Non-stress test (NST)
Fetal acoustic stimulation test (AST, FAST)
Vibroacoustic stimulation test (VAST)
Contraction stress test (CST)
Oxytocin challenge test (OCT)
increments of 5 bpm during a 10-min
segment, excluding:
Periodic or episodic changes
Periods of marked FHR variability
Segments of baseline that differ >25bpm
Normal FHR: 110~160bpm
9
Beat-to-beat variability
Variability is visually quantified as the
amplitude of peak-to-trough in bpm
Absent—amplitude range undetectable
Minimal—amplitude range detectable but≤5
bpm
Moderate—amplitude range 6~25 bpm
Marked—amplitude range >25 bpm
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 minutes or more.
Acceleration
A visually apparent increase in the FHR from the
most recently calculated baseline
Duration: time from initial change in FHR from
the baseline to the return of the FHR to baseline
“Acceleration”
≥32 weeks: ≥15 bpm, duration ≥15 sec
<32 weeks: ≥10 bpm, duration ≥10 sec
,
gradual decrease and
recovery
Onset to nadir ≥ 30
secs
Onset , peak and
ending
with
contraction
Caused by fetal head
compression
with
vagus nerve response
14
<2 min
Usually
associated
with cord compression,
may be associated
with acidosis
16
Variable deceleration Complicated
Nadir < 70 bpm, duration > 60 seconds
Slow return to baseline
Repetitive deceleration 3 times in 20 minutes
Recurrent deceleration with > 50% of uterine
contractions in any 20 minute segment
17
Major Guideline for CTG
ACOG 美國婦產科學院 (2009)
RCOG 英國皇家婦產科學院 ( 2007)
SOGC 加拿大婦產科醫學會 ( 2007 )
RANZCOG 紐澳皇家婦產科學院
AOFOG 亞太婦產科醫學會
Antepartum NST / AST
Results
Reactive / Reassuring
Normal baseline, Moderate variability
Present of 2 accelerations in 20 minutes
No variable or late deceleration
Non-reactive / Non-reassuring
<2 accelerations in 20 minutes over 40 minute
periods
Reactive NST is highly predictive of a low risk of
fetal morality in the subsequent 3-7 days
depending on the indication for fetal testing.
NPV >90%, PPV 50 - 70%.
If non-reactive….
Further evaluation
Biophysical profile
Contraction stress test
Pregnancy termination as indicated
Intrapartum
interpretation
Category I, include all of following:
Baseline 110-160 bpm, Moderate variability, No late or
variable deceleration, Present or absent of acceleration
Category II, not categorize as I or III
Category III, include either:
Absent of baseline variability with recurrent late /
variable deceleration or bradycardia
Sinusoidal pattern
If not category I…
Treatment of maternal hypotension (IV)
Provision of maternal oxygen (O2)
Change in maternal position (Left decubitus
position)
Discontinuation of labor stimulation
Treatment of tachysystole
Delivery if refractory
Medication affects results
Amniotic Fluid Volume
Decreased uteroplacental perfusion may lead
to diminished fetal renal blood flow,
decreased urine production, and ultimately,
oligohydramnios.
Amnionic fluid index < 5 cm or deepest
pocket < 2 cm are acceptable criteria for
oligohydramnios
Contraction Stress Test
Oxytocin challenge test / Nipple stimulation
Goal: 3 contractions of 40-60 sec present in 10
mins
Results:
Negative: no late or significant variable
decelerations
Positive: late decelerations in > 50%
contractions
一位患有紅斑性狼瘡的孕婦,在懷孕 29 週時主訴最近兩
天有規則腹痛和胎動減少及胎心率呈現晚期減速( late
deceleration )的情形發生。最可能的臆斷是:
100( 一 )
A .早產合併胎兒可能缺氧
B .妊娠糖尿病
C .前置胎盤
D .胎死腹中
足月分娩時,下列何者不是發生胎兒窘迫的情形? 100( 一 )
A .胎心出現“晚期減速”
B .臍動脈血流速度波形出現逆流
C .胎心出現“早期減速”
D .臍動脈血流速度波形呈現舒張期無血流
一位 24 歲女性, G2P1 ,妊娠 42 週,待產中胎兒心律發
生「變異減速」( variable deceleration ),則下列診斷
以何者為最可能?97( 一 )
A .胎頭壓迫
B .臍帶壓迫
C .子宮胎盤功能不足
D .胎兒畸形
產前胎兒健康評估方法之敘述,下列何者錯誤? 98( 二 )
A .壓力收縮試驗( contraction stress test )呈現陽性屬
不正常
B .非壓力試驗( nonstress test )一般來說是 2 週做 1 次
C .正常的非壓力試驗定義為在 20 分鐘的測驗內,有 2 次以
上的心跳上升、每次超過平均心跳 15 下以上且每次要持
續 15 秒以上
D .若非壓力試驗做了 90 分鐘以上,仍然呈現 non-reactive
代表可能有週產期的病變
Non stress test
Score 2
Score 0
Reactive
Non-reactive
Fetal breathing
≥ 1 episode ≥ 30
Absent /
sec in 30 mins
Less than 30 mins
Fetal movement
≥ 3 body or limb
movement in 30
mins
2 or less
Fetal tone
≥ 1 in 30 mins
Absent / Extension
with no flexion
Amniotic fluid
volume
Normal
Oligohydramnios
~ Reassuring 分隔線
~
~ Delivery 分隔線 ~
Modified biophysical
profile
Non-stress test + Amnionic fluid volume
Either one did not meet the criteria is
considered abnormal
Less time and labor consuming
False-negative rate 0.08%, False positive rate
of 1.5%
Fetal Death After Normal
BPP
Feto-maternal hemorrhage
Umbilical cord accidents
Placental abruption
Incidence: 1/1000
有關產前胎兒健康評估的生物生理計分法( biophysical
profile ),下列何者錯誤?
102( 二 )
A .胎兒生物物理指標最高分為 12 分
B .胎兒生物物理指標若為 0 分,代表有意義的胎兒酸血症(
fetal acidosis )
C .若分數從原本的 2 或 4 分變成 0 分,表示可更準確的預測
不正常的結果
D .分數 10 分不一定表示胎兒血液 pH 值正常
Uterine artery for placental function
However, most perinatal outcome doesn’t
change while identification of abnormality,
only umbilical artery Doppler is recommend
by ACOG for fetal surveillance
Umbilical Artery Doppler
S/D ratio: most commonly used index
About 4.0 at 20 weeks, 2.0 at 40 weeks
Generally < 3.0 after 30 weeks
Wave form: End diastolic flow
Perinatal mortality
Absent end-diastolic flow: 10%
S
Reversed end-diastolic flow: 33%
D
Middle Cerebral Artery
Hypoxic
fetus attempts brain sparing by
reducing cerebrovascular impedance and thus
increasing blood flow, but no significant
differences in pregnancy outcome compare to
biophysical profile
Useful for detection and management of fetal
anemia of any cause
If PSV > 1.5 MoM
Fetal blood sampling
Transfusion if needed
Ductus Venosus
The best predictor of perinatal outcome
Negative or reversed flow in the ductus
venosus was a late finding because these
fetuses had already sustained irreversible
multiorgan damage due to hypoxemia
Uterine Arteries
Most helpful assessing pregnancies at high
risk of uteroplacental insufficiency
Perinatal benefits of uterine artery Doppler
screening have not yet been demonstrated
Notch indicates increased
resistance
In summary
Antepartum fetal surveillance telling more
about the well-being of the baby
An abnormal result not always mean that the
baby is in trouble. It simply mean that you
need special care or test
23 歲孕婦, G2P1 ,妊娠 35 週,接受檢查,結果如下
圖,其檢查名稱為何?
103( 一 )
A .臍動脈血流速度波形
B .胎兒下腔靜脈血流速度波形
C .胎兒中大腦動脈血流速度波形
D .胎兒下行主動脈血流速度波形
23 歲孕婦, G2P1 ,妊娠 35 週,接受檢查,結果如下
圖,其檢查名稱為何?
103( 一 )
A .臍動脈血流速度波形
B .胎兒下腔靜脈血流速度波形
C .胎兒中大腦動脈血流速度波形
D .胎兒下行主動脈血流速度波形
承上題,其檢查結果最可能為下列何者?
103( 一 )
A.Absence of end-diastolic flow velocity
B.Reversed end-diastolic velocity
C.Decrease of middle cerebral arterial flow
D.Increase of middle cerebral arterial flow
RCOG
Classification
Normal
Suspicious
Pathological
Reassuring
Non-reassuring
Abnormal
SCOG
Classification
Normal
Atypical
Abnormal
Baseline
ACOG
Definition
Normal
The mean FHR rounded to
increments of 5 beats per minute
during a 10-minute segment,
excluding
—Periodic or episodic changes
—Periods of marked FHR variability
—Segments of baseline that differ
by more than 25 beats per minute
RCOG
FHR trace is stable
excluding acceleration
and deceleration in 5 to
10 mins
SCOG
Mean FHR rounded to
increments of 5 beats in 10
-minute segment, excluding
Periodic or episodic
changes or periods of
marked FHR Variability(>25)
110-160 bpm
110-160 bpm
110-160 bpm
Tachycardia
>160 bpm
Moderate 161-180
Abnormal <180
>160 bpm > 10
mins
Bradycaridia
<110 bpm
Moderate 100-109
Abnormal <100
<110 > 10 mins
ACOG
Variability is visually quantitated
as the amplitude of peak-totrough in beats per minute.
—Absent—amplitude range
undetectable
—Minimal—amplitude range
detectable but 5 beats per minute
or fewer
—Moderate (normal)—amplitude
range 6–25 beats per minute
—Marked—amplitude range
greater than 25 beats per minute
RCOG
3-5 cycles / mins
-Reassuring >=5
-Non-reassuring
< for 40-90 mins
-Abnormal
<5 for 90 mins
SCOG
Variability refers to the
fluctuations in the baseline
FHR.
It is determined by choosing
one minute of a 10-minute
section of the FH tracing with at
least 2 cycles/minute (normal is
2 to 4 cycles/minute) that is free
from accelerations and
decelerations, and measuring
the difference between the
lowest and highest rate. The
difference is the range /
amplitude of variability.
Acceleration
A visually apparent abrupt increase (onset to peak in
less than 30 seconds)
>= 32 weeks , > 15 bpm for > 15 secs- 2 mins
< 32 weeks , > 10 bpm for 10 secs- 2mins
ACOG 、 SCOG
• Prolonged acceleration lasts 2 minutes or
more but less than 10 minutes in duration.
• If an acceleration lasts 10 minutes or
longer, it is a baseline change.
Early Deceleration
ACOG
Visually apparent usually symmetrical gradual
decrease and return of the FHR associated with a
uterine contraction
• A gradual FHR decrease is defined as from the
onset to the FHR nadir of 30 seconds or more.
• The decrease in FHR is calculated from the
onset to the nadir of the deceleration.
• 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.
SCOG
They are associated with fetal
head compression during
labour and are generally
considered benign and
inconsequential.
This FHR pattern is not
Normally associated with fetal
acidemia.
ACOG
• The decrease in FHR is calculated from
the onset to the nadir of the deceleration.
• 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
SCOG
Late decelerations are found in
association with Uteroplacental
insufficiency and imply some
degree of hypoxia.
Variable
Deceleration
Nadir <30 secs
Decreased > 15 bpm , <2 mins
Cord pressure
ACOG
• Visually apparent abrupt decrease in
FHR
• An abrupt FHR decrease is
defined as from the onset of the
deceleration to the beginning of
the FHR nadir of less than 30
seconds.
• The decrease in FHR is
calculated from the onset to the
nadir of the deceleration.
• The decrease in FHR is 15 beats
per minute or greater, lasting 15
seconds or greater, and less than
2 minutes in duration.
• When variable decelerations are
SCOG
a visually apparent abrupt
decrease in the FHR with the
onset of the deceleration to
the nadir of less
than 30 seconds.63 The
deceleration should be at
least 15 beats below the
baseline, lasting for at least
15 seconds, but less than 2
minutes in duration
Prolong variable
deceleration
10 mins > de > 2 mins