ASSESSMENT OF
Fetal
Well-being
Lectures 3
Assessment of fetal well-being
• The major expected outcome is the detection of
potential fetal compromise
• Used before intrauterine asphyxia of the fetus and
health care provider can take measures to prevent or
minimize adverse perinatal outcomes
• First- and second-trimester antepartal assessment is
directed primarily at the diagnosis of fetal anomalies.
• The goal of third-trimester testing is to determine
whether the intrauterine environment continues to be
supportive to the fetus.
Daily Fetal
Movement
Counts
Daily Fetal Movement Counts
Kick Counts
– Assessment of fetal activity by the mother
– Non-invasive, inexpensive, simple to understand, and
does not interfere with routine at home
– once a day, roughly at the same time every day in a
comfortable sitting or lying position
– when baby is usually active (after meals, after activity,
and in the evening).
– Since healthy babies have sleep cycles, baby may not
kick, or kick less than usual, or have less than 10 kicks in
2 hours. If so, wake up the baby by drinking fluid or by
walking for 5 minutes. Repeat the kick count.
Daily Fetal Movement Counts Kick Counts
–No less than3 movements in 30 minutes
–Most healthy babies should take less than 2 hours for 10 kicks.
–not moved 10 times in 2 hours or the baby has sustained significant
changes.
–Fetal alarm signal if no movement in 12 hours
–The evaluation may include:
–Ultrasound - taking pictures from sound waves to evaluate the growth of the baby,
amniotic fluid quantity, placenta, blood flow pattern etc.
–Non stress test (NST) -Baby's heart rate monitoring in response to its own
movements
–Biophysical profile (BPP) -using an ultrasound exam with a non stress test (NST)
to evaluate baby's heart rate, breathing, body movement, muscle tone, and amniotic
fluid quantity
–Contraction stress test (CST) -Baby's heart rate monitoring in response to uterine
contractions
OBSTETRIC
ULTRASOUND
• Ultrasound in obstetrics can provide good
information about the fetus and its environment
• With ultrasound, can be determined an early
intervention or conservative management in
pregnancy
• Latest developments in ultrasound examination
is a transvaginal ultrasound discovery - the
observation of "FLOW DOPLLER" and the
most sophisticated ultrasound 3 D and 4D which
has a high ability to determine fetal condition
7
Ultrasonography
• Indications for use
–
–
–
–
–
–
–
–
Fetal heart rate activity
Gestational age
Fetal growth
Fetal anatomy
Fetal genetic disorders and physical anomalies
Placental position and function
visual assistance to other invasive tests
Fetal well-being
Ultrasonography
Abdominal
• After 1 trimester
• Full blader
Vaginal
•
•
•
•
1 trimester
Early diagnostic of uterine pregnancy
Empty blader
Obese woman
Ultrasonography
An important and safe technique in antepartum fetal
surveillance
Levels of ultrasonography:
• Standard examination
– Used for specific indications, i.e., fetal viability, fetal presentation,
gestational age, locate the placenta, fetal anatomy and malformation
• Specialized or targeted examination
– Suspicion of an abnormal fetus (abnormal finding on clinical
examination, poly- or oligohydramnionios, elevated AFP)
Ultrasonography: Indication for use 1
trimester
• Number, size, location of gestational sac
• Fetal cardiac and body movement
• Uterine abnormalities (bicornuate uterus, uterine
fibroid, IUD) or adnexal masses
• Duration of pregnancy (crown-rump length)
• Visualization during chorionic villus sampling
Ultrasonography: Indication for use
( 2nd and 3rd trimester )
1. Fetal viability, number and presentation,
2. Establishment of fetal age and growth by fetal biometry including:
a.
b.
c.
d.
BPD ~ biparietal diameter
FL ~ femur length
AC ~ Abdominal circumference
Biophysical profile
a.
b.
c.
d.
e.
f.
Cerebral lateral ventricles
Spine
Four chamber view of the heart
Stomach-bowel, abdominal wall at the area of the umbilical cord insertion
Bladder and kidney
Limbs and umbilical cord
3. Evaluation of fetal anatomic structures:
4.
5.
6.
7.
8.
Amount of amniotic fluid
Placental localization and maturity
Evaluation of the uterine, and adnexae for abnormalities and masses
Cervical length
Visual assistance to invasive tests
12
Fetal heart activity
• 6-7 weeks by echo scaner
• 10-12 weeks by Doopler
Fetal viability
• Fetal cardiac activity
• Fetal movement
• Breathing movement
Gestational age
•
•
•
•
Gestational sac dimensions (about 8 weeks)
Crown-rump length (7-12 weeks)
Biparietal diameter (after 12 weeks)
Femur length (after 12 weeks)
• BPD, FL and AC the most important parameters for
determination of gestational age
• Determination of gestational age should be performed
prior to 26 weeks gestational age
• 3rd trimester determination of gestational age does not
acurately reflect gestational age
Fetal growth
• BPD ~ biparietal diameter
• FL ~ femur length
• AC ~ Abdominal circumference
• Discrepancy resulting from inaccurate dates
– True intrauterine growth restriction (IUGR)
•
•
Symmetric - the fetus being small in all parameters, reflects a chronic or longstanding insult and may be caused by low genetic growth potential, intrauterine
infection, undernutrition, heavy smoking, or chromosomal aberration.
Asymmetric - head and body growth varying, suggests an acute or late-occurring
deprivation, such as placental insufficiency resulting from hypertension, renal
disease, or cardiovascular disease.
– Macrosomia - weighing more than 4000 g, associated with maternal glucose
intolerance, carries an increased risk of intrauterine fetal death, and at increased
risk for trauma during birth.
Ultrasonography: gestational age
Week’s Gestation
7 – 10
Crown-rump length
(CRL)
10 - 14
Crown-rump length
Biparietal Diameter
(BPD)
Femur Length (FL)
Humerus Length (HL)
15 - 28
Biparietal Diameter
Femur Length
Humerus Length
Head Circumference
(HC)
Binocular distance
29
Femur Length
Humerus Length
Binocular distance
Biparietal Diameter
Other long bones
Head Circumference
a In decreasing order
b Only if cephalic index ( BPD divided by occipital-frontal diameter ) is
normal ( 76-84%) ; otherwise , the fetal head may be
dolichocephalic or brachycephalic
16
1st trimester fetus CRL
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28 mm CRL in 10 weeks
twin pregnancy
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Biparietal Diameter
a cross section through the fetal head at the level of the thalamus.
The skull is represented by the thick white lines which surround the
brain. This view is used to measure the biparietal diameter (line) and
the circumference of the head (dots).
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Fetal Femur
20
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Pregnant uterus - longitudinal
21
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Fetal : intracranial structure and extremity
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Fetal anatomy
•
•
•
•
•
Head (ventricles, blood vessels)
Neck
Spine
Heart
Stomach
•
•
•
•
•
Small bowel
Liver
Kidney
Blader
Limb
Fetal Cardiac
Structure
24
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Fetal Liver and
Lung interface
25
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Fetal Liver
3rd Trimester 26
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Fetal Spine
27
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Spine
3D
28
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Neural tube defects
• NTD’s result from failure of tube closure by
the 6th weeks gestational age (embryonic age 26
– 28 days )
• Various NTD’s anomalies :
– Anencephaly
– Encephalocele
– Spina Bifida
29
Gross malformation may be detected in 1st
trimester sonogram 1:
• Anencephalus (absence of a major portion of
the brain, skull, and scalp)
• Acrania (partial or complete absence of the
cranium).
30
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Spina Bifida
• Consist of a hiatus, usually in the lumbosacral
vertebrae, through which a meningeal sac may
protruded → meningocele
• 90% of cases, the sac contains neural elements →
meningomyelocele
• The fetal spine should be examined by sonography
with: sagittal, tranverse and coronal views
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Spina
Bifida
33
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NEURAL TUBE DEFECTS
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NEURAL TUBE DEFECTS
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Fetal anatomy
Gross malformation may be detected in 1st
trimester sonogram 2:
• Hydrancephaly (the cerebral hemispheres are
absent and replaced by sacs filled with
cerebrospinal fluid
• Cystic Hygroma (is a congenital multiloculated
lymphatic lesion that can arise anywhere, but is
classically found in the left posterior triangle of
the neck.
36
Abdominal Wall Defects
• The two most common are :
– Omphalocele
– Gastroschisis
• Can be ascertained early in pregnancy by maternal
serum alphafetoprotein screening programs
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Gross malformation may be detected in 1st
trimester sonogram 3:
• Omphalocele (abdominal wall defect in which
the intestines, liver, and occasionally other
organs remain outside of the abdomen in a
sac)
• Gastroschisis (paraomphalocele congenital
abdominal wall defect in which the intestines
and sometimes other organs develop outside
the fetal abdomen through an opening in the
abdominal wall)
38
OMPHALOCELE
GASTROSCHISIS
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Duodenal atresia
• Diagnosed prenatally by the demonstration of the
double bubble sign ( distension of the stomach and first
part of the duodenum )
• Must be differentiated from other cystic structures in
the upper abdomen
• Diagnosis generally is not possible before 24 weeks
• 30% of cases has been associated with trisomy 21
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Gross malformation may be detected in 1st
trimester sonogram 4:
• Fused twins (Siamese twins) are identical
twins whose bodies are joined in utero
42
Fetal genetic Disorders
Nuchal Translucency
• The maximum thickness of the subcutaneus
translucent area between the skin and the soft tissues
overlying the posterior aspect of the cervical spine in
sagital scane plane. (10-14 weeks)
• A thickness > 3 mm ( sagital plane):
– 90% trisomy 18 and 13
– 80% trisomy 21
– 5% normal
43
Placenta position and function
• Location
• Relationship between cervical os
• Maturation
Uterus and Adnexa
• Cervical incompetence :
– Tunneling of the internal ( dilatation )
– Cervical length < 3 cm
– Bulging membranes
( with or without prolaps of the cord or fetal
parts )
• 30 weeks of gestational age: length of
cervix more than 3 cm
• Adnexal mass :
– Physiological: Diameter corpus luteum at
pregnancy about 2 cm
• Uterine fibroid
45
Sonographic assesment of the
amniotic fluid
• Normal : at 2nd and 3rd trimester vertical
pocket about 2 cm
• AFI ( amniotic fluid index ): sum of the depth
of the largest pocket of fluid in the four
quadrants of abdomen
• AFI < 5 cm : strongly asociated with
oligohidramnions postmaturity
46
Amniotic Fluid
47
Index 3/14/2016
Interpretation of the AFl
10.1 to 24.0 cm
Normal
5.1 to 10.0 cm
Borderline
Less than or equal 5.0 cm Abnormal (Oligohydramnios)
Greater than 24.0 cm
Abnormal (Polyhydramnios)
Oligohydramnios is associated with congenital abnomalies
(ex. renal agenesis) growth restriction fetal distress
Polyhydramnios is associated with neural tube defects
obstruction of the fetal gastrointestinal tract, multiple fetuses
and fetal hydrops
DOPPLER VELOCIMETRY
• The primary use of Doppler echo shifts in obstetrics have been
to detect and measured blood flow
• Basis of Doppler Velocimetry : The sound of moving blood
cells within vasculature generates an effective Doppler Shift
• There are 2 methods of estimating circulatory hemodynamics :
– Direct measurement of the volume of blood flow
– Indirect estimation of flow velocity using wave form
analysis
49
DOPPLER VELOCIMETRY
• The shifted frequencies can be displayed as a
plot of velocity versus time, and the shape of
these waveform can be analyzed to give
information about blood flow and resistance in
a given circulation
• Velocity waveforms from umbilical and uterine
arteries, reported as systolic/diastolic (S/D)
ratio achieve
DOPPLER VELOCIMETRY
• Most fetuses will achieve an S/D ratios of 3 or
less by 30 weeks
• Persistent elevation of S/D ratios after 30
weeks is associated with IUGR resulting from
uteroplacental insuficiency
• In postterm pregnancies an elevated S/D ratio
indicates a poorly perfused placenta
• Abnormal result are seen with chromosome
abnomalities in the fetus
51
Fetal Umbilical Cord Doppler
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DOPPLER VELOCIMETRY
Fetal Breathing Movement
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Fetal Umbilical artery
and Bladder
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Biophysical profile (BPP)
•
•
•
Real-time ultrasound permits detailed assessment of the physical and physiologic
characteristics of the developing fetus and cataloging of normal and abnormal
biophysical responses to stimuli.
The biophysical profile (BPP) is a noninvasive dynamic assessment of a fetus and its
environment by ultrasonography and external fetal monitoring. BPP scoring is a
method of fetal risk surveillance based on the assessment of both acute and chronic
markers of nonreassuring fetal status.
The BPP includes:
–
–
–
–
–
•
fetal breathing movements,
fetal movements,
fetal tone,
fetal heart rate patterns by means of a nonstress test,
AFV;
The fetal response to central hypoxia is alteration in movement, muscle tone,
breathing, and heart rate patterns. The presence of normal fetal biophysical activities
indicates that the central nervous system (CNS) is functional and the fetus therefore is
not hypoxemic
Biophysical profile (BPP)
Biophysical profile (BPP)
• The BPP is an accurate indicator of impending fetal death.
• Fetal acidosis can be diagnosed early with a nonreactive
nonstress test and absent fetal breathing movements.
• An abnormal BPP score and oligohydramnios are indications
that labor should be induced.
• Fetal infection in women whose membranes rupture prematurely
(at less than 37 weeks of gestation) can be diagnosed early by
changes in biophysical activity that precede the clinical signs of
infection and indicate the necessity for immediate birth.
• When the BPP score is normal and the risk of fetal death low,
intervention is indicated only for obstetric or maternal factors.
Magnetic
resonance
imaging
Magnetic resonance imaging (MRI)
• Noninvasive radiologic technique
• Like CT provides pictures of soft tissue
• Unlike CT is not use ionizing radiation
Magnetic resonance imaging (MRI)
– Fetal structure
– Placenta (position, density, and presence of
gestational trophoblastic disease)
– Quantity of amniotic fluid
– Maternal structures (uterus, cervix, adnexa,
and pelvis)
– Biochemical status of tissues and organs
– Soft tissue, metabolic, or functional anomalies
BIOCHEMICAL
ASSESSMENT
BIOCHEMICAL ASSESSMENT
• Involves biological examination and chemical
determination
• Procedures used to obtain needed speciment
–
–
–
–
Amniocentesis
Percutaneous umbilical blood sampling
Chorionic villus sampling
Maternal sampling
BIOCHEMICAL
ASSESSMENT.
Amniocentesis
Amniocentesis
• First introduced by Serr and Fuchs and
Riis in the 1950s for fetal sex
determination
• Only at the late 70th a static ultrasound
was used to locate the placenta and
amniotic fluid pocket
• Only In 1983, Jeanty reported a
technique of amniocentesis ’’under
ultrasound vision’’
Amniocentesis is perform to obtain amniotic fluid, which contains
fetal cells. Under direct ultrasonographic visualization, a needle is
inserted transabdominally into the uterus, amniotic fluid is withdraw
into a syringe, and the various assessment are performed
•
Amniocentesis: Indications
Genetic disorders
– women more than 35 years old, with a previous child with a
chromosomal abnormality, or with a family history of
chromosomal anomalies.
– Inherited errors of metabolism (such as Tay-Sachs disease,
hemophilia, and thalassemia) and other disorders for which
marker genes are known may also be detected.
– Cells are cultured for karyotyping of chromosomes.
Karyotyping also permits determination of fetal sex, which is
important if a sexlmked disorder is suspected.
– Alpha-fetoprotein (AFP) levels are assessed as a followup for
elevated levels in maternal serum. High AFP levels in amniotic
fluid help confirm the diagnosis of a neural tube defect such as
spina bifida or anencephaly or an abdominal wall defect such
as omphalocele. AFP levels may also be elevated in a normal
multifetal pregnancy and with intestinal atresia, presumably
caused by lack of fetal swallowing.
•
Assessment of pulmonary maturity
– L/S > 2:1
•
Diagnosis of fetal hemolytic disesase
– bilirubin level < 0.015
Amniocentesis
• After 10-14 weeks gestation
– Early – earlier than 15 weeks
– Late – second trimester after 15 weeks
• Only the amniotic (inner) sac should be
aspirated
• Approximately 1 cc for gestational age
• laboratory failure op to 20%
Complications
• Leakage of amniotic fluid (better prognosis than
spontaneous leakage)
• Amnionitis
• Vaginal bleeding
• Needle puncture of the fetus
• Long term complications:
– Respiratory distress??
– Isoimmunization??
Amniocentesis
• Maternal complications • Fetal complications
– Hemorrhage
– Fetomaternal hemorrhage
with possible maternal Rh
isoimmunization
– Infection
– Labor
– Abruptio placentae
– Damage to intestines or
bladder
– Amniotic fluid embolism
–
–
–
–
Death
Hemorrhage
Infection (amnionitis)
Direct injury from the
needle
– Miscarriage or preterm
labor
– Leakage of amniotic
fluid
Amniocentesis and HIV positive women
• Increased rate of vertical transmission
• Chemoprophylaxis previous to amniocentesis
appears to be beneficial in preventing vertical
transmission
Multiple Gestation
• Three methods:
– Indigo carmine injection to the first sac
– A single needle puncture sampling technique (Jeanty
1990)
– Simultaneous visualization of two needles on each
side of the separating membrane (Bahado-Singh 1992)
– Abortion risk – probably higher
– Detailed description of fetus
position and placental location
BIOCHEMICAL
ASSESSMENT
Percutaneous umbilical blood
sampling (CORDOCENTESIS)
CORDOCENTESIS
Involves the insertion of the
needle directly into fetal umbilical
vessel under ultrasound guidance
and the removing 1-4 ml of
blood
CORDOCENTESIS
•
•
•
•
•
Indications for use
Prenatal diagnosis of inherited blood disorders
Karyotyping of malformed fetuses
Detection of fetal infection
Determination of the acid-base status of fetuses
with IUGR
Assessment and treatment of isoimmunization
and trombocytopenia in the fetus
CORDOCENTESIS.
Complications
•
•
•
•
•
•
Blood leaking from puncture site
Cord laceration
Thromboembolism
Preterm labour
Premature rupture of membranes
Infections
BIOCHEMICAL
ASSESSMENT
Chorionic villus sampling
Chorionic villus sampling (CVS)
– Earlier diagnosis and rapid results
– Performed between 10 and 12 weeks of gestation
– Removal of small tissue specimen from fetal
portion of placenta
• Chorionic villi originate in zygote and reflects genetic
makeup of fetus
Chorionic villus sampling
•
•
•
•
Was developed in the 80th
percutaneous transabdominal
transvaginal
transcervical
Chorionic villus sampling (CVS)
• Complications:
–
–
–
–
vaginal spotting or bleeding immediately afterward,
Miscarriage
Rupture of membranes,
chorioamnionitis.
• Because of the possibility of fetomaternal
hemorrhage, women who are Rh negative
should receive immune globulin (RhoGAM) to
avoid isoimmunization.
Chemical
determination
SERUM MARKER
• Serum marker
– maternal serum alphafetoprotein MS-AFP
– maternal unconjugated estriol
– maternal serum beta-human chorionic
gonadotropin (hCG)
– Others
• Pregnancy associated plasma protein - A
(PAPP-A)
• Inhibin A
SERUM MARKER
• Positive test indicates increased risk
• Negative test indicates no increased risk but not
mean normal fetus
• Multiple fetuses cannot be assessed
AFP
• AFP is produced by the fetal liver, and increasing levels
are detectable in the serum of pregnant women from
14 to 34 weeks.
• Approximately 80% to 85% of all open NTDs and
open abdominal wall defects
• Screening is recommended for all pregnant women.
• If findings are abnormal, follow-up procedures include
genetic counseling for families with a history of NTD,
repeat AFP, ultrasound examination, and possibly
amniocentesis.
Triple screening
(16-18 weeks)
• Maternal serum alpha-fetoprotein (MS-AFP)
• Human chorionic gonadotropin (hCG)
• Unconjugated estriol (UE3)
Quadruple Screen
(15-22 weeks most accurate 16-18 weeks)
•
•
•
•
AFP
hCG
UE3
Inhibin
Quadruple Screen
hCG
Estradiol
Inhibin
AFP
Down Syndrome
High
Low
High
Low
Neural or
abdominal wall
defects
Trisomy 18
Nml
Nml
Nml
High
Low
Low
Low
Low
Down Syndrome
PAPP-A is low
Inhibin A is elevated
Electronic fetal
monitoring
Indications for Electronic Fetal Monitoring
Assessment Using NST and CST
• Maternal diabetes mellitus
• Chronic hypertension
• Hypertensive disorders in
pregnancy
• IUGR
• Sickle cell disease
• Maternal cyanotic heart
disease
• Postmaturity
• History of previous
stillbirth
• Decreased fetal movement
• Isoimmunization
• Meconium-stained amniotic
fluid at third-trimester
amniocentesis
• Hyperthyroidism
• Collagen disease
• Older pregnant woman
• Chronic renal disease
Contraindications for Electronic Fetal
Monitoring Assessment
• NST
– No
– but results may not be conclusive if
• gestation is 26 weeks or less.
• CST :
–
–
–
–
–
rupture of membranes,
previous classic incision for cesarean birth,
preterm labor,
placenta previa,
placenta abruptio
–
–
–
–
–
multifetal pregnancy,
previous preterm labor,
hydramnios,
more than 36 weeks of gestation,
incompetent cervix
Fetal Responses to Hypoxia or Asphyxia
• Hypoxia or asphyxia elicits a number of responses in the fetus.
There is a redistribution of blood flow to certain vital organs.
This series of responses (redistribution of blood flow favoring
vital organs, decrease in total oxygen consumption, and switch to
anaerobic glycolysis) is a temporary mechanism that enables the
fetus to survive up to 30 minutes of limited oxygen supply
without decompensation of vital organs.
• However, during more severe asphyxia or sustained hypoxemia,
these compensatory responses are no longer maintained, and a
decrease in the cardiac output, arterial blood pressure, and blood
flow to the brain and heart occurs, with characteristic FHR
patterns reflecting these changes.
Fetal heart rate terminology
• Baseline rate
-110-160
Bradycardia&Tachicardia
• Variability
-Longterm & Short term
• Acceleration
• Deceleration
-Early
-Late
Varible
NST
• is the most widely applied technique for antepartum evaluation
of the fetus.
• Basis: the normal fetus will produce characteristic heart rate
patterns in response to fetal movement.
• can be performed easily in an outpatient setting because it is
noninvasive.
• relatively inexpensive and has no known contraindications.
• Disadvantages center around the high rate of false-positive
results for nonreactivity as a result of fetal sleep cycles,
medications, and fetal immaturity.
• The test is also slightly less sensitive in detecting fetal
compromise than are the CST and BPP.
NST Interpretation
• Two or more accelerations of 15 beats per minute
lasting for 15 seconds over a 20-minute period
• Normal baseline rate
• Long-term variability amplitude of 10 or more beats
per minute
• If the test does not meet the criteria after 40 minutes, it
is considered nonreactive, in which case further
assessments are needed with a CST or BPP.
• twice weekly (after 28 weeks of gestation) with patients
who are diabetic or at risk for fetal death.
• Reactive
NST
– 2 or more accelerations of FHR of 15 beats/min lasting ≥15 sec,
associated with each fetal movement in 20-min period
– Allow to continue
• Nonreactive
– Any tracing with either no FHR accelerations or accelerations <15
beats/min or lasting <15 sec throught any fetal movement during testing
period
– CST, BBP
• Unsatisfectory quality of FHR recording not adequate for
interpretation
– Repeated in 24 hours or
– CST
CST
• Uterine contractions decrease uterine blood flow and
placental perfusion. If this decrease is sufficient to
produce hypoxia in the fetus, a deceleration in FHR will
result, beginning at the peak of the contraction and
persisting after its conclusion (late deceleration).
– Nipple-Stimulated
• 10 min massage
• 2 min massage 5 min break
– Oxitocin-Stimulated
• 10 U in 1000 ml fluid IV
•
NEGATIVE
CST
– No late decelerations, with minimum of three uterine contractions lasting 40 to 60 sec within 10min period
• Reassurance that the fetus is likely to survive labor should it occur within 1 wk; more frequent testing
may be indicated by clinical situation
•
POSITIVE
– Persistent and consistent late decelerations occurring with more than half of contractions
• Management lies between use of other tools of fetal assessment such as BPP and termination of
pregnancy; a positive test result indicates that fetus is at increased risk for perinatal morbidity and
mortality; physician may perform expeditious vaginal birth after successful induction or may proceed
directly to cesarean birth; decision to intervene is determined by fetal monitoring and presence of FHR
reactivity
•
SUSPICIOUS
– Late decelerations occurring in less than half of uterine contractions once adequate contraction
pattern established
• NST and CST should be repeated within 24 hr; if interpretable data cannot be achieved, other methods
of fetal assessment must be used*
•
HYPERSTIMULATION
– Late decelerations occurring with excessive uterine activity (contractions more often than every 2
min or lasting longer than 90 sec) or persistent increase in uterine tone
•
UNSATISFACTORY
– Inadequate uterine contraction pattern or tracing too poor
CST
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