FETAL ASSESMENT Flashcards
Techniques employed today to forecast fetal wellbeing focus on fetal biophysical indings that include heart rate,
movement, breathing, and amnionic luid production. These
Findings aid __________ to prevent fetal death
and avoid unnecessary interventions.
antepartum fetal surveillance
Indeed, ___________ -a true negative test-for
most of the tests described are 99.8 percent or higher.
negative-predictive values
In
contrast, estimates of the ___________ -a true
positive test-for abnormal test results are low and range
between 10 and 40 percent.
positive-predictive values
Passive unstimulated fetal activity commences as early as
_________ and becomes more sophisticated and coordinated by the end of pregnancy
7 weeks’ gestation
Indeed, beyond __________, fetal body movements are
never absent for periods exceeding 13 minutes
8 menstrual weeks
Between _____________, general body movements
become organized, and the fetus starts to show rest-activity
cycles
20 and 30 weeks’ gestation
Fetal movement maturation continues
until approximately ________, when behavioral states are established in most normal fetuses
36 weeks
_______ is a quiescent state-quiet sleep-with a narrow
oscillatory bandwidth of the fetal heart rate
State 1F
_______ includes frequent gross body movements, continuous eye movements, and wider oscillation of the fetal heart rate.
State 2F
This state is analogous to rapid eye movement (EM)
or active sleep in the neonate.
State 2F
________ includes continuous eye movements in the absence
of body movements and no heart rate accelerations
State 3F
_______ is one of vigorous body movement with continuous
eye movements and heart rate accelerations. his state corresponds to the awake state in newborn
State 4F
Fetuses spend most of their time in ______ and _______.
states IF and 2F
At _______, 75 percent of time is spent in these two
states (State 1F and 2F).
38 weeks
These behavioral states-particularly IF and 2F, which correspond to _______ and ______ -have been used to develop
an increasingly sophisticated understanding of fetal behavior
quiet sleep and active sleep
In a
study of fetal urine production, bladder volumes increased during
___________.
state IF quiet sleep
During ______, the fetal heart rate
baseline bandwidth increased appreciably, and bladder volume
was significantly diminished due to decreased urine production
and infrequent fetal voiding.
State 2F
An important determinant of fetal activity appears to be
__________, which are independent of maternal ones.
sleep-awake cycles
Fetal sleep cyclicity varies from approximately _________ to
as much as _________
20 minutes
75 minutes
In one study, the mean length of the
quiet or inactive state for term fetuses was _________.
23 minutes
___________ is another
important determinant of fetal activity
Amnionic fluid volume
Sadovsky and coworkers ( 1 979b) classified fetal movements into three categories according to both maternal perceptions and independent recordings using ________.
piezoelectric
sensors
_____, _____ and ________ were described,
and their relative contributions to total weekly movements
throughout the last half of pregnancy were quantified.
Weak, strong, and rolling movements
________ may be a harbinger of impending fetal
death
Diminished fetal activity
To quantfiy fetal movement, clinical
methods include use of:
uterine contraction tocodynamometer
visualization with sonography
maternal subjective
perceptions.
Fetal motions lasting more than _________ were more likely to be identified than shorter episodes
20 seconds
Commonly, women may present in the ________ complaining of subjectively
reduced fetal movement
third trimester
_________ were employed if sonographic scans for
fetal growth or Doppler velocimetry were abnormal.
Fetal heart
rate monitoring tests
Another interesting feature of fetal respiration was _______________.
paradoxical chest wall movement
One interpretation of the paradoxical respiratory motion might be ________ to clear amnionic fluid debris.
coughing
During inspiration, the chest wall paradoxically ______ and the abdomen ______.
collapses
protrudes
During expiration, the chest wall _______
expands
The first are gasps or sighs which occurred at a frequency of ____ per minute.
1 to 4
The second ___________, occurred at rates up to ______ cycles per minute.
Irregular bursts of breathing
240
These rapid respiratory movements
were associated with rapid eye movement.
Irregular bursts of breathing
They suggested that
fetal respiratory rate declined in conjunction with increased
respiratory volume at _________ and coincidental with
lung maturation.
33 to 36 weeks
Many investigators have examined fetal breathing movements using _________ to determine whether chest wall movements might reflect fetal health.
sonography
Several variables in addition
to hypoxia were found to afect fetal respiratory movements.
These included: -during which it is normal
for respiration to cease.
hypoglycemia sound stimuli cigarette smoking amniocentesis impending preterm labor gestational age fetal heart rate labor (normal for respiration to cease)
Because fetal breathing movements are ______, interpretation of fetal health when respirations are absent may be tenuous
episodic
Total
absence of breathing was observed in some of these normal fetuses
for up to ________, indicating that fetal evaluation to diagnose
absent respiratory motion may require long periods of observation
122 minutes
Most clinical
applications have included assessment of other fetal biophysical indices, such as __________.
heart rate
Fetal breathing has become a component of the __________.
biophysical profile
Contractions
also may produce a pattern of variable decelerations as a result of cord compression, suggesting __________, which is often a
concomitant of placental insufficiency.
oligohydramnios
Ray and colleagues ( 1972) used this concept in 66 complicated pregnancies and developed the oxytocin challenge test, which
was later called the ___________.
contraction stress test
_________ is
used to stimulate contractions
Intravenous oxytocin
The criterion for a positive test result that is an abnormal result is ____________.
uniform repetitive late fetal heart rate decelarations
A major disadvantage is that the average contraction
stress test requires _________ to complete.
90 minutes
If at least _____ spontaneous contractions of _________ are
present in ________, no uterine stimulation is necessary.
three
40 seconds or longer
10 minutes
Contractions are induced with either _________ or ________
if there are fewer than three in 10 minutes.
oxytocin or nipple stimulation
For oxytocin use, a
dilute intravenous infusion is initiated at a rate of _______ and
doubled every _________ until a satisfactory contraction pattern is
established
0.5 mU/min
20 minutes
____________ to induce uterine contractions is usually successful for contraction stress testing.
Nipple stimulation
This
__________ ideally will induce a pattern of
three contractions per 10 minutes
2-minute nipple stimulation
If not, after a ________
interval, she is instructed to retry nipple stimulation to achieve
the desired pattern. I
5-minute
Freeman (1975) and Lee and colleagues (1975) introduced the
_________ to describe fetal heart rate acceleration in response to
fetal movement as a sign of fetal health.
nonstress test
This test involved the use
of Doppler-detected fetal heart rate acceleration coincident with
fetal movements perceived by the mother.
nonstress test
no late or significant variable decelerations
Negative
late decelerations following 50% or more of contractions (even if the contraction frequency is fewer than three in
10 minutes)
Positive
Intermittent late decelerations or significant variable decelerations
Equivocal-suspicious
fetal heart rate decelerations that occur in the presence of contractions more frequent than
every 2 minutes or lasting longer than 90 seconds
Equivocal-hyperstimulatory
fewer than three contractions in 10 minutes or an uninterpretable tracing
Unsatisfactory
he nonstress test was easier to perform, and normal results
were used to further discriminate __________.
false-positive contraction stress
tests
the nonstress test is primarily a test of ________ and it differs from the contraction stress test, which is
considered a test of _________
fetal condition
uteroplacental function
Currently, ________ is the most widely used primary testing method for assessment of fetal well-being.
nonstress testing
__________ is also under the control of the autonomic nervous system.
Beat-to-beat variability
Consequently, pathological loss of fetal heart rate acceleration
may be seen in conjunction with significantly ______ beat-to-beat variability
decreased
Loss of such reactivity,
however, is most commonly associated with ________. It also
may be caused by __________ from medications or __________.
sleep cycles
central depression
cigarette smoking
The nonstress test is based on the hypothesis that the heart
rate of a fetus that is not acidemic as a result of hypoxia or
neurological depression will temporarily accelerate in response
to _________.
fetal movement
Fetal movements during testing are identified by ___________ and recorded.
Maternal perception
As ________ develops,
these fetal heart rate accelerations diminish
hypoxia
_________ influences acceleration or reactivity of the fetal heart rate.
Gestational age
In fetuses at or beyond _____ weeks’ gestation, the acceleration acme is ____ bpm or more
above the baseline rate, and the acceleration lasts _________ or longer but less than __________.
32
15
15 seconds
2 minutes
Before 32 weeks, normal accelerations are defined as having an acme that is \_\_\_\_ bpm or more above baseline for \_\_\_\_\_\_\_ or longer.
10
10 seconds
Criteria to define normal nonstress test results differ. They vary regarding the _______, ________, __________, _________.
number
amplitude
duration of accelerations
test duration
The definition recommended
by the American College of Obstetricians and Gynecologists
(20 1 6) requires two or more accelerations peaking at _____ bpm
or more above baseline, each lasting ____ seconds or more, and all
occurring within _______ of beginning the test
15
15
20 minutes
It is also recommended that accelerations with or without fetal
movements be accepted, and that a ________ or longer tracing-to account for fetal sleep cycles-should be performed
before concluding that fetal reactivity is insufficient
40-minute
Because healthy fetuses may not move for periods of up to 75 minutes, some have considered that a longer duration of nonstress testing might increase the \_\_\_\_\_\_\_\_\_ of an abnormal, that is, nonreactive, test
positive-predictive value
In this scheme, either the test became ______ during a period up
to 80 minutes or the test remained ________ for 1 20 minutes, which indicated
that the fetus was very ill.
reactive
nonreactive
An ____________ is not always ominous and
can be seen with a sleeping fetus.
abnormal nonstress test
Importantly, a normal nonstress test can become
abnormal if the fetal condition _________.
deteriorates
Devoe and coworkers (1985) concluded
that nonstress tests that were nonreactive for _______ were
almost invariably - 93 percent-associated with significant perinatal pathology.
90 minutes
This pattern consisted of a fetal heart
rate baseline that oscillated less than 5 bpm and presumably
indicated absent acceleration and beat-to-beat variability.
silent oscillatoy pattern
Visser and associates ( 1 980) described a terminal cardiotocogram which included:
(1) baseline oscillation of less than 5 bpm
(2) absent accelerations
(3) late decelerations with spontaneous uterine contractions
Fetal-growth restriction
75%
Oligohydramnios
80%
Fetal acidemia
40%
Meconium
30%
Placental infarction
93%
Set originally rather arbitrarily at ______, the interval between
tests appears to have been shortened as experience evolved
with nonstress testing.
7 days
According to the American College of
Obstetricians and Gynecologists (20 1 6), more frequent testing
is advocated by some investigators for women with:
postterm pregnancy multifetal gestation pregestational diabetes fetal-growth restriction or pregnancy hypertension
_________ commonly produce heart rate decelerations
Fetal movements
Variable decelarations if NONREPETITIVE AND BRIEF - less than _________ - do not indicate fetal compromise or the need for obstetrical intervention.
30 seconds
REPETITIVE variable decelerations - at least ______ in ________ - even if mild, have been associated with a greater risk of cesarean delivery.
3
20 minutes
Decelerations lasting ________ or longer have been reported to have an even worse prognosis.
1 minute
Severe variable decelerations during a nonstress test plus an amniotic fluid index (AFI) _______ resulted in a 75% cesarean delivery.
> 5 cm
Smith and associates (1987) performed a detailed analysis of the causes of fetal death within 7 days of normal nonstress tests. The most common indication for testing was _________.
postterm pregnancy
The mean interval between testing and death was _____ with a range of 1 to 7 days.
4 days
The single most common autopsy finding was ____________, often associated with some type of umbilical cord abnormality.
Meconium aspiration
They concluded that an ___________ had provoked fetal gasping.
Acute asphyxial insult
Other ascribed frequent causes of fetal death included:
- intrauterine infection
- abnormal cord position
- malformations
- placental abruption
Loud external sounds have been used to startle the fetus and thereby provoke heart rate acceleration - an ______________.
acoustic stimulation nonstress test
A commercially available acoustic stimulator is positioned on the maternal abdomen, and a stimulus of __________ is applied. This may be repeated up to ____ times for up to ____ seconds.
1 to 2 seconds
3
3
A ________ response is defined as the RAPID appearance of a qualifying acceleration following stimulation.
Positive
In a randomized trial of 113 women undergoing nonstress testing, __________ shortened the average time of testing from _______ minutes.
Vibroacoustic stimulation
24 to 15 minutes
Laventhal and colleagues (2003) reported that _______ could be provoked with vibroacoustic stimulation.
fetal tachyarrhythmia
Manning and colleagues (1980) proposed the combined use of five fetal biophysical variables as a more accurate means of assessing fetal health than a single element. Typically, these tests require __________ of examiner time.
30 to 60 minutes
The five fetal biophysical components assessed:
(1) heart rate acceleration
(2) breathing
(3) movements
(4) tone
(5) amnionic fluid volume.
NORMAL variables were assigned a score of ____ each and ABNORMAL variables were given a score of ____.
2
0
Thus, the highest score possible for a normal fetus is _____.
10
Maternal medications such as _____ and ______ can significantly lower the score.
Narcotics
Sedatives
Ozkaya and associates (20 1 2) found that biophysical test scores were higher if a test was performed in ___________ - 20:00 to 22:00 hours - compared with 08:00 to 1 0:00 hours.
late evening
Score 2 Nonstress test
> 2 accelerations of > 15 beats/m in for >15 sec with in 20-40 min
Score 0 Nonstress test
o or 1 acceleration with in 20-40 min
Score 2 Fetal breathing
> 1 episode of rhythmic breathing lasting >30 sec with in 30 min
Score 0 Fetal breathing
<30 sec of breathing with in 30 min
Score 2 Fetal movement
> 3 discrete body or limb movements with in 30 min
Score 0 Fetal movement
<3 discrete movements
Score 2 Fetal tone
> 1 episode of extremity extension and subsequent return to flexion
Score 0 Fetal tone
0 extension/flexion events
Score 2 Amniotic fluid volume
A pocket of amnionic fluid that measures at least 2 cm in two planes perpendicu ar to each other (2 x 2 cm pocket)
Score 0 Amniotic fluid
Largest single vertical pocket <2 cm
Further evaluation warranted, regardless of biophysical composite score, if largest vertical amnionic fluid pocket _____.
< 2 cm
Defined by an antepartum death of a structurally normal fetus of approximately 1 per 1000.
False - normal test rate
The most common identifiable causes of fetal death after
a normal biophysical profile include:
fetomaternal hemorrhage
umbilical cord accidents
and placental abruption
A biophysical score of 0 was almost invariably associated with significant _______.
fetal acidemia
A normal score of 8 or 10 was associated with _______.
Normal pH
An equivocal test result - a score of ____ - was a poor predictor of abnormal outcome.
6
As the abnormal score dropped from 2
or 4 down to 0, this decline was a more accurate predictor of ______.
Abnormal fetal outcome
Biophysical profile score 10 interpretation
Normal, nonasphyxiated fetus
Biophysical profile score 10 recommended management
No fetal indication for intervention; repeat test weekly except in diabetic patients and postterm pregnancy
(twice weekly)
8/10 (Normal AFV) interpretation
Normal, nonasphyxiated fetus
8/8
(NST not done)
8/10 (decreased AFV) interpretation
Chronic fetal asphyxia suspected
8/10 (decreased AFV) recommended management
Deliver
6 interpretation
Possible fetal asphyxia
6 recommended management
If amnionic fluid volume abnormal, deliver
If normal fluid at > 36 weeks with favorable cervix, deliver
If repeat test <6, deliver
If repeat test >6, observe and repeat per protocol
4 interpretation
Probable fetal asphyxia
4 recommended management
Repeat testing same day; if biophysical profile score <6, deliver
0 to 2 interpretation
Almost certain fetal asphyxia
0 to 2 recommended management
Deliver
This abbreviated biophysical profile required approximately ________ to perform, and they
concluded that it was a superb antepartum surveillance method
because there were no unexpected fetal deaths
10 minutes
The American College of Obstetricians and Gynecologists
(2016) has concluded that the ___________
is as predictive of fetal well-being as other approaches to biophysical fetal surveillance
modified biophysical profile test
The importance of _________ is indicated by its inclusion into virtually all schemes in which fetal health is assessed
amnionic fluid volume estimation
_________ measured by Doppler ultrasound reflects
downstream impedance
Blood flow velocity
For growth restricted fetuses, several fetal vascular circuits including the
_________, ________ and __________
have been evaluated as diagnostic tools for fetal well-being.
umbilical artery
middle cerebral artery
ductus venosus
____________ has also been assessed as a modality to predict placental
dysfunction, with the goal to balance stillbirth against the
risks of preterm delivery
Maternal uterine artery Doppler velocimetry
The rationale is that ______
would improve placental blood low in the presence of placental insufficiency. This proved untrue, as ______ was associated
with detrimental efects on fetal cardiovascular dynamics.
sildenafil
Waveforms were first studied in the umbilical arteries late in pregnancy, and abnormal waveforms correlated with _____________.
placental villous
hypovascularity
According to
Trudinger (2007), because more than 40 percent of the combined
fetal ventricular output is directed to the placenta, obliteration of
placental vascular channel increases afterload and leads to fetal
hypoxemia. This in turn leads to ventricular dilation and redistribution of ___________ blood low
middle cerebral artery
Ultimately, pressure
rises in the ductus venosus due to afterload in the ______ side of the
fetal heart.
right
Clinically, abnormal Doppler wave forms in the ductus venosus are a late finding in the progression
of fetal deterioration due to ____________.
chronic hypoxemia
The umbilical artery systolic-diastolic (SID) ratio is considered abnormal if it is _________ for gestational age or
if diastolic flow is either absent or reversed
> 95th percentile
Absent or reversed end- _________ signifies greater impedance to umbilical artery blood flow
diastolic flow
_________ has not proved valuable as a
screening test for fetal compromise in the general obstetrical
population.
velocimetry
Various other fetal-maternal Doppler indices have been
studied, including the :
fetal middle cerebral artery
ductus venosus
the uterine arteries
Still, the technology has received particular attention because of observations that the hypoxic fetus
attempts ________ by reducing cerebrovascular impedance
and thus increasing blood flow.
brain sparing
Middle cerebral artery Doppler velocimetry has proven valuable to detect severe ________ in 165 fetuses with D-antigen
alloimmunization.
fetal anemia
These investigators concluded that ______ could
safely replace amniocentesis in the management of alloimmunized
pregnancies.
Doppler
They concluded that _________ was the best predictor of perinatal outcome.
ductus venosus velocimetry
Also, _________ at delivery was a major determinant of perinatal outcome independent of ductus venosus flow.
gestational age
Specifically, absent or reversed flow in the ductus venosus
was associated with profound generalized ____________.
fetal metabolic collapse
They too reported that gestational age was a powerful
cofactor in ultimate perinatal outcome for growth-restricted
fetuses delivered before ______.
30 weeks
Vascular resistance in the uterine circulation normally decreases
in the first half of pregnancy due to invasion of maternal uterine vessels by ___________.
trophoblastic tissue
This process
can be detected using Doppler flow velocimetry, and ______________ may be most helpful in assessing pregnancies at high risk of utero placental insufficiency
uterine artery Doppler
The risk of fetal death before 32 weeks when associated with: was significantly linked to high-resistance flow.
abruption, preeclampsia, or fetal-growth
restriction
This has led to suggestions for continued research of ____________ as a screening tool to detect pregnancies
at risk for stillbirth.
uterine artery
Doppler velocimetry
a _________________ is highly reassuring that a stillbirth will not occur within 1 week
normal antepartum fetal test result
The most important
consideration in deciding when to begin antepartum testing is
the prognosis for __________.
neonatal survival
The severity of maternal disease is another. In general, with
most high-risk pregnancies, testing begins by _______ weeks’
gestation
32 to 34
Pregnancies with severe complications might require
testing as early as _________ weeks.
26 to 28
he frequency for repeating
tests has been arbitrarily set at ______ but more frequent testing
is often done.
7 days,
