Relias - Fetal Heart Monitoring questions and
answers 2025
uterine blood supply - - ANS--- uterine arteries deliver oxygenated blood to spiral
arteries which bring oxygen rich blood to intervillous space of placenta that has fetal
capillaries
- fetal capillaries carry the O2 rich blood to umbilical VEIN that goes to fetus
-in contrast, the umbilical ARTERIES return waste products to that intervillous space
that go into mother's venous system
Potential issues that negatively affect fetal oxygenation - - ANS--*Maternal
Oxygenation:* asthma, hyper- or hypo- ventilation
*Maternal Circulation:* decreased maternal cardiac output, hypotension, decreased Hgb
*Placental O2 and CO2 Exchange:* postterm, abruption, HTN, hypotension, uterine
tachysystole
*Fetal circulation:* cord compression or occlusion
Fetal hypoxemia - - ANS--- can occur d/t reduced fetal O2 reserves, excessive uterine
activity, or reduced uteroplacental blood flow
- worsening fetal hypoxemia can lead to abnormal FHR patterns, mostly minimal or
absent variability from acidemia
(1) hypoxemia vs. (2) hypoxia - - ANS--1 - reduce O2 in blood
2 - reduced O2 delivery at tissue level
Fetal anaerobic metabolism - - ANS--- occurs when long term O2 delivery is insufficient
to meet cellular needs of tissues
- results in production of lactic acid and other noncarbonic acids
- ACIDOSIS is the presence of excessive acids in tissues
acidosis - - ANS--pH below 7.35
pH is low
(acidosis is the process that leads to low blood pH, or acidemia)
, alkalosis - - ANS--pH above 7.45
pH is high
buffers - - ANS--- help maintain acid base homeostasis
- 2 major fetal buffers are plasma bicarbonate and hgb
base excess and base deficit - - ANS--- base deficit is expressed as a positive number
- base excess is expressed as a negative number
~ they are equivalent and terms are used interchangeably ~
fetal acidosis - - ANS--- when O2 is decreased to fetus, tissue hypoxia results in
acidosis, which then shows a drop in pH, a loss of bicarb, and increase in base deficit
acidemia - - ANS--assoc w/ widespread, deleterious effects on vital organ and body
function
fetal hypoxia during birth - - ANS--assoc w/ neonatal depression, low apgars, neonatal
encephalopathy, and cerebral palsy
respiratory acidosis - - ANS--*low pH (< 7.10), high pCO2 (> 60), normal base deficit ( <
12)*
- increase of pCO2 for fetus that lowers pH but doesn't affect base deficit
factors that contribute to resp acidosis - - ANS--- sudden decrease in placental or cord
perfusion
- uterine tachysystole
- maternal hypoventilation
metabolic acidosis - - ANS--*ph < 7.10 , normal pCO2 (<60), high base deficit (>12)*
- a higher base deficit (such as > 12) has been assoc w/higher risk for severe neonatal
complications
- most common cause of metabolic acidosis in fetus is r/t inadequate O2 delivery
- prolonged hypoxic insult to fetus results in depletion of bicarb, which is a base buffer
that normalizes pH levels
mixed acidosis - - ANS--*pH < 7.10 , high pCO2 > 60, and high base deficit >12*
answers 2025
uterine blood supply - - ANS--- uterine arteries deliver oxygenated blood to spiral
arteries which bring oxygen rich blood to intervillous space of placenta that has fetal
capillaries
- fetal capillaries carry the O2 rich blood to umbilical VEIN that goes to fetus
-in contrast, the umbilical ARTERIES return waste products to that intervillous space
that go into mother's venous system
Potential issues that negatively affect fetal oxygenation - - ANS--*Maternal
Oxygenation:* asthma, hyper- or hypo- ventilation
*Maternal Circulation:* decreased maternal cardiac output, hypotension, decreased Hgb
*Placental O2 and CO2 Exchange:* postterm, abruption, HTN, hypotension, uterine
tachysystole
*Fetal circulation:* cord compression or occlusion
Fetal hypoxemia - - ANS--- can occur d/t reduced fetal O2 reserves, excessive uterine
activity, or reduced uteroplacental blood flow
- worsening fetal hypoxemia can lead to abnormal FHR patterns, mostly minimal or
absent variability from acidemia
(1) hypoxemia vs. (2) hypoxia - - ANS--1 - reduce O2 in blood
2 - reduced O2 delivery at tissue level
Fetal anaerobic metabolism - - ANS--- occurs when long term O2 delivery is insufficient
to meet cellular needs of tissues
- results in production of lactic acid and other noncarbonic acids
- ACIDOSIS is the presence of excessive acids in tissues
acidosis - - ANS--pH below 7.35
pH is low
(acidosis is the process that leads to low blood pH, or acidemia)
, alkalosis - - ANS--pH above 7.45
pH is high
buffers - - ANS--- help maintain acid base homeostasis
- 2 major fetal buffers are plasma bicarbonate and hgb
base excess and base deficit - - ANS--- base deficit is expressed as a positive number
- base excess is expressed as a negative number
~ they are equivalent and terms are used interchangeably ~
fetal acidosis - - ANS--- when O2 is decreased to fetus, tissue hypoxia results in
acidosis, which then shows a drop in pH, a loss of bicarb, and increase in base deficit
acidemia - - ANS--assoc w/ widespread, deleterious effects on vital organ and body
function
fetal hypoxia during birth - - ANS--assoc w/ neonatal depression, low apgars, neonatal
encephalopathy, and cerebral palsy
respiratory acidosis - - ANS--*low pH (< 7.10), high pCO2 (> 60), normal base deficit ( <
12)*
- increase of pCO2 for fetus that lowers pH but doesn't affect base deficit
factors that contribute to resp acidosis - - ANS--- sudden decrease in placental or cord
perfusion
- uterine tachysystole
- maternal hypoventilation
metabolic acidosis - - ANS--*ph < 7.10 , normal pCO2 (<60), high base deficit (>12)*
- a higher base deficit (such as > 12) has been assoc w/higher risk for severe neonatal
complications
- most common cause of metabolic acidosis in fetus is r/t inadequate O2 delivery
- prolonged hypoxic insult to fetus results in depletion of bicarb, which is a base buffer
that normalizes pH levels
mixed acidosis - - ANS--*pH < 7.10 , high pCO2 > 60, and high base deficit >12*
