Intrapartum fetal survellence

1. INTRAPARTUM FETAL SURVEILLANCE DR. Mohit Satodia DR.BHARTI GOEL

2. GOAL The timely identification and rescue of the fetus at risk of neonatal and long term morbidity from intrapartum hypoxic insult

3. Intrapartum monitoring FHR monitoring – Intermittent auscultation(IA) Electronic fetal monitoring(EFM) Fetal Scalp pH Fetal Pulse oximetry Fetal scalp lactate testing ST waveform analysis

4. FETAL HEART RATE MONITORING External FHR monitoring- Hand-held Doppler ultrasound probe External transducer

5. External FHR monitoring-

6. TECHNICAL CONSIDERATIONS Basis for FHR monitoring is beat to beat recording For practical purposes ,this is possible only when direct fetal electrocardiograms are recorded with a scalp electrode. Paper speed is important. Commonly used are 1,2 or 3 cm/min. 1 cm/min –a) good records for clinical purposes and limiting the cost and amount of paper b)crowding together of the record making baseline variability difficult to interpret .

7. Contd … 3 cm/min- a) useful when record is difficult to interpret at slow speed i.e. during second stage of labor b) waste of paper more

8. Internal FHR monitoring- Spiral electrode attatched to the fetal scalp with a connection to FHR monitor. The fetal membranes must be ruptured, and the cervix must be at least partially dilated before the electrode may be placed on the fetal scalp.

9. Intermittent auscultation In uncomplicated pregnancies . Doppler better than stethoscope. Every 15 - 30 minutes in active phase of first stage and every 5 minutes in second stage Listen in the absence of active pushing and toward the end of the contraction and at least for 30seconds after each contraction ACOG JUlY 2009 CONTINUOUS EFM No benefit in low risk Continuous EFM -when risk factors for present Every 15 minutes in first stage and every 5 minutes during the second stage.

10. Fetal Assessment : IA & EFM Surveillence Acceptable methods Low-Risk Pregnancies High-Risk Pregnancies Intermittent Auscultation * Yes Yes (a) Continuous Electronic Fetal Monitoring (EFM) Yes Yes (b) Evaluation Intervals First-stage Labour 30 min 15 min ( a,b ) Second –stage labour 15 min 5 min ( a,c ) a- before, during and especially after a contraction for 60 sec b- includes evaluation of tracing every 15 min c- evaluation of tracing every 5 min (ACOG & AAP 2007)

11. INDICATIONS FOR CONTINUOUS EFM Antepartum risk factors - Abnormal Doppler umbilical artery velocimetry Suspected IUGR APH HTN / preeclampsia (current pregnancy) DM Multiple pregnancy Uterine scar / previous CS Iso-immunisation Oligohydramnios / polyhydramnios Maternal medical conditions(including severe anaemia , cardiac disease, hyperthyroidism, vascular disease, renal disease)

12. Risk factors during labour - Prolonged rupture of membranes (> 24 hours) Meconium -stained or blood-stained liquor Fetal bradycardia Fetal tachycardia Maternal pyrexia > 38 ˚C Chorioamnionitis Vaginal bleeding in labour Prolonged active first stage of labour (> 12 hours regular uterine contractions with cervical dilatation>3cm) Prolonged second stage of labour .    

13. Other indications Any use of oxytocin whether for induction or for augmentation of labour Before and for at least 20 minutes after administration of prostaglandin Epidural analgesia (immediately after inserting an epidural block)

14. Benefits of EFM over IA- Reduced risk of neonatal seizures(RR 0.50) No benefit over IA- did not reduce perinatal mortality(RR, 0.85) did not reduce the risk of cerebral palsy (RR, 1.74) Risks of EFM- High false-positive results. Increased rates of surgical intervention High interobserver and intraobserver variability COCHRANE 2006

15. Electronic fetal monitoring Various components include -Baseline -Variability -Accelerations -Decelerations

16. External fetal monitoring BASELINE The mean FHR rounded to increments of 5 bpm during a 10-minute segment, excluding: —Periodic or episodic changes —Periods of marked FHR variability —Segments of baseline that differ by more than 25 bpm The baseline must be for a minimum of 2 minutes in any 10-minute segment Normal : 110–160 bpm Tachycardia: > 160 bpm Bradycardia : <110 bpm

17. FETAL HEART RATE MONITORING Baseline Variability Fluctuations in the baseline FHR that are irregular in amplitude and frequency Visually quantitated as the amplitude of peak-to-trough in bpm . Absent —amplitude range undetectable Minimal —0 to5 bpm Moderate (normal) — 6to25 bpm Marked —> 25 bpm

18. Short term variability – small changes in fetal beat to beat intervals under physiological conditions Long term variability- certain periodicity in the direction and size of these changes causes oscillations of fetal heart rate around mean level In FHR tracings short term variability is superimposed over long term variability as minimal deflexions , not interpreted by naked eye, therefore in clinical practice variability means long term variability

19. Long term variability characterized by – frequency and amplitude Frequency is difficult to assess correctly Therefore , variability is usually quantitated by amplitude of the oscillations around baseline heart rate.

20. The tracing shows an amplitude range of ~ 10 BPM (moderate variability ).

21. Factors affecting variability Normal variability : 98% fetuses not acidotic Decreased variability : Fetal metabolic acidosis , CNS depressants, fetal sleep cycles, congenital anomalies, prematurity, fetal tachycardia, preexisting neurologic abnormality, betamethasone . I ncreased variability ( saltatory pattern ): Acute hypoxia or cord compression, eg 2 nd Stage

22. ACCELERATION A visually apparent abrupt increase in the FHR <32 weeks : > 10 BPM above baseline for > 10 sec >32 weeks : > 15 BPM above baseline for > 15 sec Prolonged acceleration lasts >2 min but <10 min in duration. If an acceleration lasts 10 min or longer, it is a baseline change

23. Early Deceleration Symmetrical gradual decrease and return of the FHR associated with a uterine contraction The nadir of the deceleration occurs at the same time as the peak of the contraction. In most cases the onset, nadir, and recovery of the deceleration are coincident with the beginning, peak, and ending of the contraction, respectively

24. Caused by fetal head compression by uterine cervix Usually seen between 4 and 6 cm of dilation

25. Late Deceleration Symmetrical gradual decrease and return of the FHR associated with a uterine contraction The deceleration is delayed in timing, with the nadir of the deceleration occurring after the peak of the contraction. In most cases, the onset, nadir, and recovery of the deceleration occur after the beginning, peak, and ending of the contraction, respectively

26. Associated with uteroplacental insufficiency Causes -Maternal hypotension,postmaturity , DM,HTN

27. Variable Deceleration Visually apparent abrupt decrease in FHR The decrease in FHR is ≥ 15 bpm , lasting ≥ 15 sec, and <2 minutes in duration. When variable decelerations are associated with uterine contractions, their onset, depth, and duration commonly vary with successive uterine contractions.

28. Caused by compression of the umbilical cord . If appearing early in labour -often caused by oligohydramnios

29. TYPES Typical Atypical Loss of shoulders Slow return to baseline Prolonged secondary rise in baseline Loss of variability during deceleration Continuation at lower baseline

30. Classification of the severity of variable deceleration MILD- Deceleration of a duration of <30sec , regardless of depth Deceleration not below 80bpm , regardless of duration MODERATE - Deceleration with a level <80bpm SEVERE - Deceleration to a level <70bpm for >60sec

31. Prolonged Deceleration Decrease from baseline that is 15 bpm or more, lasting ≥ 2 min but <10 min If lasts 10 minutes or longer, it is a baseline change Causes -prolonged cord compression,prolonged uterine hyperstimulation,severe degree of abruptio,eclamptic seizure,following conduction anaesthesia

32. SINUSOIDAL PATTERN Visually apparent, smooth, sine wave-like undulating pattern in FHR baseline with a cycle frequency of 3–5 per minute which persists for 20 min or more. Indicates severe fetal anemia as occurs in Rh isoimmunization Feto maternal hemorrhage Twin twin transfusion syndrome severe hypoxia

33. A

34. Three-Tiered Fetal Heart Rate Interpretation System Category I- NORMAL acid base status • Baseline rate: 110–160 bpm • Moderate Baseline FHR variability • No Late or variable decelerations • Early decelerations:  • Accelerations:  Category II-INDETERMINATE not categorized as Category I or III. Category III-ABNORMAL acid base status-Intervention Absent baseline FHR variability and any of the following: —Recurrent late decelerations —Recurrent variable decelerations — Bradycardia Sinusoidal pattern

35. RCOG CLASSIFICATION BASELINE VARIABILITY DECELERATION ACCELERATION REASSURING 110-160 ≥ 5 bpm None present NON REASSURING 100-109 161-180 < 5 for ≥40 min but <90 min Early decel ; typical variable; single prolonged ≤ 3min ABNORMAL <100 >180 sinusoidal ≥ 10 min < 5 for ≥90 min Late decel ; atypical variable; single prolonged > 3min

36. Ancillary tests that can aid in the management of Category II or Category III FHR tracings- Four techniques are available to stimulate the fetus: 1)fetal scalp sampling, 2) Allis clamp scalp stimulation, 3) vibroacoustic stimulation, and 4) digital scalp stimulation

37. A Cochrane review of three trials concluded that manual fetal manipulation did not decrease NRFS and it is not recommended. Cochrane review of two trials concluded that antenatal maternal glucose administration did not decrease the incidence of NRFS and it is not recommended.

38. Standard interventions for NRFS - Supplemental oxygen Discontinuation of any labor stimulating agent Changing maternal position Resolution of maternal hypotension-hydration. P/V to determine umbilical cord prolapse , rapid cervical dilation, or descent of the fetal head,ARM Assessment of uterine contraction . Tocolytics -in tachysystole with associated FHR changes. When the FHR tracing includes recurrent variable decelerations - Amnioinfusion

39. MANAGMENT Suspicious CTG- If inadequate quality-check contact and connections If hypercontractility -discontinue oxytocin , consider tocolytics Maternal tachycardia,pyrexia,dehydration , hypotension Supine? Epidural? sedation? drugs? i /v crystalloid bolus; 10 L/min O 2 If persistent → do ancillary tests Pathological CTG FBS if feasible If not feasible-expedite delivery (within 30 min)

40. Effects of Medications on FHR Patterns Narcotics- decreased variability and accelerations Corticosteroids- Decreased variability (with beta- methasone but not dexamethasone ) Magnesium sulfate- A significant decrease in short-term variability, clinically insignificant decrease in FHR inhibits the increase in accelerations with advancing gestational age Epidural analgesia- decreased variability and accelerations Terbutaline - Increase in baseline FHR

41. FETAL SCALP PH In women with "abnormal“ fetal heart rate tracings . Cervix needs to be 4-5cm dilated and Vx at -1 st or below pH <7.20 –fetal acidosis: deliver pH 7.20-7.25 – borderline, repeat in 30 min or deliver if rapid fall pH > 7.25 – reassuring, repeat if FH abnormality persists Greater utility of scalp pH is in its high negative predictive value (97–99%).

42. Contraindications Maternal infection (HIV, hepatitis, HSV) Fetal bleeding disorders (e.g. haemophilia ) Prematurity < 34 weeks Face presentation

43. FETAL PULSE OXIMETRY Acidosis: O 2 sat. <30% for >2min Approved by FDA for use in fetuses with NRFS in May 2000 The ACOG currently recommends against its use until further studies are available to confirm its efficacy and safety Insufficient evidence for its use as an adjunct or independent of electronic fetal surveillance.

44. FETAL SCALP LACTATE TESTING Higher sensitivity and specificity than scalp pH > 4.8 mmol /L : acidosis Clinical trial that compared the use of scalp pH to scalp lactate level did not demonstrate a difference in the rate of acidemia at birth, Apgar scores, or neonatal intensive care unit admissions Not recommended for routine use

45. ST WAVEFORM ANALYSIS Method: STAN S31 fetal heart monitor(USFDA) Scalp electrodes The electrical fetal cardiac signal – P wave, QRS complex, and T wave – is amplified and fed into a cardiotachometer for heart rate calculation

46. Restrict fetal ST waveform analysis to those with non reassuring fetal status on EFM The use of ST waveform analysis for the intrapartum assessment of the compromised fetus is not recommended for routine use at this time.

47. THANK YOU