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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