Fetal Biophysical ProfileFetal Biophysical Profile

in in

high risk pregnancy high risk pregnancy

Presented by: Presented by:

Dr. S. RouholaminDr. S. Rouholamin

Hypoxia : Low Oxygen tensionHypoxia : Low Oxygen tension

Asphyxia : Low Oxygen and high CO2Asphyxia : Low Oxygen and high CO2

Ischemia : Drop in blood flowIschemia : Drop in blood flow

Prediction of the effect of an asphyxial Prediction of the effect of an asphyxial insult on the fetus requires a measure of : insult on the fetus requires a measure of : SeveritySeverity of the asphyxia. of the asphyxia. Duration Duration of the asphyxia.of the asphyxia.

18-48 hrs(Neuronal necrosis) 18-48 hrs(Neuronal necrosis)

48-72hrs(apper. of white 48-72hrs(apper. of white

matter macroph. &Astrocy.). matter macroph. &Astrocy.).

>4days cavitation >4days cavitation

visible on head U/Svisible on head U/S

commentcomment

Fetal asphyxia may or may not be concomitant Fetal asphyxia may or may not be concomitant

with clinical presentation. (based on with clinical presentation. (based on

severity ,duration & location of insult)severity ,duration & location of insult)

ComponentComponentFetal movementsFetal movements 3 body or limb movements3 body or limb movements

Fetal toneFetal tone One episode of active extension and One episode of active extension and flexion of the limbs; opening and flexion of the limbs; opening and closing of handclosing of hand

Fetal breathing Fetal breathing movementmovement

episode of >= 30 seconds in 30 episode of >= 30 seconds in 30 minutesminutes Hiccups are considered Hiccups are considered breathing activity.breathing activity.

Amniotic fluid volumeAmniotic fluid volume single 2 cm x 2 cm pocket is single 2 cm x 2 cm pocket is considered adequate.considered adequate.

Non-stress testNon-stress test 2 accelerations > 15 beats per 2 accelerations > 15 beats per minuteminute of at least 15 seconds duration.of at least 15 seconds duration.

DefinitionDefinition

Fetal movement and fetal tone develop Fetal movement and fetal tone develop

between 7.5 and 9 weeks’ menstrual age between 7.5 and 9 weeks’ menstrual age

Fetal breathing movements are Fetal breathing movements are

detectable by, at least 17-18 weeks’ detectable by, at least 17-18 weeks’

gestationgestation

The biophysical profile score is The biophysical profile score is

continued for a maximum of 30 minutescontinued for a maximum of 30 minutes

Oligohydramnios is now defined as a Oligohydramnios is now defined as a

pocket of amniotic fluid < 2.0 x 2.0 cm pocket of amniotic fluid < 2.0 x 2.0 cm

(Manning, 1995A)(Manning, 1995A)

The Biophysical Profile (BPP)

•Between 24 and 28 weeks' gestation, approximately 50 percent of NSTs are nonreactive.

•In contrast sonographically evaluated variables are valid early in gestation and account for three of the five components of the biophysical profile.

•The biophysical profile may be used to verify fetal well being when the nonstress test is not reactive.

The Biophysical Profile (BPP)

•Fetal movement and fetal tone develop between 7.5 and 9 weeks’ menstrual age.

•Fetal breathing movements are detectable by, at least 17-18 weeks’ gestation.

•Amniotic fluid may be reduced as early as 17.5 weeks by fetal acidosis.

•The components of the biophysical profile develop sequentially. In order of appearance: tone, movement, breathing, reactivity.

The Biophysical Profile (BPP)

•Fetal state (wake-sleep cycle) plays an important role in the interpretation of the biophysical profile score.

•In quiet sleep the average time to obtain a normal biophysical profile score is 26.3 minutes.

•The biophysical profile score is, therefore, continued for a maximum of 30 minutes.

The Biophysical Profile (BPP)

•The sonographic variables that develop last in gestation are the most sensitive to acidosis and would be the first components of the BPP to become abnormal.

•The NST, breathing, and amniotic fluid volume are the most significant variables.

The Biophysical Profile (BPP)

•The non-stress test and fetal breathing movements are suppressed when the pH falls below 7.2.

•If the fetal pH falls below 7.10 fetal tone and fetal movements become abolished

•The presence of oligohydramnios with all of the other variables of the biophysical profile being normal may reflect chronic uteroplacental insufficiency

Components of the Biophysical Profile Score

Component Definition

Non-stress test

Two or more fetal heart rate accelerations peak (but do notnecessarily remain) at least 15 beats per minute above thebaseline and last 15 seconds from baseline to baseline withina 20-minute period with or without fetal movement discernibleby the woman.

Amniotic fluid volume

A single 2 cm x 2 cm pocket is considered adequate or AFIgreater than 5.0 cm .

Fetal breathing movements

One or more episodes of rhythmic fetal breathing movementsof 30 seconds or more within 30 minutes.Hiccups are considered breathing activity.

Fetal movementsAt least three discrete body or limb movements. Episodes of continuous movement are considered as a singlemovement.

Fetal toneOne or more episodes of extension of a fetal extremity ortrunk with return to flexion, or opening or closing of a hand

Perinatal Mortality and the Biophysical Profile Score

Score Interpretation Perinatal Mortality/1000

8- 10 Normal 1.86*

6 Equivocal 9.76

4 Abnormal 26.3

2 Abnormal 94.0

0 Abnormal 285.7

*The perinatal mortality is 0.8/1000 for structurally normal fetuses with a normal test within 7 days.

Maternal and Fetal Causes of Stillbirth within One Week of a Normal Biophysical Profile Score

Maternal Fetal

Placental abruptionDiabetic ketoacidosis Sickle cell crisis Drug overdose Motor vehicle accident Acute myocardial infarction

Acute alcohol poisoning

Fetomaternal hemorrhage

Cord prolapse Ruptured membranes Vase previa Cord entanglement Umbilical artery thrombosis

Factors Affecting the Biophysical ProfileFactors Affecting the Biophysical Profile

Interpretation of an Equivocal or Abnormal BPP

The absence of a biophysical variable may reflect:

•Normal fetal activity and sleep cycles•An inability of the central nervous system to perform that function•Hypoxia •External influences•Fetal breathing movements may be

•Stimulated by caffeine and hyperglycemia.•Inhibited by hypoglycemia, maternal supine hypotension, cigarette smoking, alcohol, diazepam and meperidine.

Action for Equivocal or Abnormal BPP

• The term fetus is generally delivered for a score of 6. • However, a score of 6 in a preterm fetus is usually repeated in 12 to 24 hours. In the interim, antenatal steroids may be given for pregnancies of less than 34 weeks of gestation.

• Delivery is usually indicated for BPP score of 4 or less.

• Oligohydramnios always requires further evaluation.

Patients with a biophysical profile score of 6 or less should be considered for transfer to Labor and Delivery for further observation or delivery and

physician notified.

Special Considerations

Rupture of the membranes does not alter the short-Rupture of the membranes does not alter the short-term sonographic variables of the biophysical profile term sonographic variables of the biophysical profile in the healthy fetus. in the healthy fetus.

The negative predictive value of a normal The negative predictive value of a normal biophysical profile score is not as high with an biophysical profile score is not as high with an anomalous fetus, in contrast to a structurally normal anomalous fetus, in contrast to a structurally normal fetus. fetus.

Sudden fetal deaths have been reported following a Sudden fetal deaths have been reported following a normal biophysical profile score in fetuses with normal biophysical profile score in fetuses with gastroschisis, omphalocele, and diaphragmatic gastroschisis, omphalocele, and diaphragmatic hernia. hernia.

Special Considerations

The observation of an abnormal biophysical The observation of an abnormal biophysical profile in an anomalous fetus does not correlate profile in an anomalous fetus does not correlate very well with the presence of hypoxia.very well with the presence of hypoxia.

The biophysical profile score cannot be used The biophysical profile score cannot be used in fetuses with congenital muscular diseases or in fetuses with congenital muscular diseases or central nervous system conditions that would central nervous system conditions that would affect muscular function. affect muscular function.

If an anomalous fetus had a previously If an anomalous fetus had a previously normal biophysical profile score, a decreasing normal biophysical profile score, a decreasing score should be considered an indication of score should be considered an indication of compromise compromise

Fetal breathing movements. Video shows a rhythmic Fetal breathing movements. Video shows a rhythmic deflection of the fetal chest wall and diaphragm that is clearly deflection of the fetal chest wall and diaphragm that is clearly distinct from the rhythmic motion of the fetal heart. Note that distinct from the rhythmic motion of the fetal heart. Note that the image begins in the transverse view, but the ultrasound the image begins in the transverse view, but the ultrasound transducer is then rotated to show a sagittal view and, finally, transducer is then rotated to show a sagittal view and, finally, an oblique view. The episode of continuous fetal breathing an oblique view. The episode of continuous fetal breathing lasts well in excess of the required 20-second period.lasts well in excess of the required 20-second period.

False fetal breathing movements. Although some transient False fetal breathing movements. Although some transient fetal breathing movements are seen, the video does not fetal breathing movements are seen, the video does not include 20 seconds of continuous fetal breathing. Note that include 20 seconds of continuous fetal breathing. Note that the maternal breathing and aortic pulse seen posteriorly and the maternal breathing and aortic pulse seen posteriorly and the fetal aortic pulse seen on the sagittal view, along with the fetal aortic pulse seen on the sagittal view, along with fetal cardiac activity, can cause deflections of the fetal chest fetal cardiac activity, can cause deflections of the fetal chest wall, which can be mistaken for fetal breathing movements.wall, which can be mistaken for fetal breathing movements.

Gross fetal movements and tone. Video Gross fetal movements and tone. Video demonstrates generalized movements of the demonstrates generalized movements of the fetal lower extremities, including 1 episode of fetal lower extremities, including 1 episode of flexion and extension.flexion and extension.

Gross fetal movements and tone. Video demonstrates Gross fetal movements and tone. Video demonstrates generalized movements of the fetal upper extremities. generalized movements of the fetal upper extremities. The upper extremity rests in front of the fetal chest and The upper extremity rests in front of the fetal chest and chin. Although the ultrasound transducer is moving chin. Although the ultrasound transducer is moving laterally across the maternal abdomen, 2 distinct laterally across the maternal abdomen, 2 distinct episodes of flexion and extension are seen. Note the episodes of flexion and extension are seen. Note the many cross-sectional views of the 3-vessel umbilical many cross-sectional views of the 3-vessel umbilical cord and the floating echogenic particles of vernix in the cord and the floating echogenic particles of vernix in the amniotic fluid.amniotic fluid.

Amniotic fluid index. The largest pocket of fluid Amniotic fluid index. The largest pocket of fluid is measured in each quadrant of the maternal is measured in each quadrant of the maternal abdomen in the vertical dimension. Then, each abdomen in the vertical dimension. Then, each value is added to yield the amniotic fluid index.value is added to yield the amniotic fluid index.