NST and other labor tests Flashcards
normal fetal HR
normal 110 - 160 / min
antepartum fetal surveillance - tests
- nonstress test
- biophysical profile
- contraction stress test
- Doppler sonography of the umbilical artery
nonstress test - description
reactive: 2 or more accelerations
abnormal: less than 2 accelerations or recurrent, variable or late decelerations
Normal labor - accelerations
normal acceleratipns are an increase in HR of 15 or more beats per minute above the baseline for longer than 15-20 sec. If this happens twice in 20 mins, it is REASSURING or normal
non reactive NST –> (next step)
vibroacoustic (maybe due to sleeping) –> if still nonreactive –>
Byophisical profile or contraction stress test
(no contraction if contraindication of labor like placenta previa or prior myomectomy)
biophysical profile - description
nonstress test plus U/S assessment of: - amniotic fluid volume: - fetal breathing - fetal movement - fetal tone (2 points per catergory)
biophysical profile - normal vs abnormal
normal: 8-10 points
abnormal: 0-4 points, oligohydramnios
equivocal: 6 points
6/10 biophysical test - next step
do it again in 24 hours
contraction stress test - description
external fetal HR monitoring during spontaneous or induced (eg. oxytocin, nipple stimulation) uterine contraction
contraction stress test - normal vs abnormal
normal: no late or recurrent variable declarations
abnormal: late decelerations with more than 50% of contractions
Doppler sonography of the umbilical artery - description
evaluation of umbilical artery flow in fetal intrauterine growth restriction only
Doppler sonography of the umbilical artery - normal vs abnormal
normal: high velocity diastolic flow in umibilical artery
abnormal: decreased, absent, or reserved end diastolic flow
biophysical profile: details of every parameter
- NST
- single fluid pocket 2cm or more x 1 cm or amniotic fluid index more than 5%
- fetal movements: 3 or more general body movements
- fetal tone: 1 or more episode of flexion/extension of limbs or spine
- fetal breathing: 1 or more breathing episodes for 30 or more sec
decreased or absent fetal contraction –> next step
doppler
fetal HR?
YES –> NST
NO –> Transabdominal u/s
normal labor - deceleration (types)
- early
- variable
- late (most serious and dangerous)
normal labor - early deceleration (description and cause)
- decrease in HR that occurs with contractions
- nadir of deceleration corresponds to peak of contraction
- gradual (30 or more sec from onset to nadir)
- head compression / can be normal fetal tracing
normal labor - variable deceleration (description and cause)
- decrease in HR and return to baseline with no relationship with contraction
- abrupt (less than 3- sec from onset to nadir
- decrease 15 or more / min, duration 15 or more sec but less than 2 min
- umbilical cord compression or prolapse or oligohydramnios
normal labor - late deceleration (description and cause)
- decrease in HR after contraction started. NO RETURN TO BASELINE UNTIL CONTRACTION ENDS
- nadir of deceleration occurs after peak of contraction
gradual (30 or more sec from onset to nadir - fetal hypoxia (eg. uteroplacental insuf)
normal labor - cause of every type
- early –> head compression
- variable –> umbilical cord compression / prolapse / oligohydramnios
- late –> fetal hypoxia
how to reduce cord compression
maternal repositioning –> if fails –> amnioinfusion
amnoinfusion
instillation of saline into uterine cavity for treatment of reccurentvariable decelerations due to umbiilical cord compression during labor
uterine rupture - NST
late deceleration
