Electronic Fetal Heart Rate Monitoring: Update of the 2008 NICHD guidelines

Catherine Y Spong, MD

Pregnancy and Perinatology Branch, NICHD

National Institutes of Health

Objectives

To describe the origins and goals of EFM To discuss the changes in the 2008 NICHD

Workshop Report on EFM To review the three tier system and its use in

clinical practice

Background 1960’s Continuous EFM introduced into

obstetrical practice Complicated pregnancies

1978: ~66% US women monitored EFM

2002: >85% US women (3.4M) EFM

Hon et al, 1958

Banta & Thacker 1979

Martin et al, 2003

Goals of intrapartum EFM Reduce perinatal deaths and hypoxic brain injury Serve as a screening test for asphyxia that might

result in neurologic damage or fetal death Allow for intervention to avoid asphyxia-induced

brain damage or death

Reduce cerebral palsy

Efficacy: Cochrane Review 12 clinical trials (n=37,000), 2 of high quality

No “non monitoring” studies Most very old

cEFM compared to intermittent auscultation

Alfirevic et al. Cochrane 2006 (3) #CD006066

number (trials) RR 95%CIPerinatal death 33,513(11 trials) 0.85 0.59-1.23Neonatal seizures 32,386( 9 trials) 0.50 0.31-0.80Cerebral palsy 13,252( 2 trials) 1.74 0.97-3.11Cesarean delivery 18,761(10 trials) 1.66 1.30-2.13Operative VD 18,151( 9 trials) 1.16 1.01-1.32

No reduction in cerebral palsy Dramatic increase in cesarean delivery

0

5

10

15

20

25

30

35

1970 1975 1980 1985 1990 1995 2000 2005

Cesarean

Intrapartum

monitoring

US Preventive Task Force Grade: D•No evidence of benefit•Evidence of harm

66% 85% % US women cEFM in labor

Continuous Intrapartum Electronic Fetal Heart Rate Monitoring

Cesarean delivery rate

%

Why? New technology Implemented before evidence of

efficacy Engrained in clinical practice

• Communication• Definitions & guidelines• Organizations

Difficulties with

Standard definitionsResearch Agenda

To develop standardized and unambiguous definitions for fetal heart rate tracings

AJOG 1997;177:1385-90

1997-2008: 2005: ACOG endorsed 1997 document Research Interpretation systems

1997 NICHD: 2 tier RCOG: 3 tier SOGC: 3 tier Parer: 5 tier

SOGC.org

Sponsored by:NICHDACOGSMFM

NICHD SMFM ACOG ACNM AWHONN AAP RCOG CCOG National Cardiovascular

Center - Japan

Groups represented at 2008 Workshop on EFM:

Updated definitions 3 tier categorization Management expanded Research agenda

Objectives of 2008 Workshop

Key Assumptions reaffirmed

The definitions were developed for visual interpretation of FHR patterns.

FHR pattern features: baseline, episodic and periodic

Variability (short& long-term) as single unit Consider other conditions

Gestational age, meds, fetal anemia Evaluate EFM in clinical context

Absent

Minimal

Moderate

Marked

Sinusoidal

FHR Variability assessed as a single unit

Most sensitive indicator of fetal acid base status

- Changes and new additions from 2008 workshop

- Interpretation systems

Highlight

Uterine contractions Baseline fetal heart rate Baseline FHR variability Presence of accelerations Periodic or episodic

decelerations Changes or trends of FHR

patterns over time

Full description of EFM tracing requires qualitative and quantitative description of:

Contractions

Normal: ≤ 5 UC in 10 min Tachysystole: > 5 UC in 10 min

Presence or absence of decelerations Spontaneous and stimulated labor Hyperstimulation and hypercontractility are

to be abandoned.

• # UCs per 10 min window• averaged over 30 min

Copyright © 2009 Wolters Kluwer.

Onset Shape Nadir

Early Gradual Symmetrical Matches UC peak

Variable Abrupt Asymmetrical ≥ 15 bpm lasting ≥ 15 sec but < 2 min

Late Gradual Symmetrical After UC peak

Classifying Decelerations

Variable decelerations Abrupt decrease (<30 sec to nadir) > 15 bpm Lasting 15 sec to < 2 min

Variable deceleration characteristics of unknown clinical significance

Slow return to baseline Biphasic decelerations ‘Reflex’ tachycardia following variable

decelerations Shoulders or overshoots FHR fluctuations in the trough of the

deceleration Grading (mild, moderate, severe)

Require further research investigation

Simple is best Need consistency of FHR description Systems generally agree on the really good

and the really bad Ideally evidence-based

EFM Interpretation Systems

EFM Interpretation Systems 1997 NICHD: 2 tier RCOG: 3 tier

Extensive vetting and peer review National implementation, 50% drop in intrapartum death

rate

SOGC: 3 tier Extensive vetting and peer review

Parer: 5 tier Applied knowledge, interdisciplinary Variability driven

RCOG: 3 tier•Normal•Suspicious•Pathological

Normal tracing

Previously “Reassuring”

Atypical Tracing

Previously “Non-reassuring”

Abnormal Tracing

Previously “Non-reassuring”

Baseline 110-160 bpm Bradycardia 100-110 bpm

Tachycardia > 160 for > 30 to < 80 min

Rising baseline

Bradycardia < 100 bpm

Tachycardia > 160 for < 80 min.

Erratic baseline

Variability 6-25 bpm

≤ 5 bpm for < 40 min.

≤ 5 bpm for 40-80 min. ≤ 5 bpm for > 80 min.

≥ 25 bpm for > 10 min.

Sinusoidal

Decelerations None or occasional uncomplicated variables or early decelerations

Repetitive (≥ 3) uncomplicated variable decelerations

Occasional late decelerations

Single prolonged deceleration

> 2 min. but < 3 min.

Repetitive (≥ 3)complicated variables:

deceleration to < 70 bpm for > 60 secs.

loss of variability in trough or in baseline

biphasic decelerations

overshoots

slow return to baseline

baseline lower after deceleration

baseline tachycardia or bradycardia

Late decelerations > 50% of contractions

Single prolonged deceleration > 3 but < 10 min

Accelerations Spontaneous accelerations present

(FHR increases > 15 bpm lasting > 15 sec (< 32 wks’ increase in the FHR > 10 bpm lasting > 10 sec)

Accelerations present with fetal scalp stimulation

Absence of acceleration with fetal scalp stimulation

Usually absent*

ACTION EFM may be interrupted for periods up to 30 min. if stable

Further vigilant assessment required, especially when combined features present.

Review overall clinical situation, obtain scalp pH if appropriate/prepare for delivery

*Usually absent, but if accelerations are present, this does not change the classification of tracing.

SOGC: 3 tier•Normal•Atypical•Abnormal

SOGC.org

Risk of acidemia, evolution of FHR patterns to more serious risk, and recommended action

Variable Risk of acidemia Risk of evolution Action

Green 0 Very low None

Blue 0 Low Conservative techniques & begin preparation

Yellow 0 Moderate Conservative techniques & increased surveillance

Orange Borderline/acceptably low

High Conservative techniques & prepare for urgent delivery

Red Unacceptably high Not a consideration Deliver

Am J Obstet Gynecol 2007; 26.e3

Parer & Ikeda: 5 tier• Green• Blue• Yellow• Orange• Red

“HomelandSecurity”

Risk categories for fetal acidemia related to FHR variability, baseline, and

recurrent decelerationsMODERATE (NORMAL) VARIABILITYMODERATE (NORMAL) VARIABILITY

NoNo EarlyEarly Mild VDMild VD Mod VDMod VD Sev VDSev VD Mild LDMild LD Mod LDMod LD Sev LDSev LD Mild PDMild PD Mod PDMod PD Sev PDSev PD

TachyTachy BB BB BB YY OO YY YY OO YY YY OO

NormalNormal GG GG GG BB YY BB YY YY YY YY OO

Mild BrdMild Brd YY YY YY YY OO YY YY OO YY YY OO

Mod BrdMod Brd YY YY OO OO OO OO

Sev BrdSev Brd OO OO OO OO OO

MINIMAL VARIABILITYMINIMAL VARIABILITYNoNo EarlyEarly Mild VDMild VD Mod VDMod VD Sev VDSev VD Mild LDMild LD Mod LDMod LD Sev LDSev LD Mild PDMild PD Mod PDMod PD Sev PDSev PD

TachyTachy BB YY YY OO OO OO OO RR OO OO OO

NormalNormal BB BB YY OO OO OO OO RR OO OO RR

Mild BrdMild Brd OO OO RR RR RR RR RR RR RR RR RR

Mod BrdMod Brd OO OO RR RR RR RR

Sev BrdSev Brd RR RR RR RR RR

ABSENT VARIABILITYABSENT VARIABILITYNoNo EarlyEarly Mild VDMild VD Mod VDMod VD Sev VDSev VD Mild LDMild LD Mod LDMod LD Sev LDSev LD Mild PDMild PD Mod PDMod PD Sev PDSev PD

TachyTachy RR RR RR RR RR RR RR RR RR RR RR

NormalNormal OO RR RR RR RR RR RR RR RR RR RR

Mild BrdMild Brd RR RR RR RR RR RR RR RR RR RR RR

Mod BrdMod Brd RR RR RR RR RR RR

Sev BrdSev Brd RR RR RR RR RR

SinusoidalSinusoidal RR

Marked VariabilityMarked Variability YY

VD, Variable decelerations; LD, Late decelerations; PD, Prolonged decelerations; Brd, Bradycardia; Tachy, Tachycardia G, Green; B, Blue; Y, Yellow; O, Orange

Am J Obstet Gynecol 2007; 26.e3

Normal Abnormal “Middle category”

• Equivocal• Indeterminate• Suspicious• Atypical• Intermediate

Three tier classification system

Normal Equivocal

requires ongoing assessment/evaluation

Abnormalrequires urgent action

Three tier classification system

What to call middle category? Atypical – refers to frequency – not a good word,

these are most common, are typical Equivocal – requires further evaluation/assessment Undetermined significance Conundrum Intermediate Indeterminate Numerous curse words

After Extensive Discussion: Concerns about terms:

normal, abnormal, equivocal Concerns about implied action necessary

(e.g., equivocal requires intervention). Final Framework:

Category I (normal) Category II (indeterminate) Category III (abnormal)

Category Inormal

Category IIindeterminate

Category IIIabnormal

Three tier classification system

Category I: Normal Baseline rate:110-160 bpm Baseline FHR variability: moderate Late or variable decelerations: absent Early decelerations: present or absent Accelerations: present or absent

FHR scale(bpm)

Time60 sec.

Toco scale(mmHg)

Moderate variabilityNormal baselineAccelerationsCategory I

Moderate variabilityNormal baselineNo decelerationsAccelerations presentCategory I

Category III: AbnormalEither Absent FHR variability and any of:

Recurrent late decelerations Recurrent variable decelerations Bradycardia

Sinusoidal Pattern for ≥ 20 min

Absent variabilityNormal baselineRecurrent variable decelerationsCategory III

Category II: Indeterminate all FHR tracings not categorized as

Category I or Category III Represent an appreciable fraction of

those encountered clinically

• Moderate variability with bradycardiaModerate variability with bradycardia • Minimal FHR variabilityMinimal FHR variability• Absent variability with no recurrent decelsAbsent variability with no recurrent decels• Recurrent variable decels with moderate variabilityRecurrent variable decels with moderate variability• Recurrent late decels with moderate variabilityRecurrent late decels with moderate variability

Examples

Minimal variabilityRecurrent late decelerationsCategory II

FHR Management Principles FHR correlates with fetal acid-base status

at the time of observation FHR does not predict cerebral palsy Consider evolution over time Consider entire clinical picture

Strongly predictive of normal acid base status

Follow “in a routine manner”

Meaning & Management

Category I: Normal

Predictive of abnormal acid base Prompt evaluation required Resolve the pattern (support measures,

delivery)

Meaning & Management

Category III: Abnormal

Continued reevaluation Additional tests Non surgical interventions

Meaning & Management

Category II: Indeterminate

Acceleration testing Scalp stimulation Vibroacoustic stimulation Transabdominal halogen light

Interventions Stop oxytocin Check for cord prolapse Maternal oxygen Position change Correct hypotension Amnioinfusion (variable decels)

Management interventionsCategory II: Indeterminate

Obstet Gynecol 2009;114:192-202

Incorporated into Practice Bulletin #106 (2009)

New practice bulletin on management in development: [Focus on category II]

The goal: healthy children, mothers & families…

Special thanks to George Macones, MD EFM Workshop ChairSean Blackwell, MD for FHR tracing samples

Partialocclusion

Partialocclusion

Completeocclusion

A A

V

Uterine contraction

FHR(variable deceleration)

Umbilical cord(2 arteries, 1 vein)