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.