Exam Questions and CORRECT Answers
.Transducer-tipped: Introduced in the 1980s as an alternative to fluid-filled. The force exerted by
a uterine contraction is converted to an electrical signal that is transmitted through a wire system
to a fetal monitor where the uterine activity is displayed graphically on the fetal monitor tracing
Sensor-tipped: Air-coupling technology, which is a newer method of IUPC monitoring, uses a
distally mounted flexible balloon in the uterus connected to an external reusable transducer in the
monitor cable. Similar to noninvasive blood pressure monitors, this catheter consists of a
membrane sensor at the tip of the catheter that communiated pressures through a microcolumn of
air to a transducer located outside the body
What is the paper speed for EFM tracing? - CORRECT ANSWER - Changes in paper
speed can substantially alter the appearance of the tracing. The commonly used paper in the US
has markings on the vertical scale from 30-240 bpm with dividing lines at 10-bpm intervals.
Should be set to 3cm on the horizontal scale (slower than Europe)
What is artifact? - CORRECT ANSWER - Irregular variations or absence of the FHR on
the fetal monitor record resulting from mechanical limitations of the monitor, electrical
interference, or weak signal, appearing as gaps or dots. With FSE, artifact may appear in the
form of irregular lines with varying lengths.
FSE artifact vs arrhythmias: arrhythmias will be regular lines
What is half-counting in regards to the FHR? - CORRECT ANSWER - Most commonly
seen when the FHR is rapid, such as with fetal supraventricular tachycardia
What is double-counting in regards to FHR? - CORRECT ANSWER - May occur during
periods of bradycardia
,What are some troubleshooting interventions for fetal monitoring? - CORRECT
ANSWER - Repositioning the US transducer, ensuring an adequate amount of coupling
gel is used, and checking for proper placement of FSE
Check maternal pulse, encourage maternal position changes, tighten belt as needed, check
connection to the power source as well as connections to the monitor, apply FSE if clinically
indicated
What are some patient education points for fetal monitoring? - CORRECT ANSWER -
Education regarding available and recommended methods of fetal assessment should be
customized for each woman and is essential for women to make fully informed decisions about
their health care. Explain how equipment works. Use intermittent auscultation when able
What are some extrinsic influences on FHR patterns? - CORRECT ANSWER - Maternal
influences
Uteroplacental perfusion
Umbilical circulation
Amniotic fluid characteristics
What are maternal influences on FHR patterns? - CORRECT ANSWER - Oxygenation
status, hemoglobin levels (ability to carry oxygen on each molecule), anything that affects
uterine blood flow (smokers, hypertension, hypotension), maternal cardiac output- will influence
uterine blood flow
What are uteroplacental circulation factors that influence FHR patterns? - CORRECT
ANSWER - Uterine blood flow is dependent on maternal BP. Factors affecting uterine
blood flow include: contractions, hypertonus, hypertension, hypotension, vasocontstriction.
Maternal blood enters the intervillous space in the placenta via spiral arteries... the exchange of
gases and nutrients occur at the chorionic villi.
Placental transfer can be affected by: Placental area (IUGR, abruption), concentration gradients,
diffusing distance, uterine blood flow, umbilical blood flow
,What are the mechanisms of exchange between fetal and maternal blood in the placenta? -
CORRECT ANSWER - Simple diffusion: oxygen, carbon dioxide, many drugs
Facilitated diffusion: glucose, carbs
Active transport: large ions, water-soluble vitamins, amino acids
Bulk flow: water, dissolved electrolytes
Pinocytosis: immune globulins, serum proteins
Breaks and leakage: maternal or fetal blood cells
What are placental changes that affect FHR? - CORRECT ANSWER - Old placenta with
lesions/calcifications may not perfuse as well. Vasoconstriction from HTN can decrease blood
flow to the uterus and placenta. Abruption. Postmaturity (aging placenta). If placenta function is
decreased, the fetus may run out of fetal reserves very quickly. 70-90% of maternal blood
perfusing the uterus passes through the intervillous space
How can umbilical circulation affect FHR? - CORRECT ANSWER - Can be affected by
an abnormal cord, cord compression such as nuchal or true knot, one artery instead of two (two
vessel cord)
How can amniotic fluid affect FHR? - CORRECT ANSWER - Amniotic fluid decreases as
the pregnancy nears term and post term. Amniotic fluid cushions the fetus and cord from
contractions. If volume is decreasing, it fan also indirectly indicate worsening placental
function... as blood is shunted away from kidneys, which decreases fetal output.
Polyhydramnios: 60% idiopathic, but can be associated with multiple gestation, diabetes,
hydrops, chromosomal disorders
Oligohydramnios: (EFI <5cm) associated with IUGR, renal anomalies, pulmonary hypoplasia,
post-term pregnancy and ROM
What are some intrinsic factors that influence FHR patterns? - CORRECT ANSWER -
Fetal circulation, cardioregulatory center, automonic nervous system responses
(parasympathetic, sympathetic), baroreceptors, chemoreceptors, hormonal responses
, How does fetal circulation influence FHR? - CORRECT ANSWER - Opposite in fetus: 1
vein carry oxygenated blood TO the fetus, 2 arteries carry oxygen poor and waste products
BACK to the placenta.
Remember the pneumonic: AVA
Oxygen goes to the most vital organs 1st: Heart and brain.
If there are fetal compensatory mechanisms occuring dt the suboptimal intrauterine environment,
this is where you might see IUGR as the blood flow is shunting away from less vital organs.
Oxygenation occurs in the placenta, not the lungs
These shunts allow preferential streaming to the vital organs and returns deoxygenated blood to
the placenta to be reoxygeneated (There is less blood flow to the lungs as it is not essential at this
time)
How does the cardioregulatory center affect FHR? - CORRECT ANSWER - Located in
the medulla oblongata.
Interacts with the other systems (sympathetic, parasympathetic, baroreceptors) and integrates it
all to control FHR baseline rate, variability
How does the parasympathetic nervous system affect FHR? - CORRECT ANSWER -
Stimulation of the vagus nerve.
Think SLOW, vagal response
Decreases the FHR
Slows the SA node (intrinsic pacemaker) with advancing gestational age, resulting in lower FHR
baseline and increased FHR variability.
Parasympathetic may have a larger role in FHR variability
May be caused by fetal head compression -> early decel, CPD, fetal descent, SVE, repeated
scalp stimulation