The document provides definitions and descriptions of key terms used in cardiotocography (CTG) including: - Baseline heart rate, acceleration, deceleration, variability - Reactive, bradycardia, tachycardia traces - Decreased variability, sinusoidal patterns - Early, late, variable decelerations - Prolonged deceleration - Suspicious/equivocal and pathological/ominous CTG traces Clinical scenarios are presented involving pregnant women in labor with varying cervical dilation and fetal heart rate patterns on CTG monitoring. Uterine hyperstimulation is also defined.

1. BASIC CTG TEACHING SALSO Sarawak General Hospital

2. BASELINE HEART RATE mean level of FHR when stable, acceleration and deceleration being absent Normal = 110 – 160 bpm

3. ACCELERATION A transient increase in FHR of 15 bpm or more and lasting for 15 seconds or more

4. DECELERATION A transient episode of slowing of FHR below the baseline level more than 15 bpm and lasting 15 seconds or more

5. VARIABILITY Degree to which the baseline varies within a particular band width excluding acceleration and deceleration (5-15 bpm) Represent interaction of nervous system which determine the cardiac output and heart rate, in response to venous return and metabolic demands of fetus

6. REACTIVE TRACE Normal baseline heart rate, variability, presence of acceleration (2 in 20 minutes trace) and absence of deceleration

8. BRADYCARDIA A baseline FHR persistently low than 110 bpm Causes : Gestational age > 40 w Cord compression/prolapsed Congenital heart malformation Drugs Late fetal hypoxia unknown

10. TACHYCARDIA Persistantly baseline > 160 bpm Causes : Maternal pyrexia Fetal infection Chronic hypoxia Hyperthyroidism or maternal stress Fetal hormones in response to stress Gestational age < 32 w Drugs Excessive fetal movements

12. DECREASE VARIABILITY Variability < 5 bpm or absent Causes : Severe hypoxia Fetal sleeping pattern Maternal sedation Gestational age < 28 – 30w Congenital malformation

14. SINUSOIDAL A smooth, wave like baseline, absent beat to beat variability Causes : Severe hypoxia Anaemic fetus idiopathic

16. EARLY DECELERATION Onset of deceleration is at the onset of contraction Causes : Fetal head compression

18. LATE DECELERATION Deceleration occur more than 15 seconds after the peak of contraction Causes : Reduction in placental blood flow (abruptio, hyperstimulation) Maternal related disease (PIH) Fetal compromised (IUGR, premature) Supine hypotension

20. VARIABLE DECELERATION Deceleration that inconsistent in shape and in timing with uterine contraction Causes : Umbilical cord entanglement Cord round neck True knot Cord prolapsed

21. PROLONGED DECELERATION A consistent drop in fetal heart rate > 30 bpm, lasting 2 minutes Causes : Total umbilical cord occlusion Uterine hypertonic Maternal hypotension Cord compression

23. SUSPICIOUS/EQUIVOCAL CTG Absence of acceleration for > 40 min BHR 160-170 bpm or 100-110 bpm Absent BV for >40 min with normal baseline and no deceleration Variable deceleration <60 bpm for 60 sec Transient bradycardia <100 bpm more than 2 min

24. PATHOLOGICAL/OMINOUS BHR >160bpm with absent variability and/or repetitive late or variable deceleration Absent BV >90min Complicated variable deceleration (>60 bpm lasting >60 sec) Repetitive late decelerations Prolonged bradycardia Sinusoidal pattern

25. APPROACH TO CTG (DR C BRAVADO) D efine r isk : low/risk C ontraction : freq/duration B aseline r ate : brady/tachy/normal V ariability : 5 – 10 bpm A cceleration : present/absent D eceleration : early/variable/late O verall : comment & management

26. CLINICAL SCENARIO

27. CASE 1 16 y old, G2P0 at 40w came with contraction pain. A/N uncomplicated Os 5cm, ARM clear liquor

29. CASE 2 25 y, G1P0 at 40w + 11 days presented with contraction pain. At this time, os 2cm well effaced

31. Case 3 23 y old, G3P1 at 37 weeks came with contraction pain. She also PIH on treatment. Os 4cm, ARM minimal liquor

33. CASE 4 26, G2P1 at 41w Os already 7cm, clear liquor Good labour progress Os become full then CTG show :

35. Case 5 25, G1P0 at 40w admitted with contraction Os 3cm, clear liquor and given pethidine as pt restless

37. Case 6 25, G1P0 at 40 w had contraction pain At that time os 7cm, clear liquor. 2 hours later progress to os 8 cm

39. UTERINE HYPERSTIMULATION Contraction lasting longer than 90 sec Relaxation between contractions less than 30 sec Contractions more frequent than every 2 minutes (>5 in 10 min) Peak pressure of contraction above 80 mmhg

40. INTERVENTIONS Continuous CTG monitoring Discontinue/reduce oxytocin infusion Increase rate of IVF Change maternal position Oxygen FBS to assess fetal wellbeing Tocolytic drug