normal labour and abnormal labour

LABOUR

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CONTENTS

• Introduction• Fetal and maternal anatomy relevant to labour• The process of the labour• Physiology of the labour• Management of normal labour• Pain relief in labour• Abnormal labour• Labour in special circumstances• Induction of labour• Clinical risk management

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Introduction

• There is a complex interaction between the• “Powers of the uterus” –

• contractions

• “Passage” of the birth canal –• bony pelvis and the soft tissues of the pelvic floor and perineum)

• “Passenger” –• Fetus

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Fetal and maternal anatomy relevant to labour

• The pelvis• Pelvic brim/inlet• Pelvic mid cavity• Pelvic outlet• Pelvic floor• Perineum

• The fetal skull• Bones, sutures and frontenelles• Diameter of the skull

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Pelvic brim of inlet

• Is bounded

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Anteriorly

Posteriorly

Each sides Each sides

Symphysis pubis (joint separating the 2 pelvic bone)

• Upper margin of the pubic bone

• Ileopecteneal line• Ala of the sacrum

• Upper margin of the pubic bone

• Ileopecteneal line• Ala of the sacrum

Promontory of the sacrum

Pelvic brim of inlet

• Normal transverse diameter – 13.5 cm

• Normal AP diameter – 11cm

• Angle of the inlet normally 60º to the horizontal in the erect position

• Increased angle - delay the head entering (Afro Carribean)

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Bony pelvisJMJ 7Obstetrics by Ten Teachers 19th Edition

Pelvic BrimJMJ 8

Sagittal section of the pelvis demonstrating the AP diameter of the inlet and outlet

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Pelvic mid cavity

• Is bounded

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Anteriorly

Posteriorly


Middle of the pubic symphysis

• Pubic bone• Obturator fascia• Inner aspect of the

ischeal bone• Spines

Junction of the 2nd and 3rd sections of the sacrum

• Pubic bone• Obturator fascia• Inner aspect of the

ischeal bone• Spines

Pelvic mid cavity

• Cavity is almost round• Transverse and anterior diameter – 12 cm

• Ischeal spines are palpable vaginally • Are used as a landmarks to

• assess the descend of head on vaginal examination (station)• For providing an anesthetic block to the pudendal nerve

• Pudendal nerve passes behind and below the ischeal spine on each side

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Pelvic outlet

• Is bounded

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Anteriorly

Posteriorly


Lower margins of the pubic symphysis

• Descending ramus of the pubic bone

• Ischeal tuberosity• Sacrotuberous

ligament

• Descending ramus of the pubic bone

• Ischeal tuberosity• Sacrotuberous

ligament

Last piece of the sacrum

Pelvic outlet

• AP diameter – 13.5 cm• Transverse diameter – 11cm

• Transverse is the widest diameter at the inlet, but at the outlet it is the AP

• These measurements can be less in• Maternal stature• Previous pelvic fracture• Metabolic bone diseases (rickets)

• During 3rd trimester these become loosen• Pelvic ligaments at pubic symphysis• Sacroiliac joint

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Pelvic outlet


• GYNAECOID PELVIS• Most favourable for labour• Most common


• ANDROID - TYPE• Predisposes to deep transverse arrest


• ANTHROPOID SHAPE• Encourage an occipito-posterior position


• PLATYPELLOID PELVIS• Increase risk of obstructed labour


Pelvic floor

• Formed by• 2 lavetor ani muscles which,• with their fascia, • form a musculofascial gutter

during the 2nd stage of labour


Perineum

• Perineal body• Is a condensation of fibrous and muscular tissue • lying between the vagina and the anus

• It receives attachments from• Posterior end of the bulbocavenous muscles• Medial ends of the superficial and deep transverse perineal muscles• Anterior fibers of the external anal sphincter

• It is always involved in a 2nd degree perineal tear

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Superficial View

Obstetrics by Ten Teachers 19th Edition

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Deeper View


Fetal skull bones, sutures, frontenelles

• Fetal skull • Vault• Face• Base

• At the time of labour, • Sutures joining the bones of the vault are

• soft, unossifed membranes

• Sutures of the face and the skull base• Firmly united

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Fetal skull from superior and lateral view



• Vault is formed by• Parietal bones and parts of occipital• Frontal and temporal bones

• Between these bones there are 4 membranous sutures• Sagittal• Frontal• Coronal• Lambdoidal sutures

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• Anterior frontenelle (bregma)• Diamond shaped• At the junction of sagittal, frontal and coronal sutures

• Posterior frontenelle• Triangular shape• Lie at the junction of the sagittal suture & lamb

• The area of the fetal skull bounded by 2 parietal eminenses& the anterior and posterior frontenelles – “vertex”

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• Sutures allow these bones to move together and even to overlap• Paratial bones usually slides over the frontal and occipital bones• Bones are also compressible

• Together these characteristics of the fetal skull allow a process called “moulding”

• Which effectively reduces the diameter of the fetal skull and • encourages progress through the bony pelvis, • without harming the underlying brain• .

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Schematic representation ofmoulding of the fetal skull


Diameter of the skull

• Fetal head- ovoid in shape

• The attitude of the head • Refers to the degree of flexion and extension at the upper cervical

spine• Different longitudinal diameters are presented to the pelvis in

labour depending on the attitude of the fetal head

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PROCESS OF LABOUR

• The onset of labour• Stages of labour

• 1st stage• 2nd stage• 3rd stage

• Duration of labour• Mechanism of labour

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Onset of labour

• Can be defined as• Regular contractions bringing about progressive cervical change

• Diagnosis is made retrospectively

• Following does NOT define as onset of labour• Loss of ‘show’ ( blood-stained plug of mucus passed from the

cervix)• Spontaneous rupture of membranes (SPOM)

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Stages of labour – 1st stage

• Time from the diagnosis of labour, to full dilatation of the cervix (10 cm)

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1st stage

Latent phase Active phase

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Thick upper segment and the thinlower segment of the uterus at the end of the 1st stage of labour

Dotted lines indicate the positionassumed by the uterus during contractions


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Effacement • Is the process by which the cervix shortens in length as it becomes

included into the lower segment of the uterus• Begins during the weeks proceeding the onset of labour, but will

complete by the end of the latent phase.• Cervical os usually cannot begin to dilate until effacement is complete

• Effacement and dilatation should be thought of as • consecutive events in nulliparous women• Simultaneous events in multiparous women

1ST STAGE

LATENT PHASE

• Time between onset of labourand 3-4 cm dilatation

• Cervix become fully effaced

• Usually lasts between 3 – 8 hours

• Being shorter in multiparous women

ACTIVE PHASE

• Time between the end of latent phase and full dilatation (10cm)

• Usually lasting between 2-6 hours

• Shorter in multiparous women

• Cervical dilatation occurs at 1cm/hour –more in normal labour

• Abnormal – less than 0.5cm/hour

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2nd stage

• Time from full dilatation of the cervix to the delivery of the fetus or fetuses

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2nd stage

Passive phaseActive 2nd

stage

2nd STAGE

PASSIVE PHASE

• Time between full dilatation and the onset of involuntary expulsive contractions

• No maternal urge to push

• Fetal head is still relatively high in the pelvis

ACTIVE 2ND STAGE

• There is maternal urge to push

• Fetal head is low (often visible)

• Causing a reflex need to ‘bear down’

• Should last no longer than• 2hr- primiparous lady• 1hr- previous NVD

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Active 2nd stage

• If a woman never reaches a point of involuntary pushing, • the active 2nd stage is said to begin • when starts making voluntary active efforts • directed by her midwife.

• Active 2nd stage – lasting more than 3 hours• Associate with increase maternal and fetal morbidity

• Use of epidural anesthesia • May influence the length & management of 2nd stage of labour

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3rd STAGE

• Time from delivery of the fetus or fetuses until delivery of the placenta

• Placenta usually delivered within few minutes of the birth of the baby

• Lasting more than 30 minutes – Abnormal

• If women is under the ‘Physiological management’ – can last for 60 minutes

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Duration of labour

• Morale of most women starts to deteriorate after 6 hours in labour• After 12 hours the rates significantly accelerated

• Longer labours• Greater incidence of fetal hypoxia

• Early Artificial Rupture of Membranes (ARM)• Does shortens the length of labour,• Does not necessarily alter the outcome

• Prolonged labour• > 12 hours - nulliparous women• > 8 hours – multiparous women

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Mechanisms of labour

• Refers to the series of changes in

• position & attitude

• that the fetus undergoes

• during its passage through the birth canal

• Here describes on vertex presentation in a gynaecoid pelvis

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Mechanisms of labour

Engagement Descent Flexion

Internal rotationExtensionRestitution

External rotation

Delivery of shoulders and fetal body

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Engagement

• Head enters the pelvis – in transverse position

• Engagement is said to have occurred when, • Widest part of the presenting part has passed successfully through the

inlet

• It has occurred • In vast majority of nulliparous women prior to labour• Not so majority in multiparous women

• If more than 2/5th of fetal head is palpable abdominally – head not yet engaged

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Descent

• During 1st stage and 1st phase of the 2nd stage• Descent is 2ry to uterine contractions

• During Active phase of 2nd stage• Descent is helped by voluntary use of abdominal musculature &• Valsalva manoeuvre (‘Pushing’)

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Flexion

• Head may not always be completely flexed when it enters the pelvis

• When head enters then mid cavity flexion should occur

• This passive movements occurs, in part, • Due to surrounding structures • Important in minimizing the diameter of the fetal head

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Internal Rotation

• If head is well flexed, occiput will be the leading point• On reaching the sloping gutter of the levator ani muscles it

will be encourage to rotate anteriorly• So that the sagittal suture now lies in the AP diameter of the

pelvic outlet

• If babies head is in occipiti Posterior (OP) position-• Labour duration can be increased• May persist result in a ‘face to pubes’ delivery• Obstructed labour• Instrumental or Caesarean delivery

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Extension

• Following completion of the internal rotation• Occiput is underneath the symphysis pubis & • Bregma is near the lower boarder of the sacrum

• Soft tissue of perineum- still resistance, more prone to get damaged

• Well flexed head now extends,• & the occiput escapes from underneath the symphysis pubis & distends

the vulva • This is known as ‘Crowning’ of the head

• This will minimize the trauma to the soft tissues

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Restitution

• When head delivering – occiput is directly anterior

• As soon as it escapes from the vulva,

• the head aligns itself with the shoulders,

• which have enters the pelvis in the oblique position

• Slight rotation of the occiput through 1/8th of the circle is called ‘restitution’

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External Rotation

• In order to be delivered • Shoulders have to rotate into the direct AP plane

• When this occurs, the occiput rotates through a further 1/8th of a circle to the transverse position

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Delivery of the shoulders and fetal body• After restitution and external rotation occurred

• Shoulders will be in AP position

• Anterior shoulder • Is under the symphysis pubis• Delivers 1st

• Rest of the body will delivered easily

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LABOUR Physiology of labour

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Physiology of labour

• Myometrium

• Cervix

• Hormonal factors

• Mechanism responsible for initiating human parturition is still unknown

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MYOMETRIUM

• Myometrium cells • Contains filaments of actine and myosis• Which interact and bring about contraction,• In response to increase in intracellular calcium

• Prostaglandin and oxytocin• Increase intracellular free calcium ions

• Beta adrenergic compounds, CCB• Inhibits

• Separation of actin & myosin filaments brings about relaxation of myocytes

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MYOMETRIUM

• Development of upper thick segment• however, unlike in any other muscle cell of the body, • this actin– myosin interaction occurs along the full length of the

filaments • so that a degree of shortening occurs • with each successive interaction.

• This progressive shortening of the uterine smooth muscle cells is called retraction and

• occurs in the cells of the upper part of the uterus.

• Retraction – results in making upper segment (thick)

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MYOMETRIUM

• Development of lower thin segment• It is more stretched

• This results in cervix being taken up into the lower segment of the uterus

• Cervix effaces & then dilates,

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Thick upper segment and the thinlower segment of the uterus at the end of the 1st stage of labour

Dotted lines indicate the positionassumed by the uterus during contractions


Myometrium

• Myocytes of the uterus contracts together

• Individual myometial cells are laid down in a mesh of collagen

• Cell-to-cell communication by gap junctions• These gap junctions are absent for most of the pregnancy ,

but appears at term• Prostaglandins stimulate the formation of gap junction• Beta- adrenergic - opposite

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Myometrium

• Uterine contractions are involuntary in nature

• Minimal extrauterine neuronal control

• Majority of labour –• occurs at intervals of 2-4 minutes

• Intensity or amplitude of the intrauterine pressure generated with each contraction averages between 30 to 60 mmHg

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Cervix• Contains muscles and fibroblasts,

• Separated by ‘ground substance’ made up of extracellular matrix molecule

• Under the influence of prostaglandin and other humoral mediators• There is an increase in proteotyric activity• Reduction in collagen and elastin

• Interleukins bring about a pro-inflammatory change – with significant invasion by neutrophils

• Dermatan sulphate is replaced by the more hydrophilic hyaluronic acid

• Which results in increase in water content in cervix

• This causes cervical softening or ripening,

• So that contractions, when they begin, can bring about the process of effacement and dilatation

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Hormonal factors• Progesterone

• Maintains uterine quiescence by,• Suppressing prostaglandin production• Inhibiting communication between myometrial cells and

preventing oxytocin release

• Oestrogen• Opposes the action of progesterone

• Prior to labour, • there is a reduction in progesterone receptors and • an increase in the concentration of oestrogen relative

to the progesterone

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Hormonal factors• By chorion and decidua

• Increased prostaglandin synthesis• Leading to increase in calcium influx into myometrial

cells

• Corticotrophin-releasing hormone (CRH)• Produced by placenta• Increase contractions towards term• Potentiates the action of prostaglandin & oxytocin on

myometrial contractility

• Fetal pituitary oxytocin• Fetal adrenals cortisol

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Stimulates the conversionof progesterone to oestrogen

LABOURMANAGEMENT OF NORMAL LABOUR

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History

• Details of previous births & the size of previous babies• Frequency, duration & perception of strength of the contractions

and when they began

• Whether the membranes have ruptures• Colour and amount of amniotic fluid

• Presence of abnormal vaginal discharge or bleeding• Recent activity of the fetus• Any medical issues• Special requirements (psychological needs)

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General Examination

• Body mass index

• Temperature

• Pulse

• Blood pressure

• Urine tests for• Protein / blood / ketones/ glucose

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Abdominal Examination

• Inspection for scars• Lie of the fetus• Presenting part

• Cephelic or breech

• If cephalic, degree of engagement• If 5/5 – do USS- to figure out the reason for high head

• OP position• Deflexed head• Placenta previa• Fibroids

• Assessment of contractions – by palpation• Can comment only on frequency and duration of contractions• Not the strength

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Vaginal Examination

• Examine cervix for• Dilatation• Effacement• Application of the presenting part

• Dilatation – comment by cm• If cannot feel for the cervix- fully dilated

• Length of the cervix• At 36 weeks – 3cm

• At about 4cm of dilatation, the cervix should be fully effaced

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Vaginal Examination

• Normal labour- presenting part is vertex

• Occiput is identified by feeling for triangular posterior frontenelle

• Normally occiput will be • Transvers (OT position)• Anterior (OA position)

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Vaginal Examination

• Conditions of the membranes should be noted• Copious amount of clear fluid –

• good prognosis• Heavily blood stained or meconium stained fluid –

• warning sign for fetal compromise

• Women in labour should have their,• Pulse measured – hourly• Temp, & BP – 4 hourly• Frequency of contractions – 30 minutes• Vaginal examination – 4 hourly

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FETAL ASSESSMENT IN LABOUR

• CTG – Cardio-toco-graphy• PARTOGRAM

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Fetal assessment in labour

With each contraction

Low placental blood flow

Low Oxygen to fetus

Switch to anaerobic

metabolism

More lactic acid and H+

Metabolic acidosis

Neuronal damage Intrapartum fetal death

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Passage of meconium

• Thin, very dark green or brown colour• Healthy fetus• Results of maturation of gastrointestinal physiology

• Thicker and much brighter green in colour• Intrauterine hypoxia or acidosis

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Fetal assessment in labour takes four forms• Observation of the colour of the liquor

• Intermittent auscultation of fetal heart using Pinardstethoscope or a hand held Doppler US

• Continuous external fetal monitoring (EFM)-by CTG

• Fetal scalp blood sampling (FBS)

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Fetal assessment in labour

• Women who bring labour with intermittent auscultation

• may be advised to change to continuous EFM

• if any of the following events occur during their labour• Significant meconium staining to liquor• Abnormal fetal heart rate detected by intermittent auscultation• Maternal pyrexia• Fresh vaginal bleeding• Augmentation of contractions with oxytoxin• At the request of the woman

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CTG


CTG

• Quality is poor• Due to fetal position • Maternal obesity

• Normal parameters• Normal fetal heart rate pattern

• Baseline rate between 110-160 bpm• Baseline variability between 5 and 25 bpm• Absence of decelerations

• During 2nd stage of labour• Absence of accelerations• Presence of early decelerations tends to be normal

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CTG

• Each feature of CTG (baseline rate, variability, decelerations and accelerations), should be assessed each time

• Should describe as ‘reassuring’ , ‘Non-reassuring’ or ‘abnormal’ (NICE guidelines)

• If all 4 features reassuring –• Normal CTG

• If one is non-reassuring-• Suspicious CTG

• If 2 or more non-reassuring or any abnormal –• Pathological CTG

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Partogram

• Instance visual assessment of the rate of cervical dilatation

• Progression of the labour

• Frequency and strength of contractions

• Descent of the head in 5th palpable

• Amount and colour of the amniotic fluid draining

• Basic observation of maternal wellbeing • BP/ Pulse rate/ Temprature

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Management during 1st stage

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Key management principles of 1st stage of labour• 1st stage – timed from the Δ of labour to full dilatation of cervix

• Provision of continuity care and emotional support

• Observation of progression of labour

• Monitor fetal well being

• Adequate and appropriate pain relief

• Adequate hydration to prevent ketosis

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management of 1st stage of labour

• Woman in latent phase –• encourage to mobilize• Encourage and reassure them• Avoid interventions unless there is an identified risk factors• Simple analgesics preferred over NO and epidurals• No need to restrict eating and drinking (light food and clear fluid-

tolerable)• Vaginal examination – in every 4 hours

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• Woman in active phase – (Cervical d-4cm)• Lower limit of normal progression – 1cm dilatation in every 2 hours• Descend of the fetal part

• Full dilatation may be reached, but id descent is inadequate, vaginal delivery will not occur

• During 1st stage• Membranes may be intact, ruptured spontaneously or ruptured artificially

• Maintain a partogram- maternal and fetal observations

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• Mobility during labour is encourage (standing upright encourage the progress

• Encourage drinking water• If the woman is dehydrated- start IV fluids• To prevent ketosis, which can impair uterine contractions

• Light diet is accepted -• if no indication for GA• If they have not had pethadine or diamorphine

• Shaving and enemas are unnecessary• Antacids need only to women

• with risk factor for complications• Those who have opioid analgesia

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Active management of labour

• Collections of interventions

• Which are routinely recommended to

• Nulliparous women

• To maximize the chances of a normal birth

• This includes• 2 hourly vaginal examination• Early artificial rupture of membranes• Use of oxytocin augmentation if progress fell more than 2 hours

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Management during 2nd stage

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• 1st sign of the 2nd stage-• urge to push experienced by mother

• Full dilatation of cervix-• Should be confirmed by a vaginal examination, if the head is

not visible

• The women will get an expulsive reflex with each contraction, & will generally take• Deep breath, hold it and strain down (Valsalva manoeuvre

• Woman should be discourage lying supine or semi supine• Lying in the left lateral position & squatting are

particularly effective options

• Use of regional analgesia may interfere with normal urge to push

• Pushing is usually delayed for at least an hour if an epidural is in situ (‘passive phase’),

• However baby should be delivered within 4 hours after full dilatation

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Descent and delivery of the head

1st there is a slight general bulge as the woman strains

When head stretches the perineum, anus will begin to open

Soon after this babies head will be seen at the vulva

Between the contractions, elastic tone of the perineal muscles will push the head back into pelvic cavity

Perineal body and vulva stretches more, until fetal head is low enough to pass forward under the suprapubic arch

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Descent and delivery of the head… cont

When head no longer recedes between contractions (crowning) – indicated head had passed through pelvic cavity

When crowning has occur, tell woman to take rapid, shallow breaths (‘panting’)

An episiotomy cut is performed (from vaginal fourchette in a Medio lateral direction – to right)

Episiotomy is performed during –1. instrumental birth2. suspected fetal compromise

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Delivery of the shoulders and the rest of the body

Once fetal head is born, check whether the cord is wound tightly around the neck

If yes, cord need to clamp before delivering the rest of the body

With next contraction external rotation of the head and shoulders can be delivered

To aid delivery of the shoulders, head should be pulled gently downwards and forwards until A shoulder appears beneath the pubis

Head then lifted gradually until the P shoulder appears over the perineumbaby then swept upwards to deliver the body and legs

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Immediate care of the neonate

• After born, infant lies between mother’s legs • Baby will usually take 1st breath within seconds

• No need for immediate clamping of the cord• Nearly 80ml of blood will transferred from placenta to the baby, before

cord pulsation cease• Reduces the chances of neonatal anemia and iron deficiency

• Oropharyngeal aspiration is only done if necessary • After clamping & cutting cord – calculate APGAR score –

• 1 minute and • 5 minutes

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Immediate care of the neonate

• Immediate skin to skin contact between mother & baby• Help bonding• Promote further release of oxytocin

• Baby should be dry and cover with warm blanket• Initiation of breastfeeding – 1st ½ hour of life

• Newborn measurements – temperature, head circumference, birth weight

• 1st dose of vitamin K should be given

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Management during 3rd stage

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• Normally take 5 to 10 minutes

• Separation of placenta occurs because• Reduction of volume of uterus

• Due to uterine contractions and retraction

• Signs of separation are• Lengthening of the cord protruding from vulva• A small gush of blood from the placental bed, which normally stops

quickly due to retraction of the myometrial fibers• Rising of the uterine fundus to above the umbilicus• Fundus becomes hard & globular compared to board

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Mx of 3rd stage

Active Mx

IM 10 IU of oxytoxin -given as the A soulder of

the baby is deliverd / immediately after delivery

Early clamping and cutting of umbilical

cord

Controlled cord traction

Physiological Mx

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Active Management

• Recommended to all women – to reduce risk of PPH

• When signs of placental separation are recognized • Control cord traction is used

• When contractions are felt• Left hand should be moved suprapubically• & the fundus elevated with the palm facinf toward the mother• Right hand should grasp the cord• Use twisting motion

• Uterine inversion – rare complication

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Active Management

• 2% - placenta will not expelled

• If no bleeding occurs• Further attempt at controlled cord traction should be made after 10

minutes

• If that fails manual removal under GA or regional anesthesia

• Direct injection of oxytocin into the umbilical vein – may bring about delivery of the placenta

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Physiological Management

• Where the placenta is delivered by the maternal effort

• No uterine drugs are given to assist

• Associated with heavy bleeding

• Can wait up to 60 minutes

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• After completion of 3rd stage• Inspect placenta for missing cotyledons or succenturiate

lobe• If anything suspected -> manual removal (US guided)

• Inspect vulva for an tears extending into perineal muscles

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Key features of normal labour are

• Spontaneous onset• Single cephalic presentation• 37- 42 weeks gestation• No artificial interventions• unassisted spontaneous vaginal delivery• Dilatation of at least 1cm every 2 hrs in the active phase of 1st stage• An active 2nd stage of no more than 2hr primiparous woman

no more than 60 minutes in multiparous woman• 3rd stage lasting no more than 30 minutes with active management

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LABOUR – 02ABNORMAL LABOUR

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Abnormal Labour

Poor progression of

labour

1st stage

Dysfunctional uterine activity

Cepahlopelvicdisproportion malpresentation Anomalies of

birth canal

2nd stage

Patterns of normal progress

of labour

Fetal compromise in

labour

Recognition Management

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Poor progress of 1st stage of labour

• Defined as• Cervical dilatation of less than 2cm in 4 hours• Associate with failure of descent &• Rotation of the fetal head

• Progress dependent on 3 variabilities• Power

• The efficiency of the uterus• Passenger

• Fetus (Size, presentation, position)• Passage

• Uterus, cervix, bony pelvis

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Dysfunction of the uterine cavity

• Most common cause

• Common in primigravida & older women(weak contractions)

• Assessment done by• Clinical examination• External uterine tocography• Intrauterine pressure catheter (more accurate)

• Frequency of 4-5 contractions per 10 minutes- ideal

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• When poor labour suspected• Repeat vaginal examination 2 hrly

• If confirmed• ARM

• If still poor progress till 2 hours• Oxytocin infusion- slow rate• Increase carefully in 30 minutes

• Continuous EMF• Multiparous women- less likely to experience poor progress (excepts

malposition or malpresentation)

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• Excessive uterine contractions in a truly obstructed labour• Results in uterine rupture in multiparous women

• Augmentation with oxytocin is contraindicated

• if there are concerns regarding the condition of the fetus

• If progress fails to occur despite 4-6 hours of augmentation with oxytocin,

• a Caesarean section will usually be recommended

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Cephalopelvic disproportion (CPD)

• Anatomical disproportion between the fetal head and maternal pelvis• Due to

• Large head• Small pelvis• Combination of the 2

• Women with short stature (<1.60m), with a large baby in their 1st pregnancy –high risk

• Obstructive hydrocephalus – macrocephaly• Fetal thyroid & neck tumors – extension of neck• OP position – deflexion of the fetal head , presents a larger skull diameter to

the maternal pelvis

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Cephalopelvic disproportion (CPD)

• Cephalopelvic disproportion is suspected in labour• Progress is slow or actually arrests despite efficient uterine

contractions• The fetal head is not engaged• Vaginal examination shows sever maulding & caput formation• Head is poorly applied to the cervix

• Oxytocin can be given carefully to a primigravida with mild to moderate CPD

• Oxytosin must never be used in a multiparous women where CPD is suspected

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Malpresentations

• Vital good progress in labouris the tight application of the fetal presenting part on to the cervix

• Face presentation• May apply themselves poorly to

the cervix• Vaginal birth is still possible


Malpresentations


Malpresentation

• Brow presentation• Mento-verticle diameter • Too large to fit through the bony pelvis, unless flexion occurs or • hyperextension to a face presentation

• Shoulder presentation• Cannot deliver vaginally

• Malpresentations are common in women with• High parity• Risk of uterine rupture

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Abnormalities of the birth canal

• Abnormalities of the uterus and cervix

• Unsuspeccted fibroids in the lower uterine segment –prevent descend

• Delay can caused by cervical dystocia• non-compliant cervix which effaces but fails to dilate because of

severe scarring, usually as a result of a previous cone biopsy.

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Poor progress in the 2nd stage of labour

• Birth is expected to take place within 3 hrs of the start of the active 2nd stage

• Delay diagnosed if delivery is not immitent after• 2 hr of pushing – nulliparous labour• 1 hour of pushing – multiparous labour

• Causes for 2nd stage delay• Abnormalities of power• Passenger• passage

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• 2ry uterine inertia –• common cause of 2nd stage delay• May be exacerbated by epidural analgesia

• Maternal dehydration causing ketosis• Weak uterine contractions• Tx-rehydration & IV oxytocin –if primi

• Persistent OP position – fetal head• Either head has to undergo long rotation to OA

position• Delivered in the OP position (face to pubes)

• When 2nd stage has been diagnosed,• Never start oxytocin

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• Narrow – mid pelvis (android pelvis)• Prevents internal rotation of fetal head

• This may result in the arrest of the descent of the fetal head

• at the level of the ischial spines • in the transverse position

• “DEEP TRANSVERSE ARREST”

• Instrumental birth should be considered for prolonged 2nd stage

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Risk factors for poor prognosis in labour• Small woman

• Big baby

• Dysfunctional uterine activity

• Malpresentation

• Malposition

• Early membrane rupture

• Soft-tissue/pelvic malformation

JMJ 123

Patterns of abnormal progress in labour• Partogram


• Prolonged latent phase• More common in primiparous woman

• Primary dysfunctional labour• Poor progress in the active phase of labour (<2cm

cervical dilatation/4 hourly)• Common in primi women

• 2ry arrest • When progress in the active phase of 1st stage is

initially good but then slows, • stops altogether• Typically after 7cm dilatation

JMJ 125

Poor progress in labour

• Different patterns +• Insufficient uterine cavity – most common cause• Fetal malposition, malpresentation, and true CPD are other causes

• May occur in isolation or in combination with inefficient uterine contractions• ARM is a simple intervension which may shortens labour, but does not influence the overall

outcome• Use of oxytocin – relatively safe in nulliparous women• Use of oxytocin augmentation – less safe because of greater risk of uterine

hyperstimulation, fetal compromise & uterine rupture in the face of obstruction• Oxytocin does not have a significant impact on the mode of delivery, but does shorten the

length of labour

JMJ 126

Fetal compromise in labour

• Reduction in placental blood flow associated with contractions • Lead to fetal hypoxia• Eventually acidosis

• Fresh meconium staining to the amniotic fluid• Abnormal CTG

• ‘Presumed fetal compromise’ more accurate than ‘fetal distress’

JMJ 127

Risk factors for fetal compromise in labour• Placental insufficiency – fetal growth restriction and pre-eclampsia

• Prematurity

• Postmaturity

• Multiple pregnancy

• Prolonged labour

• Augmentation with oxytocin

• Uterine hyperstimulation

• Precipitated labour

• Intrapartum abruption

• Cord prolapse

• Uterine rupture / dehiscence

• Maternal diabetes

• Cholestasis of pregnancy

• Maternal pyrexia

• Chorioamnionitis

• Oligohydroamnios JMJ 128

Recognition of fetal compromise

• Meconium staining• Thick or tenacious• Dark green• Bright green• Black

• Thin & light meconium – is more likely to represent fetal gut maturity

• CTG changes• Fetal tachycardia• Fetal bradycardia• Fetal heart rate deceleration

JMJ 129

CTG signs suggestive of fetal compromise• Fetal tachycardia (>160 bpm, or a steady rise over the

course of labour)

• Loss of baseline variability (<5bpm)

• Recurrent late decelerations

• Persistent variable decelerations

• Fetal tachycardia (<100 bpm for more than 3 minutes)

JMJ 136

Management of possible fetal compramise• Number of resuscitative manoeuvres

• Should be considered when a CTG is classified as ‘suspicious’

• If a CTG becomes pathological • Do immediate vaginal examination to exclude malpresentation and cord

prolapse

• If cervix is fully dilated, • Deliver baby vaginally

• If cervix is not dilated• Instrumental delivery• Caesarean section

JMJ 137

Resuscitating the fetus in labour

• Maternal dehydration and ketosis• Can corrected with IV fluids

• Maternal hypotension • 2ry to an epidural • Can be reversed by a fluid bolus• Although a vasoconstrictor such as ephedrine is occasionally necessary

• Uterine hyper stimulation• From excess oxytocin can be treated by • turning off the infusion temporarily and • using tocolytic drugs (terbutaline)

• Venocaval compression and reduced uterine blood flow • Can be eased by turning the woman into left lateral position

JMJ 138

LABOUR O3LABOUR IN SPECIAL CIRCUMSTANCES

JMJ 139

Labour

Woman with a uterine scar Malpresentation

Breech presentation

Face presentation

Brow presentation

Shoulder presentation

Multiple gestation

JMJ 140

Women with a uterine scar

• 20% deliveries are Caesarean sections

• Out of that 99% - lower segment of the uterus• Blood loss is less• Healing is better• Low risk of uterine rupture

• Upper segment C- section “ classical”

JMJ 141

Signs of uterine rupture

• Severe lower abdominal pain

• Vaginal bleeding

• Hematuria

• Cessation of contractions

• Maternal tachycardia

• Fetal compramise

JMJ 142

• Uterine rupture likely to occur• Late in 1st stage of labour• With induction or accelerated labour• In association with a large baby

• Labour after previous Caesarean section• Vaginal birth after Caesarean section

JMJ 143

VBAC after delivery

75%

C section25%

PERCENTAGE OF PERFORMING VBAC

• Contraindications for VBAC• 2 or more previous Caesarean section scars• Need for induction of labour (IOL)• Previous labour progress and outcome suggestive of CPD

• Previous classical Caesarean section• Absolute contraindication

• Previous myomectomy• Minimal danger for rupture of membranes

JMJ 144

JMJ 145

Breech presentation

• Increased risk of cord prolapse• With footing breech presentation• With flexed breech

• Increased risk of CTG abnormalities• Cord compression

• Mechanical difficulties with delivery of the shoulder &/or after coming head• Damage to visceral organs• Traction of brachial plexus• Prolonged compression of umbilical cord & asphyxia

JMJ 146

Face presentation

• 1.500 labours• 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.

• Because facial bones do not mould

• Diagnosed by palpating nose, mouth and eyes on vaginal examination

• Forcep delivery is permitted for low mento-anterior face presentations

JMJ 147

Face presentation

• Excellent prognosis if• If chin remains meto anterior• Possible vaginal delivery• Head being delivered by flexion

• Poor prognosis if• Chin is posterior (mento-posterior position)• Extension over the perineum cannot occur• C-section is performed• Oxytocin should not be given

JMJ 148

Brow presentation

• Lesser extreme extension of the fetal neck that that with a face presentation

• can be considered a midway position between vertex and face

• 1:2000• Brow presentation –

• As a result of exaggerated extension associated with OP position

• Presenting diameter (mento-vertical) – 13.5cm• Incompatible with a vaginal delivery

JMJ 149

Brow presentation

• Diagnosed by palpating • anterior frontenelle• Supra-orbit ridges• Nose

• If this presentation persist• Delivery by Caesarian section

JMJ 150

Shoulder presentation

• 1:300

• Due to transverse oblique lie of the fetus

• Cause of this abnormal presentation include placenta Previa

• Delivery by Caesarean section

• Delay making the diagnosis have risk of• Cord prolapse• Uterine rupture

JMJ 151

Multiple Gestation

• 1:80

• Indications for elective Caesarian section in twin pregnancy• Malpresentation of the 1st twin• Second twin larger than the 1st

• Evidence of FGR in one or both twins• Monoamniotic twins• Placenta previa• Maternal request

JMJ 152

Key points• Most labours are uncomplicated and the outcomes are good.• Labour can be a hazardous journey for the baby.• Abnormalities of the uterine contractions (the ‘powers’), the fetus

(the ‘passenger’) and the pelvis and lower genital tract (the ‘passages’) can cause abnormal labour.

• The term ‘fetal distress’ is unhelpful and often misleading. If there are concerns regarding fetal well-being in labour, the term ‘presumed fetal compromise’ should be used instead.

• Augmentation of labour with oxytocin will often correct poor uterine contractions and may help to resolve fetal malposition.• Augmentation of labour with oxytocin can be dangerous in multiparous women, in those with a uterine scar, and in cases of malpresentation

JMJ 154

INDUCTION OF LABOUR

JMJ 155

Common indications for induction of labour• Prolonged pregnancy• Fetal growth restriction• Pre-eclampsia and other maternal hypertensive disorders• Deteriorating maternal illnesses• Prelabour rupture of membranes• Unexplained antepartum haemorrhage• Diabetes mellitus• Twin pregnancy continuing beyond 38 weeks• Intrahepatic cholestasis of pregnancy• Maternal iso-immunization against red cell antigens• ‘Social’ reasons

JMJ 156

induction of labour

• Recommended IOL between 41 & 42weeks

• Longer the time delay between delivery of the baby and membrane rupture• Greater risk of ascending infection (chorioamnionitis)

• Before 34 weeks• Maternal infection, fetal compromise, growth restriction

• Between 34-37

JMJ 157

Methods

• Artificial rupture of membranes

• Synthetic syntocin (Syntocinon)

• Prostaglandin PGE2• Inseted vaginally• Posterior fornix – tablet or gel• 2 doses given – 6hrs apart

• Controlled release pessery – 24hrs• Prostaglandin recommends even if the cervix is favourable

JMJ 158

Methods

• Oxytosin given IV as a dilute solution

• Mifepristone (anti-progesterone)

• Misoprostol (prostaglandin)

• Membrane sweeping - ARM

JMJ 159

Bishop score

JMJ 160

High score - favourable cervixLow score – unfavourable cervix


Risk of induction of labour

• Greater pain in labour

• Uterine hyperstimulation

• Cord prolapse

• Greater risk of uterine rupture during VBAC

• Failure

• Increased need for Caesarean or instrumental delivery

• Fetal compromise

JMJ 161

Induction of labour and clinical risk management

• • Every induction of labour should have a valid indication.

• • The most common indication for induction of labour is prolonged pregnancy.

• • A high Bishop score predicts an easier induction of labour.

• • Clinical risk management aims to improve standards of intrapartum care and to reduce the number and severity of poor obstetric outcomes.

JMJ 163

THANK YOU!

JMJ 164

normal labour and abnormal labour

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