Management of labour & fetal assessment

King Khalid University HospitalDepartment of Obstetrics & Gynecology

Course 482

Management of labour & fetal assessment

Objectives:

Managements of the stages of labourPain relief in labourFetal assessment (antenatal & intra-partum)

Management of labour

Definition of labour:Progressive cervical effacement and dilatation resulting from regular uterine contractions that occur at least every 5 minutes and last 30-60 secondsBraxton Hicks: contractions Not associated with cervical changes

Lightening: Descent of the fetal head into the pelvisThere are 4 stages of labour

First stage of labourStart from onset of true labour pain----full dilatation of cervixIn primigravida------ 12 hour durationIn multigravida-----6 hours duration

Chiefly concerned with preparation of the birth canal as to facilitate expulsion of the fetus in the second stage

It has 2 phasesA latent phase up to 3 cm dilatation of cervix

• is variable: up to 8 hours in primi• 4 hours in multi

An active phase from 3 cm to full dilatation of cervixRate of dilatation 1 cm/hour in primigravida

• 1.5 cm/ hour in multigravida

Dilatation of the cervix

Dilatation usually measured by fingers but recorded in cm

Dilatation relates with dilatation of internal os

Effacement or taking up of cervix

Muscle fibers of cervix are pulled upward and merges with the fibers of the lower uterine segment

Cervix becomes thin during first stageIn primi----- effacement precedes dilatation of the cervixIn multi-----both occur simultaneously

Effacement is determined by the length of the cervical canal in the vaginaEffacement is expressed in terms of percentage

Effacement or taking up of cervix

First stage of labour

Maternal system-General condition remains

unaffected-Pulse rate increases by 10-15

bpm during contraction with the settle down to its previous rate in between contractions

-Systolic BP increase by 10 mm Hg during contraction

-Temperature remains unaffected

Fetal system-As so long as the membranes

are intact, usually there is no adverse effect on the fetus BUTHowever, during contraction there may be slowing of FHR by 10-20 bpm which soon returns to its normal as the intensity of contraction diminishes

Management of labour

Initial assessment:History: Onset, strength, frequency of contractionsLeakage of fluidVaginal bleedingFetal movementMedicationsLast oral intakeReview of past obstetric history, prenatal lab tests, gestational age, parity, size of previous infants, any antenatal complications

Management of the first stage of labour

--Informed consent on management of labour & delivery-Maternal position---lateral recumbent position

- Avoid supine hypotension-Partogram:

-Iv fluids & avoid oral intake-Maternal vital signs every 1-2 hours

-Input-output monitoring-Analgesia

- Fetal heart rate monitoring (CTG)-Uterine contractions monitoring

-Vaginal examination for cervical dilatation & poistion in active phase every 2 hours

--Amniotic membranes status & amniotic fluid colour

Monitoring progress of labour (Partogram)

Mechanics of labour

The Power: force generated by uterine contraction

Second Stage of labour

From full dilatation of cervix till delivery of the neonateThe mother has a desire to bear down with each contractionLast from 30 minutes to 3 hours in primigravida

5-30 minutes in multigravida

Mechanism of labour

Management of the second stage of labour

Molding (alteration of the relationship of the fetal cranial bones to each other as a result of compression forces by the bony pelvis)Caput (localized edematous swelling of the scalp caused by pressure of the cervix on the presenting portion of the fetal head)--- gives

false impression of fetal descent

Management of the second stage of labour

Crowning ( when the largest diameter of the fetal head is encircled by the vulvar ring)

-Vaginal examination every 30 minutes-Maternal position– any comfortable position for bearing

down-Bearing down---with each contraction

-Delivery of the fetal head---manual perineal support-Fetal airway clearance

-Umbilical cord clamping-Place the infant under warmer

Episiotomy

Incision in the perineum after crowning to aid delivery and avoid laceration of periniumTypes: Right mediolateral

Left mediolateral Central

PERINEAL LACERATION

4 TYPES:

-First degree: laceration involving the vaginal epithelium or perineal skin

-Second degree: laceration extending into the sub-epithelial tissues of the vagina or perineum with or without involving the perineal bodyThird degree: laceration involving anal sphincterFourth degree: laceration involving rectal mucosa

Third stage of labourThe interval between the delivery of the infant and complete delivery of the placenta & membranes

Duration is 5-30 minutes Signs of placental separation:

1 -Fresh blood show from vagina2 -The umbilical cord lengthens outside the vagina

3 -The fundus of the uterus rises up4 -The uterus becomes firm & globular

The placenta should be examined to ensure that it is completeThe blood loss should be estimated

Forth stage of labour

The hour immediately after the delivery

-Needs close observation of: blood pressure ,pulse rate, uterine blood loss

Watch for post partum hemorrhage

Pain relief in labour

Goal: effective pain relief to the mother that is safe for her & the fetus with minimal side effects on the progress & outcome of labour

Pain relief in labour

Non pharmacological method:

Back massageAcupunctureHypnosisBreathing exercises

Pain relief in labourPharmacological methods:

Narcotic analgesics– cross the placenta – cause fetal respiratory depression (Nitrous oxide, pethidine)Epidural analgesia: The most effectiveContra indicated if-coagulo-pathy, infection at needle site, severe hypo-volemiaSide effects: Hypotension, headache, impaired ability to push, prolonged second stage (15 Minutes)Pudendal block: for S2-S4

for the second stage of labour for instrumental delivery

Fetal assessment

Aim: Ensure fetal wellbeing ( Identify patients at risk of fetal asphyxia)

To prevent prenatal mortality & morbidity

Screening for high risk pregnancy

History *Age

*Social burden*Smoking

*Past medical conditions e.g D.M, HTN*Past Obstetric history

FETAL AND NEONATAL COMPLICATIONS OFANTEPARTUM ASPHYXIA

Stillbirth (Mortality)Metabolic acidosis at birth

Hypoxic renal damageNecrotizing enterocolitisIntracranial haemorrhageSeizuresCerebral palsy

CONDITIONS ASSOCIATED WITH INCREASEDPERINATAL MORBIDITY/MORTALITY

Small for gestational age fetusDecreased fetal movementPostdates pregnancy (>294 days)Pre-eclampsia/chronic hypertensionPre-pregnancy diabetesInsulin requiring gestational diabetesPreterm premature rupture of membranesChronic (stable) abruption

When to start fetal Assessment antenatally

**Risk assessed individually**For D.M. fetal assessment should start from 32

weeks onward if uncomplicated***If complicated D.M. start at 24 weeks onward

**For Post date pregnancy start at 40 weeks**For any patient with decrease fetal movement

start immediately **Fetal assessment is done once or twice weekly

Antenatal Fetal Assessment

Fetal movement countingNon stress test

Contraction stress test

Ultrasound fetal assessment

Umbilical Doppler Velocimetry

Fetal movement counting

Cardiff technique:

*Done in the morning, patient should:

calculate how long it takes to have 10 fetal movement

**10 movements should be appreciated in 12 hours

Fetal movement counting

Sadovsky technique:

-For one hour after meal the woman should lie down and concentrate on fetal movement

-4 movement should be felt in one hour-If not , she should count for another hour

-If after 2 hours four movements are not felt, she should have fetal monitoring

Non stress test

*Done using the cardiotocometry with the patient in left lateral position

**Record for 20 minutes

Non stress test

*The base line 120-160 beats/minute*Reactive:

At least two accelerations from base line of 15 bpm for at least 15 sec within 20 minutesNon reactive:

No acceleration after 20 minutes- proceed for another 20 minutes

Non stress test

If non reactive in 40 minutes---proceed for contraction stress test or biophysical profile

The positive predictive value of NST to predict fetal acidosis at birth is 44%

NST

NST

Contraction stress test

Fetal response to induced stress of uterine contraction and relative placental insufficiency

Should not be used in patients at risk of preterm labor or placenta previa

Should be proceeded by NST

Contraction stress test

Contraction is initiated by nipple stimulation or by oxytocin I.V.

The objective is 3 contractions in 10 minutes

If late deceleration occur-----positive CST

Interpretation of CTG

Normal Baseline FHR 110–160 bpm –Moderate bradycardia 100–109 bpm –Moderate tachycardia 161–180 bpm

–Abnormal bradycardia < 100 bpm –Abnormal tachycardia > 180 bpm

CTG

Acceleration

Deceleration

EARLY : Head compression

LATE : U-P Insufficiency

VARIABLE : Cord compression Primary CNS dysfunction

Early deceleration

Late deceleration

Variable Deceleration

Reduced Variability

TachycardiaHypoxia

ChorioamnionitisMaternal fever B-Mimetic drugs

Fetal anaemia,sepsis,ht failure,arrhythmias

Ultrasound fetal assessment

Assessment of growth

Biophysical profile (BPP)

Assessment of fetal growth by ultrasound

Biometry:

Biparietal diameter (BPD)Abdominal Circumference (AC)Femur Length (FL)Head Circumference (HC)Amniotic fluidPlacental localization

Assessment of fetal growth by ultrasound

BPD

AC

FL

Growth chart

Placental localization

Amniotic fluid

Fetal Biophysical profileBiophysical Variable

Normal (score=2) Abnormal (score= 0)

Fetal breathing movements

1 episode FBM of at least 30 s duration in 30 min

Absent FBM or no episode >30 s in 30 min

Fetal movements

3 discrete body/limb movements in 30 min

2 or fewer body/limb movements in 30 min

Fetal tone 1 episode of active extension with return to flexion of fetal limb(s) or trunk. Opening and closing of the hand considered normal tone

Either slow extension with return to partial flexion or movement of limb in full extension Absent fetal movement

Amniotic fluid volume

1 pocket of AF that measures at least 2 cm in 2 perpendicular planes

Either no AF pockets or a pocket<2 cm in 2 perpendicular planes

Test Score Result Interpretation Management

10 of 10

8 of 10 (normal fluid)

8 of 8 (NST not done)

Risk of fetal asphyxia extremely rare

Intervention for obstetric and maternal factors

8 of 10 (abnormal fluid) Probable chronic fetal compromise

Determine that there is functioning renal tissue and intact membranes. If so, delivery of the term fetus is indicated. In the preterm fetus less than 34 weeks, intensive surveillance may be

preferred to maximize fetal maturity.

6 of 10 (normal fluid) Equivocal test, possible

fetal asphyxia

Repeat test within 24 hr

6 of 10 (abnormal fluid) Probable fetal asphyxia Delivery of the term fetus. In the preterm fetus less than 34 weeks, intensive surveillance may be preferred to maximize fetal maturity

4 of 10 High probability of fetal asphyxia

Deliver for fetal indications

2 of 10 Fetal asphyxia almost certain

Deliver for fetal indications

0 of 10 Fetal asphyxia certain Deliver for fetal indications

Umbilical Doppler Velocimetry

Indication:

IUGRPETD.M.

Any high risk pregnancyUse a free loop of umbilical cord to measure blood flow in it

Umbilical cord

Umbilical Artery Doppler

Umbilical Artery Doppler

Umbilical cord doppler

Reverse flow in umbilical artery

Management of Abnormal Doppler

Depends on:

Fetal maturity

Gestational ageObstetric history

Management of Doppler results

Reverse flow or absent end diastolic flow--- Immediate delivery

High resistance index---- repeat in few days or delivery

Normal flow---- repeat in 2 week if indicated

Assessment for Chromosomal Abnormality

Ultrasound ----- nuchal translucency (N.T)Biochemical markers ---

1st trimester---PAPPA&βHCG

AmniocentesisChorionic villus sampling

Assessment for Chromosomal Abnormality

General Facts:•The general incidence of Down is 1:1000•The risk by maternal age: at the age of 35 -----------1:365 at the age of 40-----------1:109 at the age of 45-----------1:32•Risk of recurrence is 1% ( 0.75% higher than maternal age related risk•** In case of parental aneuploidy---- 30% risk of Trisomy in offspring

Methods available for screening for chromosomal abnormality

• Maternal age• Biochemical---1st trimester---PAPPA&β HCG,

• 2nd trimester---Triple & quadruple Test

• Ultrasound NT + Other markers

• Fetal DNA

Ultrasound screening for chromosomal abnormality

•Nuchal translucency(N.T)•Skin fold thickness behind the fetal cervical spine

• Timing: 11-13 +6days weeks of pregnancy

• 75-80% of trisomy 21

• 5-10% normal karyotype ( but could be associated with cardiac defects, diaphragmatic hernia, Exomphalos)

Nuchal translucency

Amniocentesis

Obtaining a sample of amniotic fluid surrounding the fetus during pregnancy ”.

Indications:

•Diagnostic (at 11- 20 weeks)•Therapeutic( at any time)

Indications of amniocentesis:•Genetic amniocentesis:

Chromosomal analysis (Down syndrome)Chromosomal analysis (Down syndrome)Spina bifida (Alpha fetoprotein)Spina bifida (Alpha fetoprotein)Inherited diseases (muscular dystrophy)Inherited diseases (muscular dystrophy)Bilirubin level in isoimmunizationBilirubin level in isoimmunizationFetal lung maturation (L/S ratio)Fetal lung maturation (L/S ratio)

Therapeutic amniocentesis:

•Reduce maternal stress in polyhydramnios

•Mainly in twin-twin transfusion or if abnormality associated

Amniocentesis

Chorionic villus sampling

Sampling is done to the cyto-trophoblastsSampling is done to the cyto-trophoblasts

done between 10-14 weeks of pregnancydone between 10-14 weeks of pregnancy

CVS

Recommended books

Essential of obstetrics & gynecology (p 91- 119)

Current diagnosis & treatment Obstetrics & gynecology (p 203-211 & p249-258 & p 441-460)