COMPLETE QUESTIONS AND ANSWERS
◉ Oligohydramnios. Answer: 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. Answer: US transducer, depicts valve closure; uses
autocorrelation
◉ Autocorrelation. Answer: successive US waveforms at many
points; current technology which is more accurate at detecting FHR
variability; controls artifact sound waves
◉ Toco/tocotransducer. Answer: 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. Answer: R-R waves; still has
issues with artifact; risk of injury, measuring maternal HR in
instance of fetal demise; rupture and dilation required
,◉ IUPC. Answer: solid>fluid filled tips, measures mmHg and allows
amnioinfusion; issue with displacement, perforation, placental
abruption
◉ Intermittent auscultation. Answer: 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. Answer: q15 min for high risk up to
q30min
◉ Second stage auscultation. Answer: q5 min if high risk up to
q15min
◉ Fetal tolerance of labor. Answer: auscultate after a contraction x
30-60 seconds; document rate, rhythm, accels, decels
◉ Doppler vs. fetoscope. Answer: doppler uses autocorrelation and
detects valve closure; fetoscope listens through opening in heart
wall?
◉ Signal ambiguity. Answer: 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. Answer: when there is lower baseline or
>50% contractions with accelerations (especially with pushing);
verify and document maternal heart rate via pulse oximetry
◉ Halving/doubling. Answer: Halving occurs if FHR >180-200; may
double if rate <50
◉ Extrinsic factors. Answer: 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. Answer: the maternal
respiratory system
◉ Uterine blood flow. Answer: 60ml/min non-pregnant vs. 500-
1000ml/min; 10-15% maternal cardiac output
◉ Normal blood flow pathway. Answer: Blood from maternal vein >
intervillous pool of maternal blood > umbilical vein (oxygenated
blood)
◉ Normal placenta. Answer: 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. Answer: fetal asphyxia
◉ Chronic drop in placental function. Answer: FGR
◉ O2 and CO2. Answer: simple transport (diffusion); electrolytes, fat
soluble vitamins, narcotics, anesthetic gasses, antibiotics
◉ Glucose. Answer: facilitated transport, by carrier molecules
◉ Active. Answer: amino acids, calcium, iron, water soluble vitamins
(uses ATP)
◉ Umbilical blood flow. Answer: 2 arteries (deoxygenated) and 1
vein (oxygenation)
◉ Fetal circulation. Answer: when compromised, fetal blood
redistributed to heart, brain, adrenals; shunting and FHR increase
compensate for decreased blood flow and hypoxemia; limit mixing
of oxygenated and deoxygenated blood