoid uterine hyperstimulation &/or development of non-reassuring fetal heart status


Oxytocin should be DISCONTINUED• If uterine contractions persist >5 in a 10-

minute period or 7 in a 15-minute period• If the contractions LAST LONGER than 60-

90 seconds• FHR pattern becomes non-reassuring

William Obstetrics 21st edition

Complications of Overinfusion of Oxytocin

hypotension

tachycardia

water retention

Hyperstimulation

Uterine rupture

Fetal distress

TREATMENT OF HYPERTONIC UTERINE DYSFUNCTION

• Characterized by uterine pain out of proportion to intensity of contractions and in effacing & dilating the cervix

• Placental abruption must always be considered

• Fetal distress (+) – CS

(-) - sedation

The Passenger

The Fetus

Position

Presentation

Development

The Passenger• Normal Position – Occiput anterior

• Malpositions:– Persistent Occiput transverse (POT)– Persistent Occiput posterior (POP)

The Passenger• Normal Presentation – Vertex / Cephalic

• Malpresentations:– Brow – Face– Breech– Transverse

• Fetal attitude – relationship bet fetal head & body– Occiput = completely flexed

– Sinciput = partially flexed

– Brow = partially extended

– Face = completely extended

The Passenger• Etiology of deflection attitudes – factors

that favor extension or prevent head flexion:– Neck masses– Anencephaly– Large babies– Cord coils– Contracted pelvis– Pendulous abdomen

The Passenger – Fetal Head Diameters

ATTITUDE PRESENTING DIAMETER

DENOMINATOR

Flexion* Suboccipitobregmatic (SOB) = 9.5 cm

Occiput

Military** Occipitofrontal

(FO) = 11.5 cm

Occiput

Partial Extension**

Occipitomental

(MO) = 12.5 cm

Forehead (Brow)

Complete Extension*

Submentobregmatic

(SMB) = 9.5 cm

Chin / Mentum (Face)

* Vaginal delivery** Unstable / transient presentation – dystocia high

BROW PRESENTATION

• Head is partially extended

• Midway between full flexion & extension

• Rarest presentation

• Longest presenting diameter = 12.5 cm

• Unstable/transient – converts to Face or Occiput presentation

BROW PRESENTATION - Diagnosis

• Abdominal Exam – > ½ of head above symphysis pubis, – Since OM, Vaginal delivery not possible– Leopold’s Maneuver 2 & 3:

• Cephalic prominence same side as fetal back• Occiput and chin palpable

– Occiput palpable at higher level than Sinciput• Occuiput = Posterior fontanel• Sinciput = anterior fontanel

BROW PRESENTATION - Diagnosis

• Vaginal examination– Anterior fontanel– Frontal sutures– Orbital ridges– Eyes– Root of nose

BROW PRESENTATION – Three possible outcomes during course of Labor:

Possible outcome

Mechanism Manner of Delivery

Vertex if head flexes Vaginal

Face if head completely extends

Vaginal

Persistent if no change in position

CS

FACE PRESENTATION

• Fetal head is fully extended / hyperextended• Occiput in contact w/ fetal back, chin presents• Abdominal exam:

– groove felt bet Occiput & Fetal Back

• Vaginal exam:– Distinct facial features– Sinciput & occiput not palpable

• Etiology:– Any factor that favors extension or prevents

flexion (e.g. Anencephaly)

FACE PRESENTATION – Course of Labor

• Chin / mentum anterior:– Expect vaginal delivery -– CS if obstructed labor

• Chin / mentum posterior:– Vaginal delivery possible only if Internally Rotate

anteriorly– Cause of obstructed labor: fetal brow (bregma)

pressed against maternal symphysis pubis – Short neck cannot span the curvature of sacrum

BREECH PRESENTATION

TYPE THIGHS KNEES SACRUM FEET

Complete Flexed Flexed + _

Incomplete (Footling)

Flexed Flexed _ +

Frank Flexed Extended + _

BREECH PRESENTATION

• Leopold’s Maneuver:

• Vaginal Examination:– Ischial Tuberosities– Anus– External Genitalia– Sacrum – Feet

BREECH PRESENTATION

• Possible Etiologies:– Prematurity– Uterine relaxation / Multiparity– Multiple pregnancy– Hydramnios– Oligohydramnios– Hydrocephalus– Anencephaly– Uterine anomalies / tumor– Placente Previa– Habitual breech

BREECH PRESENTATION

• Antenatal Period:– External version may be attempted

• Standard of Care:– Planned CS – to reduce perinatal M & M– Vaginal - In advanced labor of imminent delivery

• Frank / complete• Spontaneous• Partial BE• Total BE

BREECH PRESENTATION

MATERNAL FACTORS FETAL FACTORS

•Pelvic Contraction•Delivery is indicated – patient not in labor•Uterine dysfunction•Lack of Experience Operator

•Large fetus•Hyperextended head “stargazing breech”•Healthy preterm fetus where delivery is indicated•Severe IUGR

Previous Perinatal Death/ Birth Trauma

BREECH PRESENTATION

• Complications– Perinatal M & M – preterm birth, birth trauma,

congenital anomalies– Low Birth Weight – prematurity, IUGR– Prolapsed cord – small fetus, fetus not in

frank breech– Placenta Previa– Uterine anomalies / Tumors

TRANSVERSE PRESENTATION

• Long axis of fetus perpendicular to mother• NO MECHANISM OF LABOR, always CS• Abdomen: SQUAT UTERUS

– Usually wide – Fundus only slightly above umbilicus

• Leopold’s Maneuver: – 1 : empty– 2 : fetal back readily identified

• If anteriror: hard resistant plane• If posterior: irregular nodulations (FSP)

TRANSVERSE PRESENTATION• Vaginal examination:

– Palpate acromion and hands– “Gridiron” – can feel the ribs

• Etiology:– Lax abdominal wall - allows uterus to fall forward, to be

deflected away from long axis of birth canal into an Oblique or Transverse Position

– Prematurity– Placenta previa – Contracted pelvic– Tumor previa– Multiple pregnancy– Fetal uterine anomalies– polyhydramnios

TRANSVERSE PRESENTATION –

Course of Labor• Neglected Transverse Lie

– Prolonged ROM– Stretched / thinned out LUS– Intrauterine infection– Fetal impaction– Prolapsed cord / arm– Dead baby

TRANSVERSE PRESENTATION –

Management• It’s a serious malpresentation

• Management should not be left to nature

• Spontaneous vaginal delivery impossible

• Must deliver by CS immediately





MATERNAL COMPLICATIONS• Hemorrhage & Shock – uterine atony

• Intrapartum infection – ascending type: chorioamnionitis, decidua, chorionic vessels, bacteremia, sepsis

• Uterine rupture – progressive thinning out of LUS in prolonged labor, esp high parity & previous surgery

• Fistula formation – presenting part wedged into pelvic inlet during prolonged labor, tissues of birth canal bet it & pelvic wall subjected to pressure, ischemia, necrosis– Fistula: two cavities joined together (e.g.

rectovaginal or vesicovaginal fistulae)

MATERNAL COMPLICATIONS

• Postpartum lower extremity injury:– Foot drop:

• common peroneal n. + LS plexus or sciatic n.– Inappropriate leg positioning in stirrups– Resolve w/in 6 months postpartum

• Pelvic floor injury:– Directly to pelvic floor m. or their nerve supply

FETAL COMPLICATIONS

• Caput succedaneum:– Soft tissue / scalp edema of most dependent

portion of fetal head– Overlies the periosteum, cross over periosteal

limitations

• Cephalhematoma:– Subperiosteal hemorrhage– Confined by periosteal limits

FETAL COMPLICATIONS – Nerve Injuries

• Spinal injury – overstretching with hemorrhage

• Brachial plexus – – Duchenne / Erb paralysis: (Upper roots)

• Deltoid, infraspinatus, flexor m of forearm• Entire arm fall limply close to side of the body,

forearm extended & internally rotated • Function of hand retained• Excesssive lateral traction upon head, sharply

flexing head toward one of shoulders

– Klumpke paralysis: (Lower roots)• Paralysis of the hand

Ob - Dystocia 2

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