#145 Antepartum Fetal Surveillance Flashcards
What is the goal of antepartum fetal surveillance?
Prevent fetal death
Can fetal death from umbilical cord accident be predicted on antepartum fetal surveillance?
No, sudden event, not generally well predicted by tests
True or false, maternal-fetal movement assessment “kick counts” is a method of antepartum fetal surveillance
True
How do you counsel a woman on kick counts?
Multiple protocols.
Option 1: Lie on side, feel belly, perception of 10 distinct movements in a period of up to 2 hours = reassuring
Option 2: Count movements for 1 hour three times per week. Reassuring if equal or exceeded established baseline
Do uterine contractions improve, worsen, or have no effect on fetal oxygenation?
Transiently worsen
What is defined as an adequate contraction stress test?
At least three contractions persist for at least 40 seconds each in a 10-minute period
Do contractions for contraction stress test need to be induced?
No, can use spontaneous contractions if frequent enough
How are contractions induced for a contraction stress test?
Nipple stimulation or IV oxytocin
Which method of inducing contractions for contraction stress test is faster, nipple stimulation or IV oxytocin?
Nipple stimulation, usually takes half the time
What is a negative contraction stress test?
No late or significant variable decelerations
What is a positive contraction stress test?
Late decelerations after 50% or more of contractions
What is an equivocal contraction stress test?
FHR decelerations that occur in the presence of contractions more frequent than every 2 minutes or lasting longer than 90 seconds
What is an equivocal-suspicious contraction stress test?
Intermittent late decelerations or significant variable decelerations
What is an unsatisfactory contraction stress test?
Fewer than three contractions in 10 minutes or an uninterpretable tracing
What is fetal heart rate reactivity thought to be a good indicator of?
Normal fetal autonomic function
What can cause decrease fetal heart rate reactivity?
Fetal sleep cycle, any cause of CNS depression including fetal acidemia
What is the use of vibroacoustic stimulation for NSTs?
Can elicit accelerations. Reduces the frequency on non reactive NSTs by 40%
What percentage of NSTs from normal 24-28wk fetuses are non reactive?
Up to 50%
What percentage of NSTs from normal 28-32wk fetuses are non reactive?
15%
What is the definition of an acceleartion for GA <32 wks
10 x 10
What are the components of a biophysical profile?
NST, breathing, movement, tone, MVP
What is required to score points for breathing on BPP?
One or more episodes of rhythmic fetal breathing of 30 seconds or more within 30 minutes
What is required to score points for movement on BPP?
Three or more discrete body or limb movements within 30 minutes
What is required to score points for tone on BPP?
One or more episodes of extension of a fetal extremity with return to flexion, or opening or closing of a hand
What is required to score points for amniotic fluid volumem on BPP?
A single deepest vertical pocket greater than 2cm
What makes up a modified BPP?
NST and amniotic fluid volume assessment
In which pregnancies are fetal umbilical artery dopplers indicated?
Pregnancies complicated by fetal growth restriction
What is the negative predictive value of an NST for fetal death in the next week?
99.8%
What is the negative predictive value of a BPP for fetal death in next week?
99.9%
Has antepartum fetal surveillance been shown to decrease rik of fetal death?
Lack of high-quality evidence that it decreases risk of fetal death. Most evidenc supporting it is circumstantial and observational
What maternal conditions are indications for antepartum fetal surveillance?
pregestaional DM, HTN, SLE, CKD, APLS, poorly controlled hyperthyroid, hemoglobinopathies, cyanotic heart disease
What pregnancy-related conditions are indications for antepartum fetal surveillance?
gHTN, PEC, decreased fetal movement, GDM (poorly controlled or medicated), oligo, fetal growth restriction, late term/postterm, isoimmunization, previous fetal demise, monochorionic multiple gestation (w/ significant growth discrepency)
How early should you start antepartum fetal testing?
Usually not prior to 32 weeks unless multiple high risk comorbidiites
How often should you perform antepartum fetal testing?
Depends on clinical scenario. Typically once per week
How often should you repeat a growth ultrasound for a growth restricted baby?
Every 3-4 weeks. Not more frequently than every 2 because of inherent error associated with US measurements
What is the next step in management for a pregnant women in DKA with non reassuring antepartum fetal testing?
Correct maternal condition and retest fetus
True or false, antepartum fetal testing has high positive predictive value?
False
What score on a BPP is considered equivocal?
6/10
How do you manage a fetus with a 6/10 BPP at 36 weeks?
Repeat BPP in 24 hours
How do you manage a fetus with a BPP 6/10 at 37 weeks?
Further evaluation, consideration of delivery
What is the next step in management for BPP 4/10? Does recommendation change based on gestational age?
Usually indicates delivery is warranted. For pregnancies less than 32 weeks, management should be individualized and extended monitoring may be appropriate
At what gestational age should you deliver a growth restricted fetus with absent end-diastolic flow, based on SMFM guidelines?
At or beyond 34 weeks
At what gestational age should you deliver a growth restricted fetus with reversed end-diastolic flow, based on SMFM guidelines?
At or beyond 32 weeks
At what gestational age should you deliver a growth restricted fetus with elevated S/D ratio (ie, >95%tile), but diastolic flow still present, based on SMFM guidelines?
At or beyond 37 weeks
Should AFI or MVP be used to drive management decisions? Why?
MVP. Clinical trials indicate that use of MVP (instead of AFI) to diagnose oligohydramnios is associated with a reduction in unnecessary interventions without an increase in adverse perinatal outcomes
When should you consider delivery for a patient with uncomplicated isolated and persistent oligohydramnios?
Delivery at 36-37 weeks
What is the recommendation regarding follow up of amniotic fluid measurements in setting of PPROM?
May often be safely omitted
What is the role of umbilical artery dopplers in a normally grown fetus?
Has not been shown to be predictive of outcomes in fetuses without growth restriction
Is it recommended for women to perform daily fetal movement assessments?
No, has not been shown to reduce fetal death or increase rate of intervention
