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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
Functional Divisions of Labor
• Preparatory Division
• Dilatational 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
Functional Divisions of Labor
• Preparatory Division
• 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
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
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
Protraction Disorders
• Protracted Active Phase• Protracted Descent• Etiology :
– Malposition– Excessive sedation / conduction analgesia– Cephalopelvic disproportion
• Management:– Augment of labor– CS = 28% have CPD
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
Arrest Disorders• Criteria before diagnosing Arrest disorders:
– Latent phase completed (Cx > 4 cms)– Intensity of Uterine contractions > 200 MvU x 2 h
• Etiology:– Cephalopelvic disproportion– Hypotonic uterine contraction– Malposition– Excessive sedation / anesthesia
• Management:– CS– Augment labor
• “2-hour rule” for diagnosis of arrest in active phase of labor has recently been challenged
• 542 women included where CS delivery was not performed for labor arrest until there were at least 4 hours of a sustained uterine contraction of >200montivedeo units or a minimum of 6 hours oxytocin augmentation if the contraction pattern could not be achieved
• 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
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 Latent Phase
Prolonged Deceleration PhaseFailure of DescentProtracted DescentArrest 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– Expulsive powers:
• Uterine dysfunction, or• inadequate voluntary muscle effort
• PASSENGER– Presentation, Position, or Development of the Fetus
• PASSAGE– Maternal Bony Pelvis (Pelvic Contraction)– Soft Tissues of the Reproductive Tract
Normal Uterine Contractions
Parameter Latent Phase Active Phase to
Second Stage
Frequency / Interval
3-5 mins 2-3 mins
Duration 30 – 40 secs 40 – 60 secs
Intensity Mild to moderate
Moderate - strong
Methods to Quantify Uterine Activity
palpation
external tocodynamometry
internal uterine pressure sensors
Normal Uterine Contractions
• Characterized by a gradient of myometrial activity: greatest and lasting longest at the fundus (fundal dominance) & diminishing toward the cervix
UTERINE DYSFUNCTION
Hypotonic Uterine Dysfunction
• More common
• No basal hypertonus
• Uterine contractions have a normal pressure gradient pattern (synchronous)
• IUP < 25 mmHg insufficient to dilate cervix
UTERINE DYSFUNCTION
Hypertonic Uterine Dysfunction
• Also called incoordinate uterine dysfunction
• Either basal tone is elevated or pressure gradient is distorted by contraction of the midsegment of the uterus with more force than the fundus or by complete asynchronism or a combination of both
CAUSES OF UTERINE DYSFUNCTION
• Epidural analgesia
• Chorioamnionitis
• Maternal position during labor
• Birthing position in 2nd stage labor
William’s Obstetrics, 21st ed.