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CTG: Antepartum

CTG: Antepartum

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CTG: Antepartum

  1. 1. Aboubakr Elnashar Benha university Hospital, Egypt
  2. 2. Aboubakr Elnashar
  3. 3. Patterns of foetal activity 1.Fetal breathing movements 2.Gross body movements 3.Fine motor movements Aboubakr Elnashar
  4. 4. During the last 10 w of pregnancy: F. breathing movements: 30% of the time Gross body movements: 10% of the time At term: Cycling between activity & quiescence: occurs over a time span of 60 min Activity is highest: in late evening FHR variation: increases during fetal activity f. body movements: FH acceleration Aboubakr Elnashar
  5. 5. Adaptations to hypoxia  Early 1.Reduced FHR reactivity 2.Absence of breathing movements  Late: 1. Reduced body movements and tone 2. Reduced liquor (renal hypoperfusion) Aboubakr Elnashar
  6. 6. Aboubakr Elnashar
  7. 7. The ideal test 1. Quick 2. Easy to perform 3. Interpreted results that are reproducible. 4. Clearly identify the compromised fetus at a stage at which intervention will improve the outcome 5. Not give an abnormal result for a healthy fetus.  Unfortunately, this ideal test does not yet exist! Aboubakr Elnashar
  8. 8. I. Fetal movements counting (FMC) II. FHR recording 1.CTG 2.Non-Stress Test (NST) 3.Contraction StressTest (CST) or Oxytocin Challenge Test (OCT) 4.Nipple stimulation test 5.Vibroacoustic stimulation (VAS) 6.Computerized CTG III. Biophysical Profile (BPP) IV. Doppler Aboubakr Elnashar
  9. 9. FHR recording 1.CTG 2.NST 3.Contraction stress test 4.Nipple stimulation test 5.Acoustic stimulation test 6.Computerized CTG Aboubakr Elnashar
  10. 10. 1. FHR tracings (CTG) METHOD Simultaneous recordings are performed by 2 separate transducers: 1st for FHR 2nd for UC Aboubakr Elnashar
  11. 11. INTERPRETATION 1.Normal/Reassuring Trace  Baseline FHR: 110-150 b/m  Baseline variability: 10- 25 b/m  At least 2 accelerations (>15 beats for> 15 sec in 20 min)  No decelerations. Aboubakr Elnashar
  12. 12. 2. Suspicious/Equivocal Trace.  Baseline FHR: 150-170 b/m or 100-110 b/m  Reduced baseline variability (5-10 b/m for >40 m)  Absence of accelerations for >40 m  Sporadic deceleration of any type.  absence of accelerations  diminished variability  late decelerations with weak spontaneous contractions. Aboubakr Elnashar
  13. 13. Aboubakr Elnashar
  14. 14. Abnormal/Pathological Trace -  Baseline FHR: <100 b/m or > 170 b/m  No area of normal baseline variability  Silent Pattern (<5 b/m) for >40 min  Sinusoidal pattern (oscillation frequency = 2-5 cycles/min, amplitude of 5-15 b/m) for >40 m  No accelerations  Repeated late, prolonged (> 1 minute) severe variable* (>40 b/m) decelerations.  *decelerations vary in depth, vary in duration and vary in timing relative to the uterine activity Aboubakr Elnashar
  15. 15. Tachycardia  Sinusoidal pattern  Late deceleration normal baseline rate at 120 bpm, absent baseline variability, no accelerations late decelerations Aboubakr Elnashar
  16. 16.  variable fetal heart rate decelerations. Reassuring shoulders (accelerations) are obvious before and after each deceleration. baseline tachycardia minimal variability. Aboubakr Elnashar
  17. 17. MANAGEMENT:  Normal/Reassuring Trace – repeat and/or estimate AFI if considered necessary acc to the cl situation and indication for testing.  Suspicious/Equivocal Trace –  Continue for up to 60 min {determine the presence of f rest/activity cycles}.  Further evaluation acc to the cl situation e.g. fetal acoustic stimulation, AFI, BPP, Doppler blood velocity waveform.  Abnormal/Pathological Trace –  deliver if clinically appropriate.  Further evaluation/monitoring if not appropriate to deliver. Aboubakr Elnashar
  18. 18. Advantages: It is the most commonly performed antenatal test for fetal wellbeing. Quick Simple to perform Aboubakr Elnashar
  19. 19. 2. The Non-Stress Test (NST) (Hammacher et al, 1960) Idea: • FHR accelerations: linked closely with f movements {increased sympathetic output}. • The long term variability: {balance between sympathetic & parasympathetic tone} • The short term variability (baseline or bandwidth variability) {parasympathetic tone}. Aboubakr Elnashar
  20. 20. Steps: 1. left lateral recumbent position. 2. Place and adjust the external tocodynamometer and US transducer to obtain the best possible tracing. 3. Instruct the patient to record f movements on the monitor tracing using the event marker. 4. Observe the EFM tracing until the criteria for a reactive test are met (minimum of 20 min and maximum of 60 min). Aboubakr Elnashar
  21. 21.  In the event of lack of f movement, apply stimulation e.g. fetal acoustic stimulator.  Record any relevant clinical information on the EFM tracing e.g. BP T P loss of contact changes in maternal position. Aboubakr Elnashar
  22. 22. Interpretation:  Reactive: 2 accelerations of FHR in 20 min. Each acceleration 15 beat & lasts 15 sec.  Non-reactive: no accelerations in 40 min. Aboubakr Elnashar
  23. 23. •Reactive: increase of FHR to >15 beats/min for > 15 sec following fetal movements Reactive Aboubakr Elnashar
  24. 24. Antenatal maternal glucose administration: not to reduce non-reactive CTG (Cochrane , 2001) Manual fetal manipulation: not to reduce the incidence of non-reactive CTG. (Cochrane , 2001) Reactive nonstress reliable screening indicator of f wellbeing in women presenting with perception of RFM in 3rd T Abnormal pregnancy outcomes: more common when initial CTG was non reactive (Daly et al, 2011) Aboubakr Elnashar
  25. 25. Disadvantages: 1. Interpretation may be difficult & poor agreement between experts in assessing CTG 2. The predictive value of an abnormal NST for perinatal morbidity & mortality:<40% (Devoe et al, 1985) Aboubakr Elnashar
  26. 26. 3. No significant effect on perinatal outcome (MA of 13 trials) Trend towards increased perinatal mortality (SR of 4 RCT) (Cochrane library, 2001) NST should not be relied upon as the sole means of establishing f wellbeing {Ia} Aboubakr Elnashar
  27. 27. 3. The Contraction Stress Test (CST) or Oxytocin Challenge Test (OCT) 1972: First introduced by Ray 1975: Freeman introduced the parameters of contraction number and frequency to standardize the test. Aboubakr Elnashar
  28. 28. Idea: It is a test of the uteroplacental unit. If fetal oxygenation is marginal at rest, it will transiently worsen with uterine contractions: hypoxemia: late decelerations. If variable decelerations were seen, one should suspect oligohydramnios. Aboubakr Elnashar
  29. 29. Steps: Semi-fowlers position. If the patient is not having spontaneous contractions, pitocin is begun at 0.5-1.0 mU and increased /15-20 minutes until 3C/10 min. Aboubakr Elnashar
  30. 30. Interpretation: Negative: no decelerations with the 3 contractions in the 10 minute window. Positive: late decelerations with 50% or more of the contractions. Suspicious: intermittent late decelerations or severe variable deceleration. Unsatisfactory: <3 contractions or hyperstimulation. Aboubakr Elnashar
  31. 31. •Non-reactive NST followed by CST: mild late decelerations. Aboubakr Elnashar
  32. 32. CST: negative Aboubakr Elnashar
  33. 33. 1. Negative No deceleration 2. Positive transient decelerations Aboubakr Elnashar
  34. 34. Relative contraindications: 1. Preterm labor or certain patients at high risk of preterm labor 2. Preterm membrane rupture 3. History of extensive uterine surgery or classical cesarean delivery 4. Known placenta previa Aboubakr Elnashar
  35. 35. The role of this technique has yet to be established it has been associated with reports of fetal death in cases of unrecognized severe fetal compromise [E]. Aboubakr Elnashar
  36. 36. Sequence Of Events With Placental Insufficiency or Hypoxia 1. Positive CST= late deceleration in 50% of UC. 2. Non reactive NST= No HR acceleration 3. Cessation of fetal movement 4. Basal line tachycardia > 160 bpm 5. Basal line bradycardia <110 bpm Aboubakr Elnashar
  37. 37. 5. VIBROACOUSTIC STIMULATION (VAS) Idea: Vibroacoustic stimulator wakes a sleeping fetus: changing its behavioral state. How to perform: Artificial larynxes that generate sound pressure levels of approximately 80 to 100 decibels is applied in two or three one-second bursts to the maternal abdomen near the fetal head. Aboubakr Elnashar
  38. 38. Advantages: 1. Easy, relatively inexpensive way to shorten testing times and reduce the false-positive rates for NST & biophysical profiles. 2. Fetuses that respond to VAS with an acceleration on NST or a startle response on FBP: very low rates of death within one week of the test. 3. Decrease the incidence of non- reactive CTG and reducing the testing time (The Cochrane Database of Systematic Review, 2001) Aboubakr Elnashar
  39. 39. 6. Computerized CTG • To improve the objectivity of antenatal CTG • The program unlike conventional CTG, allows measurement of short term variability (STV). • STV=variation measured in 3.75 s epochs. • FHRV: better predictor of fetal compromise than the acceleration or decelerations. • Likelihood of metabolic acidaemia or IUFD can be calculated according to the STV. Aboubakr Elnashar
  40. 40. Aboubakr Elnashar
  41. 41. Conventional Vs computerized CTG 1.Fewer additional fetal tests 2.Less time in testing. 3.The study was not large enough to demonstrate any effect on perinatal morbidity or mortality. Aboubakr Elnashar
  42. 42. III. The Biophysical Profile (BPP) First described by Manning in 1980. Idea: Sequence of fetal deterioration 1. Late decelerations appear (CST) 2. Accelerations disappear (NST, BPP, CST) 3. F breathing stops (BPP) 4. F movement stops (BPP) 5. F tone absent (BPP) 6. A F decreases {chronic hypoxia: redistribution of cardiac output away from the kidneys toward the brain}: AFV is a quick evaluation of long term uteroplacental function as in the late 2nd and all the 3rd trimester {AF is essentially fetal urine}. Aboubakr Elnashar
  43. 43. OBSERVATION CRITERIA FOR PRESENT CRITERIA FOR NEGATIVE F Tone 1 episode of flexion- extension-flexion in 30 min No episodes of flexion- extension-flexion in 30 minutes F Movement 3 gross body movements in 30 min Less than 3 gross body movements in 30 minutes F Breathing 1 episode of rhythmic breathing in 30 min No episodes of rhythmic breathing in 30 minutes A FV One 2 centimeter pocket measured in two perpendicular planes A pocket measuring less than 2 centimeters NST Reactive test Non-reactive test Two points are given if the observation is present and zero points are given if it is absent. Aboubakr Elnashar
  44. 44. Interpretation: 8: reassuring. 6: equivocal: repeat within 24 h. 4 or less: positive test: strongly suggests preparing the patient for delivery. Aboubakr Elnashar
  45. 45. Modifications 1. BPP Manning (1990) NST AFV Fetal breathing. less cumbersome results are just as predictive. Aboubakr Elnashar
  46. 46. 2. Placental grading has been incorporated in the BPP to give an overall score out of 12 rather than 10. Aboubakr Elnashar
  47. 47. 3. The most powerful components: •AFI: indicator of long term uteroplacental function •NST: short term indicator of fetal acid-base status. assessment of fetal well-being using these two tools alone may well be as effective as formal BPP Aboubakr Elnashar
  48. 48.  Advantages: 1. In high-risk:  observational studies: effective  {good negative predictive value (99.9%) i.e. fetal death is rare in women with a normal FBP  rarely abnormal when Doppler findings were normal}. Aboubakr Elnashar
  49. 49. 2. In pre-labour rupture of the membranes {fetal breathing movements is reduced in the presence of chorioamnionitis} But sensitivity for abnormal BPP in the presence of chorioamnionitis is 25%[B]: value of BPP is limited Aboubakr Elnashar
  50. 50.  Disadvantages: 1. Difficult and time-consuming 2. False-positive rate: 70%: increased rates of unnecessary intervention. 3. Systematic review of five RCTs: failed to demonstrate any significant benefit of BPP on pregnancy outcome when compared to NST Aboubakr Elnashar
  51. 51. 4. In low risk: cannot be recommended for routine monitoring 5. In high Risk: positive predictive value of 35% (observational study) No enough evidence from RCTs (Cochrane Systematic Review, 2000).: cannot be recommended for routine monitoring for primary surveillance in SGA Aboubakr Elnashar
  52. 52. Statistical Characteristics of Selected Antepartum Fetal Tests Characteristic NST CST BPP Specificity Poor Average High Specificity High High High False-positive rate High High High False-negative rate Low Low Average Aboubakr Elnashar
  53. 53. CONCLUSIONS Aboubakr Elnashar
  54. 54. 1. CTG, must not form the sole basis for the assessment of the fetus. 2. Computerized CTG may well be more effective than standard CTG. 3. Formal assessment of the BPP does not appear to hold any advantage over assessment of liquor volume alone. 4. Where fetal growth restriction is suspected, fetal biometry and assessment of umbilical artery waveforms by Doppler ultrasonography should be incorporated. Aboubakr Elnashar
  55. 55. Aboubakr Elnashar Aboubakr Elnashar

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