1. Subject:PTL
Dr shakeri

2. Preterm labor Important cause of perinatal mortality & morbidity
50 % of all major neurologic handicaps

3. Increased in survival Use of C.S Regionalization prenatal care
Improved method of mechanical ventilation
Use of surfactant
Improved nutritional therapy

4. Mechanism of labor onset
Hormonal (progestron withdrawal)
Oxytocin
Prostaglandins
Cytokines
IL.1-IL.6-TNF ( stimulate the amnion and decidua to
produce PG)
B-TGF ( inhibit PG production)
Other factors
endothelin
nitric oxide (NOS)

5. Infection as a cause of preterm labor
Linked with symtomatic nongenital infection
Subclinical Infection an important cause of PTL
a- Histologic chorioamnionitis increased
b- recognized infections in mother and neonates
c- sepsis and meningitis are increased 3 to 10 fold
d- positive culture of amniotic fluid/membrane/decidua
3-24% (<32 week)

6. e. Biochemical markers of infection often present f
e. Biochemical markers of infection often present f. Bacteria or their products induce PTL in animal

7. Biochemical marker Amniotic fluid glucose <14 mg/dl Serum WBC CRP
Amniotic or serum cytokines (IL.6 most sensitive marker)

8. Ureaplasma urealyticum ,chlamyclia trachomatis ,GBS in the lower genital tract is not associated with PTL
T.vaginalis is associated with PTL
bacterial vaginosis (anaerobe) PTL X 2-3
Untreated bacteriuria ,PTL X 2

9. Route of upper genital tract infection
Ascending through the vagina and cervix
Hematogenously (placenta-bacteremia from periodontal disease)
Contamination during amniocentesis or cvs
Spread from Abd cavity via the fallopian tubes

10. Important points Among women in PTL with intact membranes
mycoplasma,anaerobic organism and gardnerella
Vaginalis are most commonly found in amniotic fluid
N.Gonorrhoeae and c.trachomatis are rarely found
Ecoli and GBS occasionally found

11. Use of antibiotic to prevent PTL in women with PTL and PROM
With intact membrane
.GBS prophylaxis is indicated
.don’t give AB routinely to prevent PTL
With PROM
.at week ampicillin + erythromycin for 7 days or erythromycin for 10 days

12. Epidemiology Incidence 12% Preterm delivery .PTL 50% .PROM 33%
.cervical incompetence

13. Major preterm labor risk factor
Prior preterm birth *6-8
Multiple gestations *6-8
African american race *3.3
Low socioeconomic status *2-2.6

14. Minor risk factor of PTL
Modifiable risk
.poor maternal weight gain
.physically demanding work
.smoking
.anemia
.bacteriuria
.bacterial vaginosis
.maternal systemic infection (pyelonephritis)

15. Nonmodifiable risk
.extremes of age <17 - >40
.prior multiple abortion
.history of uterin abnormality
.short status
.low pregnancy weight

16. Prediction of woman at risk for PTL
Receive c.s prior to delivery
If necessary ,receive tocolytic
Transported to level 3 perinatal center

17. Criteria for screening tests
Sensitivity ↑
Specificity
Negative predictive value ↑
Positive predictive value
Ascertainment of early, asymptomatic disease
Early treatment alter health outcome
Disease is important ,prevalent

18. Acceptable to population
Diagnosis / treatment available
Simple , reliable , valid
Cost proportional to benefit
Risk scoring systems
contraction monitoring-HUAM
Screening for B.V
Sal-est
Cervical evaluation

19. Fetal fibronectin
presence w strongly associated with PTL
Sensitivity is low –Specificity is high
Used to women with intact membrane, cervical dilation less than 3 cm ,GA w results should be available within 24h
False positive (recent intercourse-vaginal examination presence of B.V -vaginal bleeding)
>50 ng → positive test

20. All of these tests fail to meet the goals of an ideal screening test

21. Preterm labor defined
uterin contractions >4 contractions per 20 minutes
Cervical dilation cm or more in N..P
3cm or more in M.P
Cervical effacement > 80%
Uterin contraction and cervical change

22. treatment Hormonal treatment Alcohol treatment Bmimetics Mgso4
Antiprostaglandin agents
Oxytocin analogs
Ca channel blockers

23. Absolute CI of tocolytic theraphy
Severe preeclampsia
Severe abruptio
Severe bleeding
Frank chorioamnionitis
Fetal death
Fetal anomaly incompatible with live
Severe FGR
Mature lung
Maternal cardiac arrythmia

24. Relative CI to tocolytic therapy
Mild chronic hypertension
Mild abruptio
Stable previa
Maternal cardiac disease
Hyper thyroidism
Uncontrolled diabetes
Fetal distress
Fetal anomaly
Mild IUGR
Cervix dilatation greater than 4 cm

25. B - adrenergic agonists
The most wildly prescribed
Ritodrined and terbutaline (SC-IV)
Disadvantage - side effect(none of them are completely B2 selective (
Negative B2 effect
Maternal hypotension
Decreased u.o.p
increased glucose secretion
Hypokalemia
Pulmonary edema

26. Negative B1 effect
Tachycardia
Palpitation
Constipation
Decreased gastric emptying
Hypokalemia
Agitation
jilleriness

27. Severe maternal adverse effect
Cardiac arrhythmia
Myocardial infraction
Pulmonary edema
Postpartum cardiomyopathy
death

28. Fetal effect
Tachycardia
Increased C.O.P
Redistribution of blood flow
Increased thickness of inter ventricular septum
Neonatal supra ventricular tachycardia
Myocardial ischemia and necrosis
hydrops
Hypoglycemia
Intra ventricular hemorrhage

29. Are B-mimetics efficacious?

30. Magnesium sulfate
In recent years, tocolytic of choice in many delivery units
Protocol of administration
The blood levels of 6-8mg/dl are optimal for tocolysis

31. Maternal side effect
Common (flushing-sense of warmth-headache nystagmus-nausea-dizziness-lethargy)
Serious (pulmonary edema-neuromuscular blockage-
osteopenia-respiratory depression-cardiac arrest)

32. Neonatal side effect
Respiratory depession
Decreased beat to beat variability
Decreased muscle tone
Drowsiness
Depression
Poor respiratory effort
Low apgar score

33. Is mgso4 ?efficacious

34. Ca channel blocker Mechanism Protocol of Ad Maternal side effect
Decrease in mean arterial pressure
Symptomatic hypotension
Nausea-headache-facial flushing

35. Neonatal side effect
Well tolerated by the fetus
Neonatal heart block
Growth restriction , acidosis , stillbirth
No protocol established the safety of using these medication together

36. Prostaglandin synthesis inhibitors
Mechanism
Protocol of Ad
Fetal CI
Growth restriction
Renal anomaly
Oligohydramnios
Chorioamnionitis
Ductal dependant cardiac lesion
Twin to twin transfusion syndrom

37. Maternal CI
Renal and hepatic D
Active peptic ulcer
Poorly control H.T
Asthma in aspirin-sensitive patients
Coagulation disorder
Maternal side effect
GI upset and hemorrhage
Alteration in coagulation
Thrombocytopenia
Renal injury(prolonged treatment)

38. Neonatal side effect
Constriction of ductus arteriosus
Neonatal PHT 5-10%
Oligohydraminous
increased ADH
direct effect on renal blood flow
Necrotizing enterocolitis
Intraventricular hemorrhage

39. Effective agent that is well tolerated by mother and fetus
Indomethacin to be comparable to ritodrine and MgSo4
Exposure should be limited to 48 hrs and G.A less than 32 weeks

40. Other tocolytic agents
Atosiban (analog oxytocin)
Nitroglycerin
Cyclo-oxygenase inhibitor
Progestin
Nitroxide inhibitor

41. Maintenance tocolysis following arrest of PTL
Oral tocolysis with B-mimetic
Continous subcutaneous administration of terbutalin
Oral MgSO4
Oral nifedipine
Long-term tocolysis with prostaglandin synthetases inhibitors is contraindicated

42. در حال حاضر کارایی هیچ کدام از درمانها به عنوان Maintenance tocolytic agent تایید نشده است و همه آنها با عوارض قابل توجه همراه بوده.

43. Ancillary therapy for women in PTL
Antibiotic therapy
Antibiotic therapy in PTL with intact membrane is not indicated
GBS prophylaxis should be administered
Hydration therapy
Bed rest
C.S (all women at risk for PTL prior to 34 weeks receive C.S

44. Key points The rate of PTL is increasing in the united states.
fFN and vaginal ultrasound of cervix and promising technologies to identify women at risk for preterm delivery.
Screening for B.V and T.Vaginal is not indicated.
Management of women with asymptomatic shortening of the cervix controversial
Tocolytic therapy has not been associated with improvements in neonatal outcome.
Weekly courses of antenatal C.S should not be routinely prescribed.
Antenatal progesteron therapy may reduce the risk of preterm birth (PTB) and low birth weight (LBW) in women with previous PTB