preterm labor.ppt

8/10/2019 preterm labor.ppt

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PRETERM LABORDR. SHABNAM NAZMBBS, MCPS, FCPS

ASSISTANT PROFESSOR

OBGYNSHAHEED MOHTARMA

BENAZIR BHUTTO

MEDICAL UNIVERSITY LARKANA


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OBJECTIVES

Define PTL and describe their significance

List risk factors associated with PTL

Outline initial evaluation of PTL

Describe management of PTL Discuss neonatal GBS prevention

strategies.


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Preterm labor

Labor before 37 completed weeks of

gestation


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TERMINOLOGY

Preterm birth: 24-36+6wks

Indicated preterm birth

Spontaneous preterm birth

(3contractions/10 min +cervical changes) Preterm premature rupture of membrane

Premature ROM(1hr or more before onset of labour)

PPROM(premature ROM before 37 wks)


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Classification of preterm birth

Mildly preterm birth - 32 - 36 weeks

Very preterm birth - 28 - 31 weeks

Extremely preterm birth - 24 - 27 weeks


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Incidence

Accounts for 85% of all perinatal mortality

and morbidity.

8-12% of all deliveries are preterm.

71.2% 34-36 weeks 13% 32-33 weeks

10% 28-31 weeks

6%


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Survival in Premature Infants

survival chance is directly proportional to the maturity

26 wks 80%

27 wks 90%

28-31 wks 90 to 95%

32-33 wks 95%

34-36 wks approaches term

survival rates


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Complications of Prematurity RDS IVH

Feeding difficulties/NEC

Apnea

PDA

Infection

Jaundice

Hypothermia

Neurobehavioral

ROP

Anemia


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Pathogenesis

Premature activation of maternal or fetal

HPA axis

Decidual hemorrhage

Inflammation/infection

Pathological uterine distention


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Mechanisms For Preterm Labor


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Penyebab Persalinan Preterm


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Can preterm labor bepredicted?


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Prediction1. Assessment of risk factors

2. Vaginal examination to assess the cervical status

3. Ultrasound visualization of cervical length and dilatation

4. Detection of fetal fibronectin in cervicovaginal secretions


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Risk factors for preterm birth

Relative riskRisk factors


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2-Vaginal examination

Digital examination is the traditional

method used to detect cervicalmaturation, but quantifying these

changes is often difficult.


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3-Vaginal U/S

Vaginal Ultrasonography allows a

more objective approach to

examination of the cervix.


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Sonographic Cervical Length

80-100% of women who

deliver early have cervix


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Fetal Fibronectin

Fetal Fibronectin (fFN)- it is a glue like protein bindingchoriodecidual membrane

Present in vaginal secretions between 23-34weeksand signifies onset of labor

Bedside test can be done if negative it rules out

preterm labor in next two weeks P/V examination gives false positive result for 24 hours

Between 24-32 weeks

fFN

25ng/ml + cervical length of 25 mmshows significant risk


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Prevention ofpreterm labor


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Prevention of PTB

Reduce/eliminate risk factors, if possible

Not proven to be effective: bedrest, home

uterine monitoring, prophylactic tocolytics,

prophylactic antibiotics, abstinence. Supplemental progesterone

Women with previous spontaneous preterm delivery

at less than 34 weeks gestation

Weekly 17OHprogesterone IM or daily vaginal

progesterone suppositories

Start at 16-20 wks gestation, continue through 36

weeks


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Treatment Of Vaginosis

Treatment of asymptomatic abnormal vaginal flora

and bacterial vaginosis with vaginal

clindamycin or oral metronidazole earlyin the 2nd trimestersignificantly reduces the rate

of late miscarriage and spontaneous preterm

birth.


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DIAGNOSIS

OF

PRETERM LABOR


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Diagnosis

Three

criteria to document PTL(20-37wks)

1-Regular uterine contractions occur at 4/20 min. or8/60 min. Plus: progressive change in the cervix.

2- Cervical dilatation > 1 cm

3- Effacement >80%.


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Four Questions:

Is the patient in labor?

Are the membranes ruptured?

Is the fetus preterm?

What risk factors are present?


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PATIENT HISTORY

Detailed history of labor.

History of fluid leakage.

Dating of pregnancy.

Review history for risk factors. History of other medical problems.

Assessment of social history and home

support.


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PHYSICAL EXAMINATION

Maternal vitals: signs of infection.

General physical exam.

Fetal heart rate pattern.

Fetal size and presentation. No digitals cervical exam if membrane

rupture suspected.


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STERILE SPECULUM

EXAMINATION

Assess for membrane rupture:

Pooling of fluid in vagina.

Nitrazine and fern test.

Assess cervix visually.

Obtain cervical cultures.

Obtain wet prep for vaginitis, if no ROM.

Obtain GBS culture of outer vagina and

rectum.


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ADDITIONAL TESTS

CBC, Urinalysis. Evaluate for maternal infection.

Amniocentesis. Assess fetal lung matunity.

Ultrasound Assess amniotic fluid index. Determine (+/ - 3 weeks) gestational

age.

Transvaginal scan for cervical length. Normal cervical length = 35 mm

Significant cervical length = 25 mm

Funnelling of membrane

Cervioovaginal swab for fetal

fibronection.


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MANAGEMENT

OF

PRETERM LABOR


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MANAGEMENT OF PRETERMLABOUR

Prophylactic management

Management in labour Management after

delivery

Prophylactic


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Prophylactic

Management

Good antenatal care.

All diseases should be controlled well.

In multiple pregnancy rest andsedatives very

important

In incompetent Cx. Circlage stitches.

Diabetic treatment.

Tocolytic therapy


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Management of Acute

Preterm Labour

Sedation and hydaration

Bed rest and hydration are commonlyrecommended, but without provenefficacy. (risk of DVT in bed rest).

Probable role of hydration decreasesecretion of ADH + oxytocin from postpitutary

Steroids

Antibiotics

Tocolysis


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Role of Steroids

Single course of antenatal steroids b/w 24 and34 wks of gestation with intact membranes and24-32 wks in PPROM reduces the risk ofRDS,IVH, NEC, Sepsis and neonatal mortalityby 50%.

Dose

Betamethasone 12mg i/m B.D for 24 hrs.

Dexamethasone 6 mg i/m every 6 hours for 24hours.


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MOA of steroids.

1. Stimulates type II pneumocyctes to produce surfactant.2. Structural development of lungs3. Accelerated maturation of fetal intestines (Prevent NEC).

effect on myocardium (Prevent IVH)

Repeated Dose increased sepsis in PPROM.Restricted fetal body and brain growth .Adrenal Suppresssion.

Increase risk of NND


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TRH, Vitamine K , Phenobarbitone

The use of thyrotropin-releasing hormone (TRH), vitamin

K and phenobarbitone to improve neonatal outcome has

been studied in randomized trials, but has not been

shown to be beneficial.


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Role of Antibiotics

(Oracle Trail)

Administration of antibiotics to the mother

do not delay delivery.

Only positive health benefit is a reduction

in maternal infection rates.


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Is Tocolysis Better Than No Tocolysis For

Preterm Labor?

It is reasonable not to use tocolytic drugs, as there is no

clear evidence that they improve outcome. However,tocolysis should be considered if the few days gained

would be put to good use, such as

completing a course of corticosteroids,

or in utero transfer

TOCOLYSIS


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Tocolytics

There is no reliable data to suggest tocolytics agent is

able to delay the delivery for longer than 48 hours.

No single agent has a clear therapatic advantage.

Maintenance tocolysis beyond 48 hours is not

recommended, it has not been shown to delay deliveryand is associated with Significant adverse effect.


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Tocolytics

Recent meta analysis suggest that

maintenance tocolytic with nifedipine

may be beneficial.

Concurrent use of tocolytics has no more

effective than single agent alone and has

more S.E so not recommended.

Most authorities do not recommend use oftocolytics at or after 34 weeks' .

There is no consensus on a lower

gestational age limit for the use of tocolytic

agents.


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CANDIDATES FOR TOCOLYSIS

No contraindications to drug.

Fetus currently healthy.

Clear diagnosis of preterm labor.

Cervix < 4cm dilatation.

Gestational age between 24 -34 weeks.


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Contraindication of Tocolysis

Severe pregnancy inducedhypertension

Uncontrolled diabetes mellitus

Placental abruption Cardio-pulmoary diseases

Multiple gestation

Maternal hyperthyroidism

Rhesus iso-immunisation

Sickle cell disease.

Severe anaemia.


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Choice Of Tocolytic Drug

Nifedipine =Adalate retard

Atosiban= Tractocile

B Sympathomimetic

(Ritodrine)

Magnesium sulphate Indomethacin = Indocid


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Choice Of Tocolytic Drug

If a tocolytic drug is used, ritodrineno longer seems the

best choice.

Atosiban or nifedipineappear preferable

as they have fewer adverse effects and seem to have

comparable effectiveness.


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B -Sympathomimetic Agents.

Use of beta-agonists should be restricted to the

management of preterm labor between 20 and 35

completed weeks, including women with ruptured

membranes.

(Grade A)


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Side Effects of B -Sympathomimetic

Agents.

Maternal:pulmonary edema, myocardial

ischemia, arrhythmia, and even maternal

death.

Fetal :arrhythmia, cardiac septal

hypertrophy , hydrops, pulmonary edema,

and cardiac failure. hypoglycemia,

periventricular-intraventricular

hemorrhage, and fetal and neonatal death.


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Magnesium sulphate is ineffective at delaying birth or

preventing preterm birth, and its use is associated with an

increased mortality for the infant.

Magnesium Sulphate


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Indomethacin

Compared with ritodrine there is insufficient evidence for any

differential effect on delay in delivery, but indomethacin

does seem to have fewer maternal adverse effects than the

beta-agonistsFetal risk: (Common with high dose and prolonged exposure)

Premature closure of the ductus arteriosus.

Renal and cerebral vasoconstriction.

Necrotising enterocolitis


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Indomethacin

Indomethacin therapy for

< 48 hours

< 30-32 weeks' gestation)

Not > 200mg/day.

appears to be a relatively safe and effective tocolytic agent

Indomethacin can be used as a second-line tocolytic agentin early gestational age preterm labors.


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Indomethacin

Indomethacin may be a first-line tocolytic in:

Associated polyhydramnios:

( to have renal effects of indomethacin)

Capsule 25mg oral

Amp 50mg

Rectal Supp 100 mg

50 mg Loading dose

Then 25-50mg /6hs


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Atosiban: Tractocil

Atosiban, a synthetic peptide, is a competitive antagonist of oxytocinatuterine oxytocin receptors.

Atosiban- compared with beta-agonists- has:

Little difference in the effect of these agents on delayed

delivery

Fewer maternal adverse effectsthan beta-agonists, such as

chest pain, palpitations , tachycardia , hypotension ,

dyspnoea ,vomiting , and headache.


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Nifedipine

Nifedipine- compared with ritodrine - has:

Higher delaying of delivery for >48 H.

Lower risk of RDS &Neonatal jundice.

Lower admission to NICU

Fewer maternal adverse effects

When tocolysis is indicated for women in preterm labor, calcium channel

blockers are preferable to other tocolytic agents compared, mainly

betamimetics.

Further research should address the effects of different dosage regimens

and formulations


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Nifedipine

Dose:

20mg initial

10-20 mg /4-6 h

Available forms

Adalate capsule : 10mg

Adalate retard Tablet: 20 mg


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Group B Streptococci (GBS)Prophylaxis

All patients in preterm labor are considered at high risk for neonatal GBSsepsis and should receive prophylactic antibiotics regardless of culture

status.

ACOG Advises Screening All Pregnant Women for Group B Strep.The goal of this strategy is to prevent neonatal sepsis, and not to prevent

preterm birth.

All patients in preterm labor are considered at high risk for neonatal GBS

sepsis and should receive prophylactic antibiotics regardless of culture

status.


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Management after Tocolysis

If maternal and fetal conditions are stable, can be

managed at home

Avoid excessive physical activity; most advocate pelvic

rest


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Delivery of Preterm Fetus

Every effort for in utero transfer to antertiary care obstetric unit linked with NICU


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Mode of Delivery

If the presentation is Cephalic and normal fetal heart rate

patternVaginal Delivery

No evidence of routine C-section No evidence for elective forceps delivery.

Episiotomy rarely required

If abnormal F.H.R patternC-section

( Hypoxiapelivemtricular leucomalacia)


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Preterm Breech(Obstetric Dilemma)

Mode of delivery of preterm breech will need to be made

on a case to case by obstetrician at that time.

C-section in preterm breech already in vagina may be

more traumatic then vaginal delivery


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Summary Oral metronidazole significantly lowers the risk of

preterm birth, by 60% in high risk women positivefor bacterial vaginosis.

Asymptomatic bacteriuria carries an increased riskof preterm birth, the risk is reduced by appropriated

antibiotic treatment.

Mothers at risk of preterm delivery should bescreened for GBS colonization. If positive, intrapartum antibiotics should be offered.

When based on historical factors alone, cervicalcerclage improves outcomes only in women withthree or more previous very early deliveries.


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continue

A single course of maternal steroids given b/w 28 and 34wks gestation and received within 7 days of deliveryresults in markedly improved neonatal outcomes.

There is no evidence of benefit and some evidence ofharm associated with the use of antibiotics inuncomplicated preterm labor with intact membrane

Th k


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Thanks

preterm labor.ppt

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