NORMAL LABOR AND

DELIVERY

WHAT IS LABOR?

From the Latin word labor: “troublesome effort or suffering

parturire: “to be ready to bear youngpartus: “to produce”

WHAT IS LABOR? A physiologic process that begins with

the onset of rhythmic contractions which brings about changes in the biochemical connective tissue resulting in gradual effacement and dilation of the cervix and ends with expulsion of the product of conception

CRITERIA FOR THE DIAGNOSIS OF LABOR Uterine Contractions (at least 1 in 10

mins or 4 in 20 mins) by direct observation or electronically

Documented progressive changes in cervical dilation and effacement

Cervical effacement of >70-80%

Cervical Dilation >3 cm

TRUE LABOR VS. FALSE LABOR

TRUE LABOR FALSE LABOR

Regular Contractions Irregular Contractions

Decreasing intervals (shortened)

Irregular and long intervals

Increasing intensity Same intensity or go away spontaneously

Lower abdomen and low back pain

Lower abdomen discomfort

Cervical Dilation No cervical change or cervix does not dilate

PROGRESS OF LABOR 12-14 hours: first delivery 6-hours: succeeding deliveries Cervical Dilatation: opening of the

cervix Cervical Effacement: shortening of

the cervix and thinning of the cervical walls 0%: normal100%: completely thinned

LABOR SUCCESS Depends on:

Power

Passenger

Passageway

PASSENGER Fetal Lie

Longitudinal Lie

Transverse Lie

Oblique Lie

PASSENGER Fetal Presentation

Compound Presentation

PASSENGERCephalic Presentation

Vertex Sinciput Brow Face (SOB)-9.5cm (OF)-11.5cm (OM)-12.5cm (SMB)-9.5cm

Breech Presentation Complete Breech Frank Breech Incomplete Breech

Single Footling BreechDouble Footling Breech

PASSENGER Fetal Attitude or Posture

Head flexed Chin close to chest Extremities close to the body Back curved

Fetal Position: chosen portion of the fetal presenting part Occiput – in cephalic presentation Sacrum – breech presentation Chin/mentum – face presentation Acromion/scapula – shoulder presentation

Cephalic PresentationOcciput anterior (OA)Right Occiput Anterior(ROA)Left Occiput Anterior(LOA)Right Occiput Transverse (ROT)Left Occiput Transverse(LOT)Right Occiput Posterior (ROP)Left Occiput Posterior(LOP)Occiput Posterior(OP)

Breech PresentationSacrum Anterior (SA)Left Sacrum Anterior (LSA)Right Sacrum Anterior (RSA)Right Sacrum Transverse (RST)Left Sacrum Transverse (LST)Right Sacrum Posterior (RSP)Left Sacrum Posterior (LSP)Sacrum Posterior (SP)

PASSENGER Fetal Station: degree of descent of the

presenting part of the fetus from the ischial spines

PASSENGER Number of fetuses

Presence of fetal anomalies

Fetal size

PASSAGEWAY Consists of the bony pelvis and soft

tissues of the birth canal

Small pelvic outlet can result in cephalopelvic disproportion

Pelvimetry: for assessment

PELVIMETRY

DIAGNOSIS OF FETAL PRESENTATION Leopold’s Maneuver Internal Examination Auscultation Imaging Studies

MECHANISM OF LABOR Involves the cardinal movements of

labor:Engagement DescentFlexion Internal rotationExtensionExternal rotationexpulsion

Positional changes in the presenting part of the fetus

MECHANISM OF LABOR: ENGAGEMENT

Passage of the widest diameter of the fetal presenting part below the plane of the pelvic inlet

Asynclitism: due to lateral inclination of the fetal headAnterior Asynclitism (Naegele’s Obliquity)– Sacrum Posterior Asynclitism (Fritzmann’s Obliquity) –

Symphisis Pubis

MECHANISM OF LABOR: DESCENT Pressure of the amniotic fluid Direct pressure of the fundus upon the

breech with contractions Bearing down efforts of maternal

abdominal muscles Extension and straightening of the fetal

body

MECHANISM OF LABOR: FLEXION Resistance of the birth canal on descent Shorter suboccipitobregmatic

diameter(9.5 cm)

MECHANISM OF LABOR: INTERNAL ROTATION Descent will not occur without it Sagittal suture is now oriented antero-

posteriorly (occiput is anteriorly oriented)

MECHANISM OF LABOR: EXTENSION Head up in extension 2 forces:

Force exerted by the fundusForce exerted by the resistance of the

pelvic floor and the symphysis pubis, anteriorly

MECHANISM OF LABOR:EXTERNAL ROTATION The head back to its original position One shoulder is anterior behind the

symphysis pubis and the other is posterior

MECHANISM OF LABOR:EXPULSION Almost immediately after external

rotation The perineum thins out As the shoulder passes out, the rest of

the body follows

4 STAGES OF LABOR 1ST STAGE: onset of labor until full cervical

dilation (Latent and Active Phase)

2ND STAGE: from full cervical dilation of 10 cm until delivery of the baby

3RD STAGE: from delivery of the baby up to the delivery of the placenta

4TH STAGE: the next 2 hours following the delivery of the placenta.

3 FUNCTIONAL DIVISIONS OF LABOR Preparatory Division

Latent PhaseAcceleration Phase

Dilatational DivisionPhase of Maximum Slope

Pelvic DivisionDeceleration PhaseSecond Stage concurrent with the phase of

maximum slope

2 PHASES OF CERVICAL DILATION Latent Phase

Active PhaseAcceleration PhasePhase of Maximum SlopeDeceleration Phase

ASSESSMENT OF A PATIENT IN LABOR

ASSESSSMENT Complete history and PE Abdominal Exam Pelvic Exam (Speculum Exam) Internal Examination

Cervical dilation and effacementPosition of the cervixCervical dilation and effacementFetal StationStatus of the fetal membrane

ROM Character of fluid

MANAGEMENT OF THE STAGES OF

LABOR

1ST STAGE OF LABOR Vital Signs Uterine Contractions Cervical Changes Fetal Heart Tones

1ST STAGE OF LABOR Induction of Labor: an intervention

designed to artificially initiate contractions leading to progressive dilation and effacement of the cervix and birth of the baby (RCOG,2002)Confirmation of ParityConfirmation of Gestational AgePresentationBishop’s ScoreUterine ActivityNon stress Test

BISHOP’S PREINDUCTION CERVICAL SCORE SYSTEM

FACTOR 0 1 2 3

Cervical Dilation (in cm)

Closed 1-2 3-4 >=5

Cervical Effacement (%)

0-30 40-50 60-70 >80

Station -3 -2 -1 +1, +2

Cervical Consistency

Firm Medium soft

Cervical Position

posterior midposition Anterior

1ST STAGE:INDUCTION OF LABOR

It should only be implemented on a valid indication (Level I, Grade C) Gestational HTN Pre eclampsia, eclampsia Prelabor rupture of the membranes Maternal medical indications Gestational >= 41 1/7weeks Evidence of fetal compromise Intraamniotic infection Fetal demise Logistic factors for term pregnancy

1ST STAGE:INDUCTION OF LABOR

Contraindications: Malpresentation Absolute cephalopelvic disproportion Placenta Previa Previous major uterine surgery or classical CS Invasive carcinoma of the cervix Cord presentation Active genital herpes Gynecological, obstetrical, or medical conditions

that prelude vaginal birth Obstetrician’s convenience

1ST STAGE:INDUCTION OF LABOR (METHODS)

OXYTOCIN Oxytocin augmentation is a major intervention and

should only be implemented on a valid indication. (Level I, Grade C)

When induction of labor is undertaken with oxytocin, the recommended regimen is a starting dose of 1-2 mU/min and is increased at intervals of 30 mins or more. The minimum dose should be used and this should be titrated against uterine contractions aiming for maximum of 3-4 contractions every 10 mins. (RCOG, Grade C)

Regular observations of uterine contractions and FHT should be recorded every 15 to 30 minutes and with each incremental increase of Oxytocin.

1ST STAGE:INDUCTION OF LABOR (METHODS) MEMBRANE SWEEPING/STRIPPING

Increases local production of prostaglandins

AMNIOTOMYArtificial rupture of the membranes

1ST STAGE:FAILED INDUCTION Continued lack of progression into the

active phase

Nulliparous women could safely remain in the latent phase for 12 hours

It is not reasonable to allow up to 18 hours of latent labor before recommending CS.

2ND STAGE OF LABOR Duration:

50 minutes: Nullipara20 minutes: Mutlipara

Fetal Heart Tones: every 15 minutes Ritgen Maneuver

2ND STAGE OF LABOR Molding – fusion of the parietal bones

Caput - swelling

3RD STAGE OF LABOR Placental Separation

Calkin’s SignSudden gush of bloodUterus rises in the abdomen(tilted)The umbilical cord rises

Mechanism of Placental SeparationDuncan: peripheral separationSchulze: central separation

3RD STAGE OF LABOR: USE OF EPISIOTOMY AND REPAIR

Lacerations of the Birth Canal1st degree: fourchette, perineal skin, vaginal

mucosa2nd degree: above + fascia and muscles of the

perineum3rd degree: above + anal sphincter4th degree: above + rectal mucosa

3RD STAGE: USE OF EPISIOTOMY AND REPAIR Purpose: to facilitate the 2nd stage of labor

to improve maternal and neonatal outcome Maternal Benefit

Reduced risk of perineal trauma, subsequent floor dysfunction and prolapse, urinary and fecal incontinence, and sexual dysfunction

Fetal Benefit Shortened 2nd stage of labor

Timing Too early: increased blood loss Late: laceration may not be prevented

3RD STAGE: USE OF EPISIOTOMY AND REPAIR

IndicationsExpedite delivery in the 2nd stageWhen spontaneous laceration is likelyMaternal or fetal distressAssisted forceps deliveryLarge BabyMaternal exhaustion

3RD STAGE: USE OF EPISIOTOMY AND REPAIR Kinds of Episiotomy

3RD STAGE: USE OF EPISIOTOMY AND REPAIR

3RD STAGE: USE OF EPISIOTOMY AND REPAIR Routine vs. Restrictive Episiotomy

Episiorrhaphy: repair of lacerationSuture Materials and Technique

2 layered closure can improve postpartum pain and healing complications vs a 3 layered closure.

There is good evidence to support the use of Fast Absorbing Polyglactin 910 as a material of choice for perineal closure. (Level I, Grade A)

Continuous Suturing vs. Interrupted

3RD STAGE: ACTIVE MANAGEMENT

Recommendations:Administration of prophylactic uterotonin

within one minute after the delivery of the baby and prior to the delivery of the placenta

Early cord clamping and cutting Clamping: never above the introitus Delaying the clamping?

3:80:60

Controlled cord traction to deliver the placenta

3RD STAGE:ACTIVE MANAGEMENT TO PREVENT PPH

Giving Uterotonins -> increased uterine contractions/retraction -> total detachment and expulsion of the placenta -> optimal occlusion of the myometrial vessels -> PPH prevented

The use of combination preparation (Oxytocin and Ergometrine) appears to be associated with a statistically significant reduction in the risk of PPH when compared to oxytocin alone where blood loss is less than 1000mL. (Level I, Grade B).

3RD STAGE:ACTIVE MANAGEMENT TO PREVENT PPH

Administration of oxytocin alone is as effective as the use of oxytocin plus ergometrine in the prevention of PPH, but is associated with a significantly lower rate of unpleasant maternal side effects (nausea, vomiting and hypertension). (Level II, Grade B)

3RD STAGE:ACTIVE MANAGEMENT TO PREVENT PPH

Recommended Dose:Ergometrine – 200-250 mcg IM OR 100-125

mcg IV bolus

Oxytocin – 10 ‘u’/500mL NSS (20 ‘u’/1000mL NSS) Continuous IV drip OR 5 ‘u’ IV bolus

3RD STAGE: DRUGS Recommendations

Oxytocin is effective as 1st line prophylactic uterotonic during the 3rd stage of labor in the prevention of PPH and is safe to use in all patients. (Level I)

Use of ergot alkaloid and Ergometrine-Oxytocin are valid alternatives in the absence of Oxytocin. Their use have to be weighed against maternal adverse effects. (Level I)

Use of ergot alkaloid and Ergometrine – Oxytocin combination have to be avoided in hypertensive patients. (Level I)

4TH STAGE Critical period

UterotonicsUterine Massage Ice pack

Breast feeding

REFERENCES: Williams Obstetrics, 22nd ed.

POGS Clinical Guidelines on Normal Labor and Delivery, April 2009

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