Fetal Biophysical Profile in high risk pregnancy Presented

Fetal Biophysical Profile in high risk pregnancy Presented by: Dr. S. Rouholamin

§ Hypoxia : Low Oxygen tension § Asphyxia : Low Oxygen and high CO 2 § Ischemia : Drop in blood flow

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

§ 18 -48 hrs(Neuronal necrosis) 48 -72 hrs(apper. of white matter macroph. &Astrocy. ). >4 days cavitation visible on head U/S

comment § Fetal asphyxia may or may not be concomitant with clinical presentation. (based on severity , duration & location of insult)

Component Fetal movements Definition 3 body or limb movements Fetal tone One episode of active extension and flexion of the limbs; opening and closing of hand Fetal breathing episode of >= 30 seconds in 30 movement minutes Hiccups are considered breathing activity. Amniotic fluid volume single 2 cm x 2 cm pocket is considered adequate. Non-stress test 2 accelerations > 15 beats per minute of at least 15 seconds duration.

§ 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

The biophysical profile score is continued for a maximum of 30 minutes Oligohydramnios is now defined as a pocket of amniotic fluid < 2. 0 x 2. 0 cm (Manning, 1995 A)

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 p. H falls below 7. 2. • If the fetal p. H 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 not necessarily remain) at least 15 beats per minute above the baseline and last 15 seconds from baseline to baseline within a 20 -minute period with or without fetal movement discernible by the woman. Amniotic fluid volume A single 2 cm x 2 cm pocket is considered adequate or AFI greater than 5. 0 cm. Fetal breathing movements One or more episodes of rhythmic fetal breathing movements of 30 seconds or more within 30 minutes. Hiccups are considered breathing activity. Fetal movements At least three discrete body or limb movements. Episodes of continuous movement are considered as a single movement. Fetal tone One or more episodes of extension of a fetal extremity or trunk with return to flexion, or opening or closing of a hand

Perinatal Mortality and the Biophysical Profile 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 abruption Fetomaternal hemorrhage Diabetic ketoacidosis Cord prolapse Sickle cell crisis Ruptured membranes Drug overdose Vase previa Motor vehicle accident Cord entanglement Acute myocardial infarction Umbilical artery Acute alcohol poisoning thrombosis

Factors 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 v. Rupture of the membranes does not alter the shortterm sonographic variables of the biophysical profile in the healthy fetus. v. The negative predictive value of a normal biophysical profile score is not as high with an anomalous fetus, in contrast to a structurally normal fetus. v. Sudden fetal deaths have been reported following a normal biophysical profile score in fetuses with gastroschisis, omphalocele, and diaphragmatic hernia.

Special Considerations v. The observation of an abnormal biophysical profile in an anomalous fetus does not correlate very well with the presence of hypoxia. v. The biophysical profile score cannot be used in fetuses with congenital muscular diseases or central nervous system conditions that would affect muscular function. v. If an anomalous fetus had a previously normal biophysical profile score, a decreasing score should be considered an indication of compromise

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

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

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

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

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