Biophysical profile

1. Biophysical profile Samia MohamadEid Assist. Prof of Obs & Gyne. Al-Azhar university

2. BPP is applying to detect prenatal asphyxia • Doppler ultrasound is a modality for detecting fetal hypoxia and acidosis.

3. Hypoxia: decrease oxygen concentration in the tissue & blood. • Acidosis increase concentration of H+ in tissue & blood. • Asphyxia: hypoxia & metabolic acidosis. • Ischemia: Drop in blood flow

4. How hypoxia leads to acidosis The fetus uses oxygen to "burn" molecules and release energy. The reaction: glucose + oxygen >> carbon dioxide + water + energy Poor blood flow from the uterus and placenta causes the fetus to constrict blood vessels in nonvital peripheral areas in order to supply more blood flow to vital organs such as the heart and brain.

5. How hypoxia leads to acidosis • With a limited supplies of oxygen (hypoxia) the peripheral tissues can only partially break down the sugar and converts it to lactic acid. • Significant levels of acid in the blood (acidemia) may suppress the fetal nervous system and eventually lead to cardiovascular collapse.

6. In 1980, Maning and Platt fashioned a method for Fetal surveillance in high risk pregnancy that combine FHR with various US variable

7. Biophysical profile • FHR monitoring • Fetal breathing movement • Fetal movement • Fetal tone • Amniotic fluid assessment

8. 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 non-stress test is most reliable between 32 weeks and term

9. Comment • So ,BPP has a limited role for assessing fetal well being before 32 gestational weeks.

10. Timeline for fetal hypoxia

11. comment • So, Doppler ultrasound can predict fetal distress sooner than BPP

12. FHR monitoring • It involve the ability of the hypothalamus and medulla to maintain a variable, rather than smooth baseline and to increase the heart rate with fetal movement. • Hypoxia or acidosis decrease beat-to-beat variability and accelerated FHR with fetal activity.

13. Fetal breathing • Fetal breathing movements are detectable by, at least 17-18 weeks’ gestation . • After 30ws of gestation, the fetus will spend about 30%of his time making breathing motion.

14. Fetal breathing • Action generated in the ventral surface of the 4th ventricle . • One episodes of 3oseconds during an observation period of up to 20 minutes. • Prolonged hypoxia and/or acidemia blunt this activity.

15. Fetal movement • The fetal cortex generate the massage for the fetus to move his/her arms, legs, trunk. • At least 3 trunk movements during 20 minutes observation period. • Profound hypoxia and • Acidemia • will stop this for happening

16. Fetal tone • Depends on intact cortex and subcortex. • One episode of extension with a return to flexion during--------. • Is the last to go in a sequence of events ending in severe fetal compromise. • Actually, fetal tone is the least useful variable since, By the time tone is lost , all of the other categories will have had scores zero (unless ---------------?)

17. Amniotic fluid assessment Amniotic fluid relates indirectly to fetal brain Brain sparing concept Except post term pregnancy

18. Assessment of AF. AF volume rise linearly to about 33-34ws when the average is about 1000cc. After which it generally drops slowly to about 800cc at 40 ws and to 600cc at 42ws

19. Assessment of AF • Basically there are 3 methods commonly used to assess the adequacy of AF: • Vertical pocket technique. • Amniotic fluid index. • subjective (eyeball) assessment.

20. Vertical pocket technique 1 cm oligohydramnios 2cm oligohydramnios

21. AFI

22. As you know, oligohydramnios may be • Mild AFI=5-8cm • Moderate AFI=2-5cm • Sever AFI<2cm • only sever oligohydramnios is considered as an abnormal score.

24. subjective (eyeball) assessment. • It is not to obsess about subjective technique. • I think that SA of AF by an experienced operator is at least a good as any other attempt since the aim is to determine if there is too little or too much.

25. oligohydramnios • IUGR • Fetal renal abnormalities • PROM • 1ST place to star would be fetal kidney. • Kidneys circumstance should be 1/3 of AC. • Texture should be mildly heterogeneously echogenic IPCK MDKD ++

26. oligohydramnios • +IUGR = MCA Doppler • Increased diastolic flow • +AGA ? • The fetal demands outstrips the placental ability to keep up & the circulatory cascade enfolds that is similar IUGR. • These mothers often go into labor soon after Doppler change,

27. Oligohydramnous • PROM ?? • Sometimes the history is equivocal or not helpful, in this case once renal anomalies excluded & normal MCA Doppler • TVUS optimize axial section , the membrane can be seen over the cervix.

29. How the BPP relates to fetal behavior

30. Under the influence of progressive hypoxia , the characteristic behavior pattern linked to these portion of the brain are lost in reverse order. • NST become non reactive & the respirations are lost at roughly the same level of PO2 however FM slow & stops at lower PO2 . • The last to be affected is the fetal tone.

31. 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 are abolished. Normal umbilical artery PH 7.27 ± 0.6

32. The fetal sleep states • FST affects on fetal behavior especially HR, respirations & movements. • Quiet sleep (f1 25-30%) (20-------------------40min) • Active rapid eye movement (F2 60-70%) • Quit awake sleep • Active awake sleep

33. The efficacy 0f bpd

34. Modified BPP • NST indicates acute hypoxia • AFI speaks for chronicity of the problem.

35. Doppler velocity Increased umbilical artery resistance Cartelization of flow Absent umbilical artery diastolic flow. Reversed umbilical artery diastolic flow. Ductusvenosus Doppler.

36. Comment • Doppler ultrasound can predict fetal distress sooner than BPP • BPP bring fetal CNS to the diagnosis.