1M - Antenatal Fetal Surveillance Flashcards
amount of fetal death before labor?
2/3
This causes inadequate delivery of nutrients or respiratory substances to fetal tissues
Uteroplacental insufficiency
Fetal complications of antepartum asphyxia?
Stillbirth and metabolic acidosis at birth
What are the 4 categories of antenatal testing techniques?
Maternal assessment of fetal activity
Cardiotocographic assessment with or without induced contractions
Sonographic assessment of fetal behavior and/or amniotic fluid volume
doppler velocimetry
What are the extremes of fetal growth?
Fetal growth restriction and fetal macrosomia
Fetal risk factors associated with small for gestational age fetus?
aneuploidy
fetal malformations
multiple gestations
fetal infections: cytomegalovirus, toxoplasmosis, rubella, malaria
What are the placental risk factors for small for gestational age fetus?
Abruption
placenta previa and accreta
chorioangioma
A women with a fundic height of 25 cm in her 26th week of gestation is recommended to be tested for fetal growth restriction. T or F?
False
at 24 weeks, the fundic height should correspond to the age of gestation
a measurement of more than 2-3 cm less is the threshold before recommendation
What is the position of the mother when being examined for fundic height?
Semi recumbent
What are the steps in fundal height measurement?
Semi recumbent position with empty bladder
Determine fundus with 2 hands
Secure tape at top of fundus
Measure fundus using tape along the longitudinal axis
Plot and record
What is the parameter that suggests intarauterine growth restriction during fundic height test?
More than 4 cm difference and less than 10th percentile in size
This is a harbinger or impending fetal death according to Sadovsky?
Diminished fetal heart activity
When does passive unstimulated fetal activity commence?
As early 7 weeks
Beyond 8 weeks, fetal body movements are perceived every?
13 minutes
When does the fetus start to show rest-activity cycles
20-30 weeks
Max activity at 28-32 weeks
Period of active fetal body movements last about how long?
40 minutes
longest period without fetal movement is 75 minutes
What time of the day do fetal movements peak?
9:00 pm to 1:00 am
This stage of fetal behavioral state is the quiescent state (quiet sleep) with narrow oscillatory bandwidth of the fetal heart rate?
Stage 1F
Fetus spend most of their time in stage 1F and 2F
This stage of fetal behavioral state is analogous to rapid eye movement or active sleep phase in neonates.
Stage 2F
This stage includes continuous eye movements without body movements and no accelerations in heart rate.
Stage 3F
One of the vigorous body movement with continuous eye movements and fetal heart rate accelerations. This is the awake state.
Stage 4F
In daily fetal movement count, how many movements can the mother perceive every 30 minutes?
3 movements
In Cardiff Count to 10 method, what time would the mother start counting for fetal movements and for how long?
At 9 am and for 12 hours
How many fetal movements should be present within the 12 hour period in Cardiff Count to 10 method?
10
Based on the Sadovsky Method, how many fetal movements should the mother record while laying for 1 hour?
4 fetal movements
If not felt within the first hour, monitor for a second hour, if still not reached, further evaluation is recommended
This technique is used to monitor fetal heart rate and uterine contractions to monitor fetal well being and detect early fetal distress?
Cardiotocography
Normal fetal heart rate is?
110-160 bpm
Most common explanation for fetal tachycardia?
Chorioamnionitis with fever or any cause of maternal fever
Causes of fetal bradcardia?
Post dated gestation
occiput posterior presentation
transverse presentation
What is the normal variability?
5-25
Variability indicates what?
neurological system state of the fetus to adapt its fetal heart rate response to the environment
What is non reassuring variability?
Less than 5 bpm for between 30-50 minutes
More than 25 bpm for 15-25 minutes
What is abnormal variability?
Less than 5 bpm for more than 50 minutes
More than 25 bpm more than 25 minutes
sinusoidal
What can cause reduced variability?
Fetal sleeping - should not last more than 40 minutes
Fetal acidosis due to hypoxia
fetal tachycardia
drugs
Prematurity - variability is reduced for less than 28 weeks gestation
congenital heart abnormalities
This is defined as an abrupt increase in the baseline
fetal heart rate of greater than 15 bpm for greater
than 15 seconds.
Accelerations
Accelerations are reassuring? T or F?
True
Accelerations coinciding with contractions is a sign of a healthy fetus; and are common during labor
At less than 32 weeks, what is the fetal heart rate acceleration?
more than 10 bpm for >10 secs
at more than 32 weeks, what is the expected fetal heart rate acceleration?
more than 15 bpm for >15 secs
What is prolonged acceleration?
More than 2 mins but less than 10 minutes
Defined as e an abrupt decrease in the baseline
fetal heart rate of greater than 15bpm for greater
than 15 seconds.
deceleration
When do early decelerations happen?
Start when the uterine contraction begins and recover when uterine contraction stops
What is the cause of decelerations?
Increase in intracranial pressure which increases vaginal tone
Early deceleration resolving after uterine contractions end are pathological? T or F?
False, they are physiological
Variable decelerations have a relationship with uterine contractions? T or F
False, no relationship
What is the usual cause of variable deceleration?
Umbilical cord compression
Initially, umbilical vein is compressed causing acceleration and then when the artery is compressed, there is rapid deceleration and when pressure is relieved, another acceleration towards normal occurs
What do we call the acceleration before and after a variable
deceleration which is a sign that the fetus is not yet hypoxic and is adapting to reduced blood flow?
Shoulder of deceleration
This deceleration occurs at the peak of contraction and ends after the contraction ends?
Late deceleration
Late deceleration indicates what situations?
Uteroplacental insufficiency
Insufficient blood flow to uterus and placenta which causes fetal hypoxia and acidosis
Caused by:
maternal hypotension
pre eclampsia
uterine hyperstimulation
Prolonged deceleration lasts for how long?
More than 2 mins but less than 10 mins
Non reassuring prolonged deceleration lasts for?
2-3 mins
abnormal prolonged deceleration lasts for?
> 3 mins
If deceleration lasts for more than 10 minutes, there is a baseline change. What are the causes of prolonged deceleration for more than 10 mins?
Prolonged cord compression prolonged uterine hyperstimulation severe abruptio placenta eclamptic seizure conduction anesthesia
This pattern in cardiotocograph is very concerning as it is associated with high rates of fetal morbidity and mortality. This is characterized by smooth, regular, wavelike patterns with no variability.
Sinusoidal pattern
If a sinusoidal pattern is present, what are the current conditions of the fetus?
severe fetal hypoxia
severe fetal anemia
fetal/maternal hemorrhage
This pattern is characterized by rapid irregular, abrupt up and down fluctuations across the baseline with amplitude of > 25 beats per minute. Zig zag pattern for 1 minute
Saltatory
Saltatory pattern indicates what?
autonomic instability with exaggerated autonomic response
This test measures the fetal heart rate of the fetus in response to its movement?
Non stress test
A reactive non stress test is normal or abnormal?
Normal
If the fetus is normal, as the fetus moves, what happens to the fetal heart rate?
There will be acceleration
Non stress test is done in what position?
Left lateral recumbent position
What is a normal non stress test?
2 or more accelerations 15 or more each lasting 15 secs and occurring within 20 mins of the test
Enumerate the amplitude ranges?
Absent
Minimal - 0 to 5
Moderate - 6-25
Marked - > 25
Contraction stress test measure what?
Uteroplacental function by inducing contraction
If a pathology in uteroplacental blood flow is present, what is seen in cardiotocograph?
Late decelerations
Contraction stress test is deemed positive if?
Late decelerations are present in more than 50% of the induced contractions
What is present in suspicious contraction stress test?
abnormal baseline fetal heart rate and intermittent late, variable decelerations
Unsatisfactory contraction stress test is noted if?
Not enough contractions are elicited. Fewer than 3 contractions per 10 minutes. Or uninterpretable reading
Contraindications to contraction stress test?
Preterm labor
PROM
Hx of extensive surgery or classic CS
placenta previa
What is hyperstimulation in contraction stress test?
Fetal heart rate decelerations that occur in the presence of contractions more frequent than every 2 minutes or lasting longer than 90 secs.
If upon biophysical scoring, an score of 6/8 or 6/10 is achieved, what would be the next step?
reassessment
What test identifies oligohydramnios and polyhydramnio?
amniotic fluid measurement.
Normal value is 2-8 cm
What are additional tests added to the modified biophysical scoring test?
AFI and fetal non stress test
What are normal values for NST and AFI for modified biophysical scoring test?
AFI of >5 cm and a reactive NST
When do we consider an umbilical doppler velocimetry abnormal?
If there is absent diastolic flow and when flow index is 2 points greater than SD for gestational age (95th percentile for gestational age)
In the presence of fetal hypoxia, what happens to middle cerebral artery impedance?
it decreases to increase blood flow to the middle cerebral artery to facilitate brain sparing
This test is an indirect
measure of uterine artery vascular resistance
uterine artery velocimetry
As gestation advances in normal pregnancy, what happens to the uterine vascular resistance?
It decreases.
What drug is given at 16 weeks of gestation in women who are at risk for fetal growth restriction due to elevated uterine artery resistance?
Aspirin
What are abnormal findings on doppler uterine artery velocimetry?
bilateral uterine notches and pulsatility index > 1.45 in both arteries
Testing uterine artery velocimetry is appropriate at what age of gestation for those at risk of stillbirht?
32-34 weeks
In pregnancies with
multiple or particularly worrisome high-risk conditions, testing may be initiated as early as?
26-28 weeks
a vertical pocket of amniotic fluid greater than 2 cm or amniotic fluid index of 5 cm or less is defined as?
Oligohydramnios
