preterm labour

Category: Education

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pre term labor ppt by dr shabnam naz shaikh


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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.

Preterm labor:

Preterm labor Labor before 37 completed weeks of gestation


TERMINOLOGY Preterm birth:  24-36+6wks Indicated preterm birth Spontaneous preterm birth (3contractions/10 min +cervical changes) Preterm premature rupture of membrane Premature ROM (1 hr or more before onset of labour) PPROM (premature ROM before 37 wks)

Classification of preterm birth:

Classification of preterm birth Mildly preterm birth - 32 - 36 weeks Very preterm birth - 28 - 31 weeks Extremely preterm birth - 24 - 27 weeks

Incidence :

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% <28 weeks

Survival in Premature Infants survival chance is directly proportional to the maturity :

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

Complications of Prematurity:

Complications of Prematurity RDS IVH Feeding difficulties/NEC Apnea PDA Infection Jaundice Hypothermia Neurobehavioral ROP Anemia


Pathogenesis Premature activation of maternal or fetal HPA axis Decidual hemorrhage Inflammation/infection Pathological uterine distention

Slide 10:

Mechanisms For Preterm Labor

Causes of Perterm Birth:

Causes of Perterm Birth

Slide 12:

Can preterm labor be predicted?


Prediction Assessment of risk factors Vaginal examination to assess the cervical status Ultrasound visualization of cervical length and dilatation Detection of fetal fibronectin in cervicovaginal secretions

Risk factors for preterm birth:

Risk factors for preterm birth Relative risk Risk factors

2-Vaginal examination:

2-Vaginal examination Digital examination is the traditional method used to detect cervical maturation, but quantifying these changes is often difficult.

3-Vaginal U/S:

3-Vaginal U/S Vaginal Ultrasonography allows a more objective approach to examination of the cervix.

Sonographic Cervical Length:

Sonographic Cervical Length 80-100% of women who deliver early have cervix <30mm 50% delivery rate within one week have cervix < 15 mm or less

Fetal Fibronectin:

Fetal Fibronectin Fetal Fibronectin (fFN)- it is a glue like protein binding choriodecidual membrane Present in vaginal secretions between 23-34 weeks and 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 mm shows significant risk

Slide 19:

Prevention of preterm labor

Prevention of PTB:

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

Treatment Of Vaginosis :

Treatment Of Vaginosis Treatment of asymptomatic abnormal vaginal flora and bacterial vaginosis with vaginal clindamycin or oral metronidazole early in the 2 nd trimester significantly reduces the rate of late miscarriage and spontaneous preterm birth.

Slide 22:



Three criteria to document PTL(20-37wks) 1-Regular uterine contractions occur at 4/20 min. or 8/60 min. Plus: progressive change in the cervix. 2- Cervical dilatation > 1 cm 3- Effacement > 80%. Diagnosis

Four Questions::

Is the patient in labor? Are the membranes ruptured? Is the fetus preterm? What risk factors are present? Four Questions:


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.


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 .


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.


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.

Slide 29:



MANAGEMENT OF PRETERM LABOUR Prophylactic management Management in labour Management after delivery

Prophylactic Management:

Prophylactic Management Good antenatal care.  All diseases should be controlled well.  In multiple pregnancy rest and sedatives very important  In incompetent Cx.  Circlage stitches.  Diabetic treatment.  Tocolytic therapy

Management of Acute Preterm Labor:

Management of Acute Preterm Labor Sedation and hydaration Bed rest and hydration are commonly recommended, but without proven efficacy. (risk of DVT in bed rest). Probable role of hydration  decrease secretion of ADH + oxytocin from post pitutary Steroids Antibiotics Tocolysis

Role of Steroids:

Role of Steroids Single course of antenatal steroids b/w 24 and 34 wks of gestation with intact membranes and 24-32 wks in PPROM reduces the risk of RDS,IVH, NEC, Sepsis and neonatal mortality by 50%. Dose Betamethasone 12mg i/m B.D for 24 hrs. Dexamethasone 6 mg i/m every 6 hours for 24 hours.

Slide 34:

MOA of steroids. 1. Stimulates type II pneumocyctes to produce surfactant. 2. Structural development of lungs 3. 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

TRH, Vitamine K , Phenobarbitone :

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.

Role of Antibiotics (Oracle Trail):

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.

Is Tocolysis Better Than No Tocolysis For Preterm Labor? :

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


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 delivery and is associated with Significant adverse effect.


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 of tocolytics at or after 34 weeks' . There is no consensus on a lower gestational age limit for the use of tocolytic agents.


CANDIDATES FOR TOCOLYSIS No contraindications to drug. Fetus currently healthy. Clear diagnosis of preterm labor. Cervix < 4cm dilatation. Gestational age between 24 -34 weeks.

Contraindication of Tocolysis :

Contraindication of Tocolysis Severe pregnancy induced hypertension Uncontrolled diabetes mellitus Placental abruption Cardio-pulmoary diseases Multiple gestation Maternal hyperthyroidism Rhesus iso-immunisation Sickle cell disease. Severe anaemia.

Choice Of Tocolytic Drug:

Choice Of Tocolytic Drug Nifedipine = Adalate retard Atosiban= Tractocile B –Sympathomimetic (Ritodrine) Magnesium sulphate Indomethacin = Indocid

Choice Of Tocolytic Drug :

Choice Of Tocolytic Drug If a tocolytic drug is used, ritodrine no longer seems the best choice . Atosiban or nifedipine appear preferable as they have fewer adverse effects and seem to have comparable effectiveness.

B -Sympathomimetic Agents. :

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)

Side Effects of B -Sympathomimetic Agents. :

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.

Slide 46:

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

Nitric Oxide Donors:

Nitric Oxide Donors There is insufficient evidence to support the routine administration of nitric oxide donors (nitroglycerin patch ) in the treatment of preterm labor .


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-agonists Fetal risk: (Common with high dose and prolonged exposure) Premature closure of the ductus arteriosus. Renal and cerebral vasoconstriction. Necrotising enterocolitis


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 agent in early gestational age preterm labors.


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

Atosiban: Tractocil:

Atosiban: Tractocil Atosiban, a synthetic peptide, is a competitive antagonist of oxytocin at uterine oxytocin receptors . Atosiban - compared with beta-agonists- has: Little difference in the effect of these agents on delayed delivery Fewer maternal adverse effects than beta-agonists, such as chest pain, palpitations , tachycardia , hypotension , dyspnoea ,vomiting , and headache.


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


Nifedipine Dose: 20mg initial 10-20 mg /4-6 h Available forms Adalate capsule : 10mg Adalate retard Tablet: 20 mg

Group B Streptococci (GBS) Prophylaxis:

Group B Streptococci ( GBS) Prophylaxis All patients in preterm labor are considered at high risk for neonatal GBS sepsis 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.

Management after Tocolysis:

Management after Tocolysis If maternal and fetal conditions are stable, can be managed at home Avoid excessive physical activity; most advocate pelvic rest

Delivery of Preterm Fetus :

Delivery of Preterm Fetus Every effort for in utero transfer to an tertiary care obstetric unit linked with NICU

Mode of Delivery:

Mode of Delivery If the presentation is Cephalic and normal fetal heart rate pattern  Vaginal Delivery No evidence of routine C-section No evidence for elective forceps delivery. Episiotomy rarely required If abnormal F.H.R pattern C-section ( Hypoxia pelivemtricular leucomalacia)

Preterm Breech (Obstetric Dilemma):

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


Summary Oral metronidazole significantly lowers the risk of preterm birth, by 60% in high risk women positive for bacterial vaginosis. Asymptomatic bacteriuria carries an increased risk of preterm birth, the risk is reduced by appropriated antibiotic treatment. Mothers at risk of preterm delivery should be screened for GBS colonization. If positive, intra partum antibiotics should be offered. When based on historical factors alone, cervical cerclage improves outcomes only in women with three or more previous very early deliveries.

Slide 60:

Hospitalization for bed rest leads to an increase in preterm births . Tocolytics have no significant benefit on perinatal mortality or the prolongation of pregnancy to term, but do reduce the number of women delivering within 48 hours by 40 percent.


continue A single course of maternal steroids given b/w 28 and 34 wks gestation and received within 7 days of delivery results in markedly improved neonatal outcomes. There is no evidence of benefit and some evidence of harm associated with the use of antibiotics in uncomplicated preterm labor with intact membrane



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