ANTEPARTUM FETAL SURVEILLANCE BY DR PROMISE OKEKE_071532.pptx

Antepartum Fetal surveillance

1. Antepartum Fetal Surveillance BY DR. IKECHUKWU PROMISE OKEKE Registrar,Department of Obstetrics & Gynaecology Modibbo Adama University Teaching Hospital, Yola Moderator : Dr Fatima Muhammed Girei

2. Outline Introduction Indications Timing Methods -clinical -biophysical -biochemical Conclusion

3. Introduction Antepartum fetal surveillance refers to the monitoring of a fetus's well-being in the antenatal period. Antepartum surveillance aims to detect potential problems like fetal hypoxia and acidosis, thus reducing perinatal morbidity and mortality. The ultimate aim of Antepartum Fetal Surveillance is to reduce the risk of stillbirth and other adverse outcomes by identifying fetal compromise and enabling timely interventions.  Also helps to detect normal fetus to avoid unwarranted interventions.

4. Indications for Antepartum Fetal Surveillance Maternal Medical Conditions Hypertension in pregnancy, including Preeclampsia/Eclampsia Diabetics in pregnancy Maternal Connective tissue disorder like SLE Antiphospholipid syndrome In Vitro Fertilization Substance abuse Thyroid disease Renal Disease Anaemia in Pregnancy Heart Disease. Acute illness- severe malaria. Sickle cell disease patient Maternal age >35years

5. Fetal Indication Intrauterine fetal growth restriction Decrease Fetal movement Fetal anaemia Rhesus isoimmunization Fetal infection Fetal cardiac arrhythmia Fetal abnormality .

6. Pregnancy-related History of previous adverse outcomes, such as preterm delivery Multiple pregnancy Abnormal serum marker Chronic Placenta Abruption Abnormal placentation Oligohydramnios Polyhydramnios PROM Cholestasis Previous unexplained stillbirth Post-term pregnancy

7. Timing Depends on The gestational age of the fetus is usually from 32 weeks. But sometimes it may be earlier. Severity of the indications History of previous adverse outcome and the gestational age

8. Methods of Antepartum Surveillance There are various methods Clinical Gestational age Maternal perception of fetal movement Weight gain Symphysio -Fundal height measurement Abdominal girth measurement Counting of Fetal movement Fetal heart rate Auscultation Radiological: Ultrasonography and Doppler Biochemical test- Fetal lung maturity

9. Methods of Antepartum Surveillance Biophysical Non stress test Contraction stress test Biophysical profile Modified Biophysical profile

10. Clinical Assessment Weight The recommended amount of weight gain varies based on pre-pregnancy weight. Generally, women of healthy weight gain between 11.5kg to 16 kg.  The average weight gain is 12kg It's normal to gain 1-2 kg in the first trimester After that, 0.5 kg a week is typical during the rest of the pregnancy Women carrying twins or multiples will need to gain more weight Extreme weight gain in pregnancy and the rate of weight gain are one of the ways to assess the fetus Poor weight gain and excessive weight gain both have implications.

11. Symphysio -Fundal Height Measurement Symphysio -Fundal height measurement is a simple, non-invasive way to assess fetal growth during pregnancy.  It involves measuring the distance in cms from the pubic bone to the top of the uterine fundus Correspond to gestational age from the 20th week. A difference of more than 2cm warrants further evaluation to ascertain the cause of the discrepancy Difference of < 2cm could be IUGR ,Oligohydramnios or constitutional

12. Abdominal girth Not commonly used Abdominal circumference measurements, along with fundal height, are used to monitor fetal growth and assess gestational age Measured at the level of the umbilicus, around the abdomen It is about 95-100cm at term It increases by 2.5cm per week after 30 weeks Declining values or stagnant values are alarming signs.

13. Fetal Movement Count Many clinicians use maternal-fetal movement assessments, or kick counts, to monitor fetal well-being easily. This is based on reports of a reduction in the mother's awareness of fetal movements preceding fetal demise by several days. Fetal movement corresponds to the active state of the fetus. Fetal movement lasts about 40 seconds with about 75 seconds rest period. Mothers appreciate 88% of fetal movement

14. Perception of fetal movement is affected by Fetal sleep Placenta location Amniotic volume Abruptio placenta Obesity Parity Anxiety Drug

15. Various kick count protocols exist, with no established optimal number or duration. Cardiff count to 10: 10kicks in a maximum period of 12hours Jerusalem fetal kick count: 10 kicks in 2hours, done two hours after breakfast, lunch, and dinner. Daily total fetal movement count- cumbersome and not used in clinical practice

16. How to Count Fetal Kicks Choose a time Comfortable Position Record the movements Monitor the time Report concerns

17. Fetal Heart rate Measurement Fetal heart rate can be measured using Pinard Doppler Sonicaid The normal fetal heart rate is between 110 and 160beats/min

18. Radiological

19. Radiological Assessment: Ultrasound Scan Ultrasound provides vital information about fetal development and well-being throughout pregnancy. Used for -viability -liquor volume -biophysical profile -estimated fetal weight -congenital anomalies -Quintero classification in TTTS

20. USS and Fetal Anomaly USS would diagnose Cardiac anomaly Cystic hygroma Diaphragmatic hernia Duodenal atresia Tracheoesophageal fistula Twin-to-twin transfusion syndrome

21. Radiological Assessment Doppler studies Uterine artery doppler Umbilical artery doppler Middle cerebral artery Ductus venosus doppler

22. Doppler Velocimetry Fetal doppler velocimetry is a type of ultrasound test used to assess blood flow in the fetal circulation, specifically measuring the velocity and resistance of blood flow in fetal vessels. A valuable tool for monitoring fetal well-being, particularly in high-risk pregnancies, as it detects intrauterine growth restriction (IUGR), fetal anaemia or fetal distress It measures the velocity and direction of blood flow in fetal vessels, such as the umbilical artery and middle cerebral artery, to evaluate fetal well-being and detect potential complications.  

23. Doppler ultrasound uses sound waves to measure the speed and direction of blood flow within vessels.  In fetal Doppler velocimetry, the ultrasound transducer is placed on the mother's abdomen to direct sound waves toward the fetal blood vessels.  The machine then analyzes the reflected sound waves to create a waveform that represents blood flow velocity over time

24. It utilizes ultrasound technology to measure the speed and direction of blood flow within fetal vessels.  The Doppler effect, where the frequency of sound waves changes as they reflect off moving objects (like blood cells), is used to calculate these velocities. It involves studying 3 fetal and 1 maternal vascular circuit Umbilical artery Middle cerebral artery Ductus venosus Uterine artery

25. The test can assess various parameters, including: Pulsatility Index (PI):  Measures the resistance to blood flow in a vessel Resistance Index (RI):  Also measures resistance to blood flow, similar to PI Systolic/Diastolic Velocity Ratio:  Compares the peak systolic velocity to the end-diastolic velocity to assess blood flow Early Diastolic notching Presence of unilateral or bilateral diastolic notching Abnormality in these indices are defined as PI or RI above a chosen value and/or percentile

26. Indications IUGR Hypertensive disorders Rhesus Isoimmunization Fetal anaemia

27. The test is generally considered safe and non-invasive. It's best performed between 32 and 40 weeks of gestation, although it can be done earlier. Abnormal venous Doppler indices mandate higher testing frequency, up to daily testing. Detect fetal compromise early. Guide decisions about delivery. Reduces perinatal mortality and morbidity.

28. Vessel/study Normal pattern Abnormal Change Severe/Abnormal Interpretation Clinical Implication Uterine artery No notch after 24 weeks,PI normal Persistent notch PI ↑ ----- Placental resistance Risk IUGR,PE-monitor closely early aspirin Umbilical artery low PI ,forward diastolic flow PI ↑ AEDF/REDF Placental insufficiency AEDF- ↑surveillance/delivery ≥ 32wks,REDF →urgent delivery MCA High PI, PSV normal ↓ PI(<5th percentile)-Brain sparing PSV >1.5Mom (Anemia) Hypoxia or anemia Brain sparing= ↑monitoring;anemia→cordocentesis/ Cerebroplacental ratio >1.0 <1.0 --- Redistribution to the brain low CPR →↑ monitoring Ductus venosus Positive a-wave Absent a- wave Reversed a- wave Cardiac compromise late sign →urgent delivery if viable Umbilical vein Continous flow -- Pulsatile flow Cardiac failure Pre-terminal deliver if viable →

29. Summary STAGE UMBILICAL ARTERY MCA DUCTUS VENOSUS INTERPRETATION EARLY ↑ RESISTANCE NORMAL NORMAL COMPENSATED MID ↑ RESISTANCE ↓PI(BRAIN- SPARING) NORMAL MILD HYPOXIA LATE AEDF/REDF ABNORMAL ABSENT REVERSED a-wave Cardiac compromise END -- --- REVERSED a-wave Pre-terminal, Urgent delivery

30. Biophysical

31. Non Stress Test(NST) Was first described in 1975 by Freeman A common, non-invasive prenatal test used to assess fetal well-being by monitoring the fetal heart rate and its response to movement It is based on the fact that stimulation of a non-hypoxic fetus causes acceleration of the heart rate. The FHR and Uterine activity are monitored with an external transducer (CTG or Doppler Sonicaid ) The FHR is monitored for 20minutes (in EXTENDED NST for 40 minutes) Generally performed after 28weeks.

32. Some definitions Baseline rate is the average heart rate of the fetus within a 10 minute window.110-160B/M

33. Variability Variability refers to variation of fetal heart rate from one beat to the next, excluding accelerations and decelerations. This beat-to-beat variabilty is also known as fetal heart rate variability. Normal variability is between 5-25bpm.

34. Accelerations Accelerations : are an abrupt increase in the baseline FHR of greater than 15bpm lasting at least 15 seconds

35. Decelerations Decelerations are an abrupt decrease in the baseline FHR of greater than 15bpm for more than 15 seconds.

36. Processes Monitoring: The NST is used to monitor the fetal heart rate and any associated abnormality such as decelerations. Fetal Movement:  The test observes the fetal heart rate response to fetal movements. Fetal movement is noted with the use of an event marker. Ideally, the heart rate increases when the baby moves. Duration:  The test typically lasts for 20-40 minutes, but may be longer if needed. Possible Interventions:  If the fetus does not move much, a small acoustic device or a gentle rub on the mother's belly may be used to stimulate movement. No Medication:  No medications are given during the test

37. Interpretation of NST Reactive NST is the presence of 2 accelerations of 15 beats per minute above baseline for 15seconds in a 20-minute time period with or without fetal movement Non-reactive NST is the absence of 2 accelerations in 40 minutes with or without acoustic stimulation over 40 minutes. With a reactive NST, the chance of fetal death in 1 week is 1.9 per 1000 Reactive NST is reassuring Non-reactive NST is non-specific and requires further evaluation. In high-risk pregnancy, increase the frequency of NST to twice weekly

38. Vibro -acoustic Stimulation test Is rarely done in this environment Is used as an adjuvant to NST Based on the physiological fact that the brain stem responds functionally at 26 to 28 weeks of gestation VAST increase in reactive NST after 26 weeks Involve the use of an artificial larynx that generates sound 82 Decibel -100 Decibels with a frequency of 80Hz A stimulus for 3 seconds or less is applied near the fetal head. If NST remains non-reactive, the stimulus is repeated at a 1-minute interval up to 3 times. VAST has reduced the incidence of non-reactive NST from 14% to 6%.

39. Contraction Stress Test A contraction stress test (CST), also known as an oxytocin challenge test. It is a prenatal test used to assess how well a baby tolerates the stress of contractions during labor CSTs are typically performed after 34 weeks of gestation It is based on the response of the fetal heart to uterine contraction during labour. It monitors the fetal heart rate in response to uterine contractions, which can be induced by nipple stimulation or medication like Pitocin (synthetic oxytocin).  The test helps determine if the placenta is providing adequate oxygen to the fetus during contractions, which is crucial for a healthy delivery

40. CSTs are often performed when there are concerns about fetal well-being, such as after a nonreactive non-stress test or as part of a biophysical profile The test is generally considered safe, but it carries the risk of inducing preterm labour It is rarely used now.

41. Technique A fetal heart rate monitor (usually a CTG or Doppler Sonicaid ) is attached to the mother's abdomen Uterine contractions may be induced using a low dose of intravenous oxytocin or by nipple stimulation The fetal heart rate is observed for any decelerations that occur after the contraction.

42. Interpretation Negative CST:  A negative result indicates the fetal heart rate remains stable and shows no decelerations after contractions, suggesting the fetus can tolerate labour. Positive CST:  A positive result indicates late decelerations in the fetal heart rate after more than half of the contractions It suggests the fetus may be under stress and unable to tolerate labor.  In such cases, further monitoring or a cesarean section may be recommended Equivocal/Suspicious:  If the results are unclear, the test may be repeated or other tests like a biophysical profile may be considered.

43. Contraindications to CST Placenta praevia Previous CS Multiple gestation Polyhydramnios History of preterm Incompetent cervix

44. CST is often recommended when a non-stress test or biophysical profile suggests potential fetal distress or when there are concerns about the fetus ability to handle labour. Potential risks: The primary risk of a CST is that it can induce labor or uterine contractions, potentially leading to preterm birth

45. Biophysical Profile Described by Manning and colleagues Is a thorough evaluation of fetal well-being. It is based on the fact that the CNS controlling the fetal biophysical activities is sensitive to varying degrees of hypoxia. It significantly reduces the false positive rate of NST/CST

46. A biophysical profile (BPP) is a prenatal test that assesses fetal well-being, typically in the third trimester, using ultrasound and sometimes a non-stress test.  It evaluates fetal heart rate, breathing, movements, muscle tone, and amniotic fluid volume.  The results are scored. A score of 8-10 is generally considered normal.  A low score may indicate potential fetal distress or the need for further evaluation or intervention.  

47. Ultrasound:  The ultrasound portion of the BPP assesses fetal breathing movements, body movements, muscle tone, and amniotic fluid volume.  Non-Stress Test (NST):  This test monitors the fetal heart rate, using CTG to measure the fetal heart rate in response to fetal movement. 

48. The BPP integrates 5 parameters to yield a biophysical profile score (BPS): Called Manning Score The nonstress test (NST) Ultrasonographic measurement of the Amniotic Fluid Volume Observation of the presence or absence of fetal breathing movements Gross body movements Tone Each parameter is given a minimum score of 0 and a maximum score of 2, and the maximum total score is 10. A score of 8-10 is Normal , 6 is considered Equivocal and it need to be retested in 24 hours, and 4 or less is Abnormal (2-4 is not reassuring, while 0 needs urgent delivery)

49. Biophysical Variable Normal (Score = 2) Abnormal (Score = 0) Fetal breathing movements* 1 or more episodes of ≥20 s within 30 min Absent or no episode of ≥20 s within 30 min Gross body movements 2 or more discrete body/ limb movements within 30 min (episodes of active continuous movement considered as a single movement) < 2 episodes of body/limb movements within 30 min Fetal tone 1 or more episodes of active extension with return to flexion of fetal limb(s) or trunk (opening and closing of hand considered normal tone) Slow extension with return to partial flexion, movement of limb in full extension, absent fetal movement, or partially open fetal hand Reactive FHR 2 or more episodes of acceleration of ≥15 beats per minute (bpm) and of >15 s associated with fetal movement within 20 min 1 or more episodes of acceleration of fetal heart rate or acceleration of < 15 bpm within 20 min Qualitative AFV 1 or more pockets of fluid measuring ≥2 cm in vertical axis Either no pockets or largest pocket < 2 cm in vertical axis

50. Modified Biophysical Profile (MBPP) A prenatal test that combines a nonstress test (NST) with an ultrasound assessment of amniotic fluid volume .  It's a simplified version of the standard biophysical profile (BPP) and is used to assess fetal well-being.  The MBPP is considered a less time-consuming and less cumbersome alternative to the full BPP, while still providing valuable information about fetal well-being

51. Component The MBPP includes two key components: Nonstress Test (NST):  Measures the fetal heart rate in response to fetal movement, indicating the baby's well-being. Amniotic Fluid volume:  Assessed using ultrasound to determine the amount of amniotic fluid surrounding the baby, which can reflect placental function.

52. Scoring While the standard BPP has a scoring system, the MBPP is often interpreted as either normal or abnormal based on the results of the NST and amniotic fluid volume Normal:  A reactive NST and adequate amniotic fluid volume (usually defined as AFI >5cm or single deepest pool > 2cm) are considered normal Abnormal:  An abnormal NST (nonreactive) or oligohydramnios (low amniotic fluid volume, often defined as a deepest vertical pocket of 2 cm or less) is considered Abnormal and it indicates a potential problem

53. Biochemical Tests

54. Tests for Fetal Lung Maturity Assess the readiness of the fetus for life following delivery These tests are crucial when there is a risk of preterm birth Typically involves measuring the levels of surfactant in the amniotic fluid. Lecithin/Sphingomyelin (L/S) Ratio: This test measures the levels of lecithin and sphingomyelin, two components of surfactant, in the amniotic fluid Phosphatidylglycerol (PG) Detection: PG is another important component of surfactant. Its presence indicates a higher level of lung maturity

55. Lamellar Body Count: Lamellar bodies are structures that store and secrete surfactant. Counting them in amniotic fluid can help assess lung maturity Surfactant/Albumin Ratio: This test measures the ratio of surfactant to albumin in the amniotic fluid using fluorescent polarization Shake or Bubble test Foam Stability test Nile blue sulphatase test

56. Conclusion Antepartum fetal surveillance is a vital aspect of modern obstetric care aimed at assessing fetal wellbeing, especially in high-risk pregnancies using appropriate tools such as; non-stress test, biophysical profile, Doppler studies , and fetal movement counting to identify fetuses at risk of compromise , allowing for prompt intervention to avert adverse perinatal outcome.

57. References Damale NRK, Larsen-Reindorf RE. Fetal Surveillance. In: Comprehensive Obstetrics in The Tropics. Chapter 6;p.42-51 Dutta DC. Fetal Surveillance. In:Dutta DC, editor. Textbooks of Obstetrics. 8th ed. New Delhi: Jaypee Brothers Medical Publishers;2015. p.463-474

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