PRE-TERM LABOR

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PRE-TERM LABOR
Dr Uma.T Department of Obstetrics and Gynecology
SAT Hospital,Government Medical College
Trivandrum

• Insert Presenters Name

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PRETERM LABOUR

• Def Regular painful uterine contractions after
  20 wks and before 37 wks
• Associated with effacement and dilatation of
  cervix
• Incidence 20 30
• Impact Regarding chance of survival of preterm
  neonate
• - Quality of life achieved.

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AETIOLOGY

• Maternal Characteristics
• Age Low High
• Socioeconomic status Poor
• Physical Activity
• Maternal habits Cigarette, addictions
  Alcohol, Cocaine
• Psychological Stress

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MATERNAL SYSTEMIC DISEASES

• Renal Diseases Acute infection
  asymptomatic bacteruria
• Hypertensive disorders
• Maternal diabetes Hydramnios
• Immunological
• disorder SLE, APLA syndrome

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MATERNAL INFECTIONS

• Febrile illnesses Malaria
• Infective diseases Syphilis, toxoplasmosis
• Chorioamnionitis
• Bacterial vaginosis - PPROM

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UTERINE FACTORS

• Uterine Malformations
• Cervical incompetence
• Previous history of abortion Preterm births
• PREGNANCY COMPLICATIONS
• Multiple pregnancy
• Hydramnios
• Placenta Praevia or abruption
• GENETIC FACTORS

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PATHOGENESIS

• Exact mechansim not known
• Fetus plays synergestic role
• ? PG synthesis stimulated by intrauterine
  infection, haemorrhage, overdistension etc.
• From decidua fetal membranes
• ? Cytokines, IL 6, IL - 1, TNF, PAF produced
  by fetal lungs, kidney

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PREDICTION OF PRETERM LABOUR

• Measuring cervical length using TVS
• At 24 wks Mean cervical length is 35 mm .
• Shortened cervix had ? rate of preterm labour
• Requires special expertise
• History of preterm birth
• Fetal fibronectin in cervicovaginal
  secretions
• Ambulatory uterine contraction testing
• Maternal Salivary estriol not used

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DIAGNOSIS

• Contractions at a frequency of 4 in 20 mts. or 8
  in 60 mts.
• Cervical dilatation more than 1 cm.
• Cervical effacement of 80 or greater.

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MANAGEMENT

• Depends on gestational age and neonatal care
  facilities
• Gestational age between 24 and 34 wks
  administer corticosteroids
• 2 doses of 12 mg betamethasone given
  intramuscularly 24 hour apart.
• If delivery occurs 24 hrs after completion of
  betamethasone and within 7 days, chance of
  respiratory distress less.

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MECHANISM OF ACTION

• Induces proteins that regulate biochemical
  systems in type 2 cells.
• Increases alveolar surfactant, compliance and
  lung volume.
• Adverse effects Short term
• Maternal Pulmonary edema, infections, poor
  diabetic control
• Fetal Nil.

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Epithelial cell
Structural Development
Steroids
Type II Pneumocytes
Apoproteins
surfactant
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Repeated Doses of Steroids?

• Not recommended
• Adverse effects
• Chorioamnionitis.
• Cause early onset neonatal sepsis.
• NND.
• Low birth weight.
• Abnormal psychomotor development.

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Tocolysis in preterm labour

• Does tocolysis prevent preterm labour?
• No clear evidence improve outcome only to
  complete course of corticosteroids or
  inuterotransfer
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  (Evidence A)
• Does tocolysis prevent NND and morbidity ?
• No clear reduction
• 
  (Evidence A)

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INDICATION FOR TOCOLYSIS

• Gestational age less than 37 wks
• Cervical dilatation less than 3 cm
• No history of unclean examination or evidence of
  chorio amnionitis.
• No pregnancy complication like APH, PE
• Fetus normal, alive, no signs of distress.

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COMMONLY USED
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TOCOLYTICS

• Betadrenergic drugs
• Isoxuprine, Riltodrine, salbutamol, terbutaline
• Inhibit uterine contraction by stimulating
  myometrial ß-2 receptors.
• Adverse effects due to stimulation of receptors
  elsewhere.
• Maternal hypotension, Tachycardia, palpitation,
  fetal Tachycardia.

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MAGNESIUM SULPHATE

• High concentration decreases contractility
• Not used for this purpose.
• PROSTAGLANDIN INHIBITORS
• Aspirin, Indomethacin
• Use avoided Premature closure of neonatal
  ductus arteriosus and neonatal pulmonary
  hypertension

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CALCIUM CHANNEL BLOCKERS

• All smooth muscle activity related to free
  calcium in cytoplasm
• Reduction in Calcium inhibits uterine
  contraction.
• Nifedipine Efficacy not been adequately studied.

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Pre-term Labor in Women with a Past History of
PTL
Fetal fibronectin positive women with a prior history of preterm birth Fetal fibronectin positive women with a prior history of preterm birth
Estimated recurrence risk of preterm birth lt35 weeks gestation
Cervical Length 25 mm 65
Cervical Length 26 to 35 mm 45
Cervical Length gt 35 mm 25
Fetal fibronectin negative women with a prior history of preterm birth Fetal fibronectin negative women with a prior history of preterm birth
Estimated recurrence risk of preterm birth lt35 weeks gestation
Cervical Length 25 mm 25
Cervical Length 26 to 35 mm 14
Cervical Length gt 35 mm 07
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Oral Micronized Progesterone Improves Maternal
and Fetal Outcomes in Women with a History of PTL
Reference and study type Intervention (N) Mean GA ? SD (weeks) PTBlt37 weeks () PTB36 weeks () PTB34 weeks () PTB33 weeks () PTB28 weeks ()
Majhi et al.2 (2009), RCT Vaginal (50) NR 12.0 NR 4.0 NR NR
Majhi et al.2 (2009), RCT None (50) NR 38.0 NR 6.0 NR NR
Rai et al.2 (2009), RCT Oral (74) 36.1?2.6 39.2 NR 27.0 2.7 0
Rai et al.2 (2009), RCT Placebo (74) 34.0?3.25 59.5 NR 25.7 20.3 4.0
NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant. NRNot reported. Statistically significant.

• Oral micronized progesterone was associated with
• Improved birth weight (2400 g vs. 1890 g,
  plt0.001)
• Lower stay in the neonatal ICU (plt0.001)
• More favorable Apgar scores (plt0.001)

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Pre-term Labor and Uterine Abnormalities

• Women with uterine anomalies have poorer
  reproductive outcomes when compared to that of
  the general population.
• Unicornuate uterus is associated with the poorest
  fetal survival.
• The incidence of preterm deliveries among women
  with bicornuate uterus and didelphic uterus has
  been reported in as high as one-fourth of the
  pregnancies

Number of pregnancies (n) Preterm deliveries (n)
Unicornuate uterus 393 43.3 (170)
Didelphic uterus 86 24.4 (21)
Bicornuate uterus 56 25.0 (14)
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Vaginal Micronized Progesterone for Prophylaxis
of PTL Results from Cetingoz et al.
Vaginal progesterone (100 mg) administered
between 24 and 34 weeks has the following
outcomes in women with prior pre-term birth, twin
pregnancy and uterine malformations
Placebo () Progesterone ()
Total population Total population Total population
Delivery lt37 weeks 40/70 (57.2) 32 of 80 (40)
Delivery lt34 weeks 17/70 (24.3) 7 of 80 (8.8)
Preterm labor admission 32/70 (45.7) 20 of 80 (25)
History of PTB History of PTB History of PTB
Delivery lt37 weeks 17/34 (50) 9 of 37 (24.3)
Delivery lt34 weeks 9/34 (26.5) 2 of 37 (5.4)
Preterm labor admission 19/34 (55.9) 11 of 37 (29.7)
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Pre-term Labor and Cervical Length Results
from Iams et al.

• Even a small decrease in cervical length between
  the 24th and 28th weeks of gestation was
  associated with an increased risk of preterm
  birth (relative risk, 2.03 95 CI, 1.283.22)

Measures (at 24 weeks) Relative risk
Cervical length 25th percentile (30 mm) as compared to gt 75th percentile 3.79 (95 CI, 2.326.19)
Cervical length 10th percentile (26 mm) as compared to gt 75th percentile 6.19 (95 CI, 3.849.97)7
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Progesterone Preserves Cervical Length Results
from OBrien et al.
Intravaginal progesterone preserves cervical
length
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NEONATAL CARE

• Preterm infants require neonatal intensive care.
• If facilities not available, give corticosteroids
  and refer patient to appropriate higher centre
• INTRAPARTUM MANAGEMENT
• Proper fetal heart rate monitoring
• Delivery RMLE put
• If poor voluntary efforts in second stage
  Outlet forceps.

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