Fetal Biophysical Profile

Question 1

FETAL BIOPHYSICAL PROFILE

Answer 1

 Antepartum fetal surveillance is the assessment of fetal well-being in utero before the onset of labor
 It is a technique employed to forecast fetal well-being by focusing on fetal biophysical findings that include heart
rate, movement, breathing, and amniotic fluid production

Question 2

what are the parameters of a fetal biophysical profile?

Answer 2

It contains 5 parameters;
1. Nonstress test (NST),
2. Fetal breathing,
3. Fetal movements,
4. Muscle tone and
5. Amniotic fluid volume

Question 3

Modified Biophysical Profile

Answer 3

Modified Biophysical Profile consists of NST and ultrasonographically determined amniotic fluid index (AFI)
and is considered abnormal (non reassuring) when the NST is non-reactive and/or the AFI is < 5
 Combines NST and Amniotic fluid index
 Takes only 10 minutes to perform
 It is reactive if the NST is reactive and AFI is more than 5.it is then repeated once a week or earler if
clinicaly required
 It is abnormal if AFI is less or NST is non reactive. Then a BPP is done

Question 4

Aim of biophysical profile

Answer 4

 Early detection of fetus at risk so that timely management to prevent further deterioration
 Also find out normal fetuses and avoid unnecessary interventions
NB: Has a very high negative predictive value and very low positive predictive value

Question 5

Indication of fetal surveillance (BPP)

Answer 5

 Maternal conditions
a) Hypertension
a) Diabetes mellitus
b) Heart Disease
c) Chronic renal disease
d) Acute febrile illness
e) Pneumonia /asthma
f) Epilepsy
g) Collagen vascular disease
h) Sickle cell disease
i) Antiphospholipid syndrome
j) Drug Abuse

 Fetal conditions
a) Fetal growth restriction
b) Rh isoimmunisation
c) Fetal Cardiac arrhythmia
d) Hydrops fetalis
e) Fetal infections

Pregnancy related conditions
a) Preeclampsia
b) Multiple pregnancy
c) Post term pregnancy
d) Decreased fetal movements
e) Abnormal placentation
f) Placental abruption
g) Oligohydramnios
h) Polyhydramnios
i)
Unexplained stillbirth in a previous pregnancy
Cholestasis of pregnancy
k)
PROM
1)
Poorly controlled Gestational Diabetes mellitus

Question 6

what is non stress test?

Answer 6

Non stress test
 Involve use of Doppler-detected FHR acceleration coinciding with fetal movements perceived by the mother
 It describes FHR acceleration in response to fetal movement as a sign of fetal health
 This reactivity denotes CNS activity
 Its absence depicts hypoxia (as hypoxia develops, FHR accelerations diminish), drugs, fetal sleep, congenital
anomalies
 Observed for 20 minutes but extended to 40 min if there are no accelerations in 20 minutes
 A 40-minute or longer tracing to account for fetal sleep cycles should be performed before concluding that there
was insufficient fetal reactivity
 Also accelerations with or without fetal movements may be accepted

Question 6

other (not BPP) Methods of Antepartum Fetal Surveillance

Answer 6

The Various Methods of Antepartum Fetal Surveillance
1) Clinical assessment by uterine growth
2) Fetal movement count by the mother
3) Ultrasound for fetal growth
4) Non stress test and cardiotocography
5) Vibroacoustic stimulation test
6) Contraction stress test
7) Nipple stimulation test
8) Biophysical profile
9) Modified biophysical profile
10) Doppler studies
11) Fetal lung maturation studies
12) Placental grading

Question 7

 Reactive NST

Answer 7

 Baseline fetal heart rate between 110 to 160 bpm
 Baseline variability > 5 bpm
 Two or more accelerations of 15 bpm lasting 15 seconds in 20 minutes period
 No decelerations
 NST shd be done after 28 weeks as it is nonreative in 50% cases before that
 It is a screeing test with false positive rate of 50% and false negative rate of .3%

Question 8

Abnormal results of NST

Answer 8

Abnormal results;
 Baseline oscillation of less than 5 bpm,
 Absent accelerations, and
 Late decelerations with spontaneous uterine contractions
 Abnormal results are consistently associated with evidence of uteroplacental pathology eg; IUGR, placental
infarction, Oligohydramnios, fetal academia and meconium
 Interval between testing, set at 7 days; but more frequent testing is advocated for women with post-term
pregnancy, multifetal gestation, type 1 diabetes mellitus, IUGR, or gestational hypertension
 In these circumstances, twice-weekly tests, with additional testing is advised

Question 9

outline the fetal behavioral states that might be seen when assesing fetal movement

Answer 9

 Four fetal behavioral states are described:
 State 1F is a quiescent state; quiet sleep, with a narrow oscillatory bandwidth of the FHR
 State 2F includes frequent gross body movements, continuous eye movements, and wider oscillation of
FHR. It is analogous to REM or active sleep in the neonate
 State 3F includes continuous eye movements in absence of body movements and no heart rate accelerations
 State 4F is one of vigorous body movement with continuous eye movements and heart rate accelerations.
This state corresponds to the awake state in newborns

Question 10

Fetal movements

Answer 10

 Passive unstimulated fetal activity commences as early as 7 weeks’ gestation and becomes more sophisticated
and coordinated by the end of pregnancy
 Between 20 and 30 weeks, general body movements become organized, and by 36 weeks behavioral states are
established in most normal fetuses
 Fetuses spend most of their time in states 1F and 2F (>75% at 38 weeks)
 Mean length of the quiet or inactive state for term fetuses was 23 minutes (up to 75min)
 Amnionic fluid volume is another important determinant of fetal activity
 Perception of 10 fetal movements in up to 2 hours is considered normal

Question 11

Fetal breathing

Answer 11

 Two types of respiratory movements;
 First are gasps or sighs, which occurred at a frequency of 1 to 4 per minute
 Second, irregular bursts of breathing, occurred at rates up to 240 cycles per minute
 These latter rapid respiratory movements are associated with REM sleep
 Diurnal variation, because breathing substantively diminishes during the night
 But, increases somewhat following maternal meals
 Total absence of breathing would be observed in some normal fetuses for up to 122 minutes, indicating fetal
evaluation to diagnose absent respiratory motion may require long periods of careful observation

Question 12

Amniotic fluid volume

Answer 12

 Decreased uteroplacental perfusion may lead to diminished fetal renal blood flow, decreased urine production,
and ultimately, Oligohydramnios
 Amniotic fluid index < 5 cm or a maximum deepest vertical pocket < 2 cm are acceptable criteria for diagnosis
of Oligohydramnios
 Normal; ≥ 1 pocket measuring 2 cm in two perpendicular planes (2 × 2 cm pocket)

Question 13

Fetal muscle tone

Answer 13

 Normal; ≥ 1 episode of extension (limb or trunk) with return of flexion

Question 14

Contraction stress test

Answer 14

 Formerly known as oxytocin challenge test
 Oxytocin infusion is given till there are 3 contractions in 10 minutes and the FHR response was recorded
 Fetal oxygenation is transiently worsened by uterine contraction
 To see the fetal response to uterine contractions
 Rarely done now days
 Criterion for a positive test result, that is, an abnormal result, is to have uniform repetitive late fetal heart
rate decelerations (which could be the result of uteroplacental insufficiency)
 Negative-no late or variable decelerations
 Positive-late deceleration in > 50% of the contractions

Question 15

Contraction stress test indication and contraindication

Answer 15

 Indication is nonreactive non stress test
 Contraindicated in;
a) Patient with risk of preterm labour
b) PROM
c) H/O uterine surgery, classical caesarean section
d) Known placenta previa, multiple gestation, cervical incompetence, vasa previa

Question 16

Nipple stimulation test

Answer 16

 Induces uterine contractions is usually successful in conducting contraction stress testing
 2-minute nipple stimulation ideally will induce a pattern of 3 contractions per 10 minutes, if not after 5 minutes,
retry, if unsuccessful, diluted oxytocin

Question 17

Acoustic stimulation test

Answer 17

 Loud external sounds have been used to startle the fetus and thereby provoke heart rate acceleration
 An acoustic stimulator is positioned on the maternal abdomen, and a stimulus of 1 to 2 seconds is applied
 A positive response is defined as the rapid appearance of a qualifying acceleration following stimulation

Question 18

Doppler blood flow velocity / Doppler velocimetry

Answer 18

 Arterial Doppler waveforms are helpful to assess the downstream vascular resistance
 Maternal uterine artery Doppler velocimetry has also been evaluated to predict placental dysfunction or
placental insufficiency
 The changes in vascular resistance is more marked in uterine artery closer to placental implantation site.
 Diastolic notching is an index of increased impedance to flow.
 Abnormal uterine arteries waveforms after 24 wks of gestation are associated with development of
preeclampsia, abruption, FGR, morbidity & mortality
 Venous Doppler parameter provide information about cardiac forward function (cardiac compliance, contractility
and after load)
 Fetuses with abnormal cardiac function show pulsatile flow in the umbilical vein (UV)
 Normal UV flow is monophasic

Question 19

what fetal vascular circuits are assesed in Doppler blood flow velocity / Doppler velocimetry

Answer 19

 Three fetal vascular circuits;
a) Umbilical artery- assessed in fetal growth restriction, preeclampsia, DM, reduced fetal movement
b) Middle cerebral artery- assessed in fetal growth restriction and Rh isoimmunisation
c) Ductus venosus- assessed in fetal growth restriction
 All can be assessed to determine fetal health