CEFM Exam Questions and Verified Answers Graded A+ 2026/27
EFM is used to... - assess the adequacy of fetal oxygenation with dual aims of:
(1) *confirming normal oxygenation* so that labor can be continued safely
(2) *preventing fetal injury* that may result from interruption of normal fetal oxygenation during
labor
True or false: continuous EFM during labor has been associated with higher cesarean rates as
opposed to IA in healthy low-risk women - • True
• There is no definitive evidence that use of intrapartum EFM leads to significant reduction in
neonatal neurologic morbidity
Physiological pathway of fetal oxygenation -
Oxygen pathway: external environment - *PO2* (partial pressure of oxygen) *declines as
it moves* from environment *to fetus*
Oxygen pathway: maternal lungs - • Carries oxygenated *air from external environment
into alveoli*
• From alveoli, oxygen *diffuses* across thin barrier *into pulmonary capillary blood*
• *Interruption* of O2 transfer *from environment to alveoli can result from airway obstruction
or CNS depression* (ex: asthma, aspiration, apnea, narcotics, magnesium)
,• *Interruptions* of O2 transfer *from alveoli to pulmonary capillary blood can be caused by
ventilation-perfusion mismatch, pulmonary embolism, pneumonia, asthma, atelectasis, or adult
respiratory distress syndrome*
Oxygen pathway: maternal blood - • After *diffusing from pulmonary alveoli* into
maternal blood, approx *98% of O2 combines w Hbg in maternal RBCs* (remaining 2%
dissolves into blood)
• *Amnt of O2 bound to Hgb depends directly on PO2* as illustrated by the oxyhemoglobin
dissociation curve
Oxyhemoglobin dissociation curve - • Relationship between hemoglobin saturation and
Po2
• In general, *tendency for Hgb to release O2 is increased by factors that reflect an increased
need for oxygen* (cellular metabolism)
Oxygen pathway: maternal heart - • Maternal pulmonary *veins carry oxygenated blood
to the heart* and pumped *through aorta for systemic distribution*
• Dependent on normal cardiac function, reflected by cardiac output (HR x SV)
• *Interruption* of O2 to fetus can be caused by *arrhythmias, hypovolemia, compression of
inferior vena cava, impaired contractility (heart dz, diabetes, cardiomyopathy, CHF, HTN), and
structural abnormalities*
• *Most common in OB = hypovolemia*, compression of inferior vena cava by gravid uterus
,Oxygen pathway: maternal vasculature - Aorta → common & internal iliac arteries →
anterior division of internal iliac artery → uterine artery → arcuate arteries → radial arteries →
spiral arteries → enter intervillous space of placenta
• *Interruption* can occur w/ *hypotn* following regional anesthesia, hypovolemia, impaired
venous return, impaired cardiac output, or meds
• *Interruption* can occur w/ *vasoconstriction* in response to endogenous vasoconstrictors or
medications
• *Conditions associated with chronic vasculopathy* - CHTN, long-standing diabetes, collagen
vascular dz, thyroid dz, and renal dz
• *Pre-e* associated w abnormal vascular remodeling and can impede perfusion
• Transient hypotension most common
Oxygen pathway: uterus - • Arcuate, radial, and spiral arteries traverse muscular wall of
uterus
• *Interruption* of O2 transfer commonly *from ctx that compress maternal blood flow in/out of
intervillous space of placenta* - excessive uterine activity, uterine stimulants (prostaglandins,
oxytocin)
Oxygen pathway: placenta - • Facilitates *exchange of gases, nutrients, wastes, and other
molecules* between maternal blood in the intervillous space and fetal blood in the villous
capillaries
• O2 *interruptions - abruption, vasa previa, fetomaternal hemorrhage, placental infarction,
placental infection*
, Maternal side vs fetal side of placenta - • *Maternal side* - O2 exits spiral arteries enters
intervillous space and surround chorionic villi
• *Fetal side* - paired umbilical arteries carry blood from fetus through the umbilical cord to the
placenta
At term, umbilical artery receives ____% of fetal cardiac output - 40%
Intervillous space - • The *space in the placenta* in which maternal blood bathes
chorionic villi, allowing the *exchange of materials between the fetal and maternal circulations*
• *O2 released from maternal Hgb, diffuses* across blood-blood barrier, *binds to fetal Hgb*
• Approx PaO2 45
• *Interruption occurs* when *maternal blood PaO2 is reduced*
At term, uterine perfusion accounts for ____% of maternal cardiac output - 10-20%
Oxygen pathway: umbilical cord - • *After O2 combines w fetal Hgb* in villous
capillaries, *oxygenated blood is transferred to fetus via placental veins* that unite to form a
*single umbilical vein* within the umbilical cord
• Oxygenation most commonly *interrupted by mechanical compression*, also *prolapse* or
*true knot*
Hypoxemia - • *Decreased oxygen in the blood*
EFM is used to... - assess the adequacy of fetal oxygenation with dual aims of:
(1) *confirming normal oxygenation* so that labor can be continued safely
(2) *preventing fetal injury* that may result from interruption of normal fetal oxygenation during
labor
True or false: continuous EFM during labor has been associated with higher cesarean rates as
opposed to IA in healthy low-risk women - • True
• There is no definitive evidence that use of intrapartum EFM leads to significant reduction in
neonatal neurologic morbidity
Physiological pathway of fetal oxygenation -
Oxygen pathway: external environment - *PO2* (partial pressure of oxygen) *declines as
it moves* from environment *to fetus*
Oxygen pathway: maternal lungs - • Carries oxygenated *air from external environment
into alveoli*
• From alveoli, oxygen *diffuses* across thin barrier *into pulmonary capillary blood*
• *Interruption* of O2 transfer *from environment to alveoli can result from airway obstruction
or CNS depression* (ex: asthma, aspiration, apnea, narcotics, magnesium)
,• *Interruptions* of O2 transfer *from alveoli to pulmonary capillary blood can be caused by
ventilation-perfusion mismatch, pulmonary embolism, pneumonia, asthma, atelectasis, or adult
respiratory distress syndrome*
Oxygen pathway: maternal blood - • After *diffusing from pulmonary alveoli* into
maternal blood, approx *98% of O2 combines w Hbg in maternal RBCs* (remaining 2%
dissolves into blood)
• *Amnt of O2 bound to Hgb depends directly on PO2* as illustrated by the oxyhemoglobin
dissociation curve
Oxyhemoglobin dissociation curve - • Relationship between hemoglobin saturation and
Po2
• In general, *tendency for Hgb to release O2 is increased by factors that reflect an increased
need for oxygen* (cellular metabolism)
Oxygen pathway: maternal heart - • Maternal pulmonary *veins carry oxygenated blood
to the heart* and pumped *through aorta for systemic distribution*
• Dependent on normal cardiac function, reflected by cardiac output (HR x SV)
• *Interruption* of O2 to fetus can be caused by *arrhythmias, hypovolemia, compression of
inferior vena cava, impaired contractility (heart dz, diabetes, cardiomyopathy, CHF, HTN), and
structural abnormalities*
• *Most common in OB = hypovolemia*, compression of inferior vena cava by gravid uterus
,Oxygen pathway: maternal vasculature - Aorta → common & internal iliac arteries →
anterior division of internal iliac artery → uterine artery → arcuate arteries → radial arteries →
spiral arteries → enter intervillous space of placenta
• *Interruption* can occur w/ *hypotn* following regional anesthesia, hypovolemia, impaired
venous return, impaired cardiac output, or meds
• *Interruption* can occur w/ *vasoconstriction* in response to endogenous vasoconstrictors or
medications
• *Conditions associated with chronic vasculopathy* - CHTN, long-standing diabetes, collagen
vascular dz, thyroid dz, and renal dz
• *Pre-e* associated w abnormal vascular remodeling and can impede perfusion
• Transient hypotension most common
Oxygen pathway: uterus - • Arcuate, radial, and spiral arteries traverse muscular wall of
uterus
• *Interruption* of O2 transfer commonly *from ctx that compress maternal blood flow in/out of
intervillous space of placenta* - excessive uterine activity, uterine stimulants (prostaglandins,
oxytocin)
Oxygen pathway: placenta - • Facilitates *exchange of gases, nutrients, wastes, and other
molecules* between maternal blood in the intervillous space and fetal blood in the villous
capillaries
• O2 *interruptions - abruption, vasa previa, fetomaternal hemorrhage, placental infarction,
placental infection*
, Maternal side vs fetal side of placenta - • *Maternal side* - O2 exits spiral arteries enters
intervillous space and surround chorionic villi
• *Fetal side* - paired umbilical arteries carry blood from fetus through the umbilical cord to the
placenta
At term, umbilical artery receives ____% of fetal cardiac output - 40%
Intervillous space - • The *space in the placenta* in which maternal blood bathes
chorionic villi, allowing the *exchange of materials between the fetal and maternal circulations*
• *O2 released from maternal Hgb, diffuses* across blood-blood barrier, *binds to fetal Hgb*
• Approx PaO2 45
• *Interruption occurs* when *maternal blood PaO2 is reduced*
At term, uterine perfusion accounts for ____% of maternal cardiac output - 10-20%
Oxygen pathway: umbilical cord - • *After O2 combines w fetal Hgb* in villous
capillaries, *oxygenated blood is transferred to fetus via placental veins* that unite to form a
*single umbilical vein* within the umbilical cord
• Oxygenation most commonly *interrupted by mechanical compression*, also *prolapse* or
*true knot*
Hypoxemia - • *Decreased oxygen in the blood*
