NCC EFM EXAM QUESTIONS AND VERIFIED ANSWERS
Polyhydramnios
single MVP > 8 cm or AFI >24; 1% of pregnancies; 60% idiopathic; multiple gestation,
maternal diabetes, hydrops, anomalies, TORCH; ass'd with cardiac/GI issues/renal
issues
Oligohydramnios
single MVP < 2 cm or AFI < 5 at term (less than 5%ile); associated with FGR, placental
abnormalities, urinary tract abnormalities, post-term pregnancies, ruptured or idiopathic
membranes
Doppler
US transducer, depicts valve closure; uses autocorrelation
Autocorrelation
successive US waveforms at many points; current technology which is more accurate at
detecting FHR variability; controls artifact sound waves
Toco/tocotransducer
detects change in contour with contractions; place at fundus or at area of maximum
palpation; difficult to measure with obesity, polyhydramnios
Fetal scalp electrode measures
R-R waves; still has issues with artifact; risk of injury, measuring maternal HR in
instance of fetal demise; rupture and dilation required
IUPC
solid>fluid filled tips, measures mmHg and allows amnioinfusion; issue with
displacement, perforation, placental abruption
Intermittent auscultation
goal is baseline 110-160, +/-accels, no decels; if present, put on continuous monitor min
20 minutes); cannot determine variability or types of FHR decels
Active phase auscultation
q15 min for high risk up to q30min
Second stage auscultation
q5 min if high risk up to q15min
Fetal tolerance of labor
, auscultate after a contraction x 30-60 seconds; document rate, rhythm, accels, decels
Doppler vs. fetoscope
doppler uses autocorrelation and detects valve closure; fetoscope listens through
opening in heart wall?
Signal ambiguity
confusing maternal and fetal heart rate; common with repositioning, fetal movement,
during pushing (maternal tachycardia); can occur even with fetal demise due to FSE
recording maternal blood flow through the placenta
Suspect signal ambiguity
when there is lower baseline or >50% contractions with accelerations (especially with
pushing); verify and document maternal heart rate via pulse oximetry
Halving/doubling
Halving occurs if FHR >180-200; may double if rate <50
Extrinsic factors
maternal oxygenation, uterine blood flow, placenta exchange, umbilical blood flow;
intrinsic factors = fetal circulation, oxygenation of tissues, FHR regulation
Primary source of oxygen for the feus
the maternal respiratory system
Uterine blood flow
60ml/min non-pregnant vs. 500-1000ml/min; 10-15% maternal cardiac output
Normal blood flow pathway
Blood from maternal vein > intervillous pool of maternal blood > umbilical vein
(oxygenated blood)
Normal placenta
Placenta has 15-20 lobules on maternal surface; Decreased surface area of chorionic
villi from abnormal development, infection, thrombosis, hemorrhage, inflammation
(chorio increases risk of CP), degenerative changes with increasing gestational age
(calcifications)/HTN/DM - can cause IUGR, hypoxia, FHR decels
Acute drop in placental function
fetal asphyxia
Chronic drop in placental function
Polyhydramnios
single MVP > 8 cm or AFI >24; 1% of pregnancies; 60% idiopathic; multiple gestation,
maternal diabetes, hydrops, anomalies, TORCH; ass'd with cardiac/GI issues/renal
issues
Oligohydramnios
single MVP < 2 cm or AFI < 5 at term (less than 5%ile); associated with FGR, placental
abnormalities, urinary tract abnormalities, post-term pregnancies, ruptured or idiopathic
membranes
Doppler
US transducer, depicts valve closure; uses autocorrelation
Autocorrelation
successive US waveforms at many points; current technology which is more accurate at
detecting FHR variability; controls artifact sound waves
Toco/tocotransducer
detects change in contour with contractions; place at fundus or at area of maximum
palpation; difficult to measure with obesity, polyhydramnios
Fetal scalp electrode measures
R-R waves; still has issues with artifact; risk of injury, measuring maternal HR in
instance of fetal demise; rupture and dilation required
IUPC
solid>fluid filled tips, measures mmHg and allows amnioinfusion; issue with
displacement, perforation, placental abruption
Intermittent auscultation
goal is baseline 110-160, +/-accels, no decels; if present, put on continuous monitor min
20 minutes); cannot determine variability or types of FHR decels
Active phase auscultation
q15 min for high risk up to q30min
Second stage auscultation
q5 min if high risk up to q15min
Fetal tolerance of labor
, auscultate after a contraction x 30-60 seconds; document rate, rhythm, accels, decels
Doppler vs. fetoscope
doppler uses autocorrelation and detects valve closure; fetoscope listens through
opening in heart wall?
Signal ambiguity
confusing maternal and fetal heart rate; common with repositioning, fetal movement,
during pushing (maternal tachycardia); can occur even with fetal demise due to FSE
recording maternal blood flow through the placenta
Suspect signal ambiguity
when there is lower baseline or >50% contractions with accelerations (especially with
pushing); verify and document maternal heart rate via pulse oximetry
Halving/doubling
Halving occurs if FHR >180-200; may double if rate <50
Extrinsic factors
maternal oxygenation, uterine blood flow, placenta exchange, umbilical blood flow;
intrinsic factors = fetal circulation, oxygenation of tissues, FHR regulation
Primary source of oxygen for the feus
the maternal respiratory system
Uterine blood flow
60ml/min non-pregnant vs. 500-1000ml/min; 10-15% maternal cardiac output
Normal blood flow pathway
Blood from maternal vein > intervillous pool of maternal blood > umbilical vein
(oxygenated blood)
Normal placenta
Placenta has 15-20 lobules on maternal surface; Decreased surface area of chorionic
villi from abnormal development, infection, thrombosis, hemorrhage, inflammation
(chorio increases risk of CP), degenerative changes with increasing gestational age
(calcifications)/HTN/DM - can cause IUGR, hypoxia, FHR decels
Acute drop in placental function
fetal asphyxia
Chronic drop in placental function
