assement of fetal well being
DESCRIPTION
ante natal assement of fetal well beingTRANSCRIPT
1
Antepartum assessment of fetal well being
Presented by Dr. Pankaj sharma igmc shimla [email protected]
2
HISTORY• Fetal heart sounds first detected
by Marsac in the 1600A.D. • Can be used to determine fetal
well being was first proposed by Killian in the 1600’s.
• Mayor and Kergaradec described the method of auscultating fetal heart sounds by placing the ear next to the maternal abdomen. .
• In 1893, Von Winkel established criteria for fetal distress that remained unchanged until the advent of electronic fetal monitoring
3
INTRODUCTION• ANTENATAL FETAL SURVEILLANCE IS
ASSESSMENT OF FETAL WELL BEING IN ANTEPARTUM PERIOD TO ENSURE DELIVERY OF HEALTHY NEONATE.
Two main objectives are:- Early detection of fetuses at
risk to prevent perinatal mortality and morbidity.
Find out normal fetuses and avoid unwarranted interventions.
4
ANTEPARTUM FETAL ASSESSMENT
• METHODS:-• 1a CLINICAL ASSESSMENT• Weight gain• Fundal height• Abdominal girth• Auscultation of fetal heart• 1b fetal movement count by mother• 2.ultrasound for fetal parameters• 3.biochemical tests• 4.NST• 5.VAST• 6.CST
5
• 7.Nipple stimulation test• 8.biophysical profile• 9.doppler• 10.fetal lung maturation test• 11.placental grading
6
INDICATIONS
• MATERNAL • FETAL • PREGNANCY RELATED• MATERNAL• Hypertension • Diabetes• Heart disease• Chronic renal disease• Sever anemia• APLA• Acute illnesses
7
Fetal
• Fetal growth restriction• Rh isoimmunisation• Fetal cardiac arrythmias• Fetal infections
8
PREGNANCY RELATED• Multiple pregnancy• Gestational hypertension• Preeclampsia• Decreased fetal movement• Abnormal placentation• Placental abruption• Amniotic fluid disorders• PROM• GDM• Previous unexplained still birth• ICP• Post term pregnancy
9
WHEN TO START?
• Depends up on factors like:-• Past history of adverse outcome• Severity of maternal and fetal
conditions• Generally Monitoring is
recommended when estimated fetal maturity is sufficient to expect a reasonable chance of survival should intervention be necessary.
10
CLINICAL ASSESSMENT• WEIGHT GAIN
Recommended Ranges of Weight GainDuring Singleton Gestations Stratified by Pre pregnancy Body Mass Index
Category BMI Wt. in kgs kgLow 19.8 12.5–18Normal 19.8–26 11.5–16High 26–29 7–11.5Obese 29 7(Williams 23rd ed.)
11
Symphysio-fundal height
• Measured from superior border of pubis symphysis to fundus
• From 24th wks of gestation corresponds to period of gestation .
• Difference of 3-4 cms acceptable
• below 10th percentile or difference of >4cms suggests IUGR
• positive predictive value of60% negative predictive value of 76.8%
12
Abdominal girth• Measured at lower border of
umbilicus.• Increases by 2.5cm per week
after 30wks.• 95-100cms at term.• Static or falling values alarming
sign.
13
Fetal movement count• Cardiff” count 10” technique• Daily fetal movement count• Perception of three movement
in 30 minutes. • Sadovsky’s “movement alarm
signal”fewer than three movements an hour for 2 consecutive days.
GABBE 6TH ED.
14
Fetal movement count
• Fetus spends 10% of its time making gross fetal body movements
• 30 such movements made each hour.
• Periods of active fetal body movement last about 40 minutes
• Quiet periods last about 20 minutes.
• Longest period without fetal movements about 75 minutes.
• Mother appreciate 70% to 80% of gross fetal movements.
• (GABBE 6TH ED.)
15
• Fetal movement peak between 9:00 PM and 1:00 AM.
• Time when maternal glucose levels are falling.
• Holden and coworkers hypoglycemia associated with increased fetal movement.
Fetal activity does not increase after meals or after maternal glucose administration.
(GABBE 6TH ED.)
16
• Cochrane review of four trials in 2007 concluded that there is insufficient evidence to recommend routine fetal movement counting to prevent fetal death.
• positive predictive value of the maternal perception of reduced FM for fetal
compromise 2% to 7%• Despite these results, there may be
some advantages to this type of fetal assessment.
17
Factors affecting maternal perception of fetal movement
• Fetal and placental factors :-• Placental location• The length and type of fetal
movements• Amniotic fluid volume (AFV)• Maternal factors :-• Parity, obesity.• Psychological factors anxiety.
18
• Froen and associates, found in a cohort of 1200 women instructed to start their fetal movement count at the first convenient time of the day that the mean time to count to 10 was less than 10 minutes.
(GABBE 6TH ED.)
19
ULTRASOUND FOR FETAL PARAMETERS
• HIGH RESOLUTION UTRASOUND REVOLUTIONIZED PRENATAL DIAGNOSIS.
• CAN BE:-• BASIC• TARGETED• BASIC:-(in early pregnancy)• Done at 10-14wks and includes :-• No. of fetuses• Fetal life• Placental localization• Internal os diameter• Cervical length
20
• Gestational age• maternal pelvic masses• Any gross anomaly like
anencephaly,limb reduction defects.• Nuchal translucency(80% fetuses with
5% false positive rates)
• Only in high risk patients
21
• CRL smaller than gestational age
chromalsomal anomaliesAbsencence of nasal bone at 10-12wks
Down syndrome
NB+NT detection rate of 92% & false positive rate of 3.5%
Dutta 7th ed.
22
2nd &3rd triemester• Serial measurements of BPD,AC,HC,FL.• HC/AC ratio exceeds 1 before 32wks.• 1 bw 32to 34wks. After 34wk falls below 1.• In symmetric IUGR remains normal.• Ratio can identify 85% IUGR fetuses.• FL/AC remains 22 at all gestational ages
from 21wks to term. >23.5 suggest IUGR.• AC remains single best parameter to detect
IUGR with positive predictive value of 50%.• Trans cerebellar diameter in mm corresponds
to POG from 11wks – 32wks .• (James 4th ed.)
23
AMNIOTIC FLUID VOLUME
• Single deepest pocket >2cm normal• Or• Amniotic fluid index 5-25cm. (five
quadrant technique.)
24
Targetted ultrasound • Done in high risk patients• In developed countries offered to all patients• Transverse section for fetal head• Shape and internal structures. BPD,HC Measured
to detect hydrocephalus,anencephaly• Transverse and longitudinal views of abdomen
to rule out anomaliesofstomach,kidneys,bladder,ventral wall.
• Transverse section of fetal thorax to four chambered view of heart.
25
Four chambered view of heart
26
• Identify three long bones in each limb
and any achondroplasia is iooked for.• Saggittal ,coronal and transverse
views taken to rule out spinabifida.
cephalic index Biparietal diameter/occipitofrontal diameter • Age-independent• Identify dolichocephaly and brachycephaly.
27
Fetal ECHO
• IndicationsFetal risk factors • Suspected cardiac anomaly on level I scan • Nuchal thickening/lucency
• Diaphragmatic hernia • Duodenal atresia • Tracheoesophageal fistula • Cystic hygroma
• Chromosomal abnormalities • Twin–twin transfusion
• Acardiac twin • Vein of Galen aneurysm
(Nadas' Pediatric Cardiology, 2nd ed.)
28
• Maternal risk factors • • Congenital heart disease
• Exposure to teratogen • Diabetes• Maternal infections
Familial risk factors • Trisomy 21 (Down) • Marfan • Noonan • Tuberous sclerosis • Velocardiofacial/DiGeorge
(Nadas' Pediatric Cardiology, 2nd ed).
29
• Historically optimal timing between 18 and 22 weeks’ gestation.
• moving into an era of early risk assessment .
• fetal echocardiography late first and early second trimesters
• A limited number of reports describe the utility of transvaginal imaging between 10 and 13 weeks.
(Ultrasound Clin 6 (2011) 47–56)
30
Non stress test
• Freeman first described the NST in 1975.• Physiologic premise of the NST is that:- Nonhypoxic fetus
stimulus
•
• • accelerate its heart rate
31
Method
• Patient is placed in a lateral tilt position • FHR and uterine activity are monitored
with an external transducer• FHR is monitored for 20 minutes.• For 40 minutes in some cases to
compensates for sleep cycles then called EXTENDED NST.
• In some cases when the fetus is not reactive, acoustic stimulation by artificial larynx a sound stimulus for 1 to 2 seconds.
32
INTERPRETATION
• Reactive NST presence of two accelerations of 15bpm over base line for 15sec in a 20-minute time period with or without fetal movements.
• Nonreactive NST absence of two accelerations in a 40-minute period with or without acoustic stimulation over a 40-minute period.
33
WHEN TO START ?• NST is not routinely started until 32-
weeks gestation.• Up to 50% of NSTs reactive from 24-
to 28-weeks gestation.• 85% from 28 to 32 weeks of
gestation• In up to 50% of NSTs variable
decelerations may be observed. • If last for <30 seconds and <2 during
a 20-minute period
NO fetal compromise
34
PREDICTIVE VALUE
• With a reactive NST, the chance for fetal death within 1 week is 1.9 per 1,000, giving a negative predictive value of 99.8% after correction for lethal anomalies.
• Best senstivity and positive predictive value for IUGR and Hypertensive disorders -70%
• Reactive NST is reassuring.• Nonreactive NST is nonspecific
and requires further evaluation. (Pediatr Clin N Am 56 (2009) 489–
504)
35
• The false-positive rate is considerably higher, ranging from 50% to more than 90% in various studies.
• In high-risk pregnancies, the false-negative rate associated with a weekly NST may be unacceptably high.
• In these cases, increasing frequency of the NST to twice weekly may be considered.
• (GABBE 6TH ED.)
36
VIBROACOUSTIC STIMULATION TEST
• Used as an adjunct to NST• If NST non reactive even after 40min
then:-• Continue CTG monitoring till 90min OR Perform BPP OR VAST
37
• Auditory brainstem response functional at 26 to 28 weeks’ gestation.
• VAST increase the incidence of reactive NSTs after 26 weeks’ gestation .
• Reduce the testing time. • artificial larynx that generates sound
82 Db -100db with a frequency of 80 Hz.
38
• A stimulus for 3 seconds or less is applied near the fetal head.
• If the NST remains nonreactive
• Stimulus is repeated at 1-minute intervals up to three times.
• (GABBE 6TH ED.)
39
• VAST have shown a decreased incidence of nonreactive NSTs from 13% to 14% down to 6% to 9%.
• SAFETY• Arulkumaran and associate found:-“ intrauterine sound levels from
VAST were not hazardous to the fetal ear.”
• no long-term evidence of hearing loss in children followed in the neonatal period and up to 4 years of age.
• (GABBE 6TH ED.)
40
MANAGEMENT PROTOCOL OF NST
NST for 20 min Reactive Repeate after 1wk Or earlier if
situation demands
• If non reactive Extend to 40min
• Non reactive VAST Non reactive BPP
41
BIOPHYSICAL PROFILE
• Thorough evaluation of fetal well-being .
• Potential to significantly reduce the false-positive rate of the NST/CST.
• The BPP was initially described by Manning and colleagues in 1980.
• Vintzileos and colleagues subsequently proposed an alternative BPP scoring system.
• Rationale:-Fetal biophysical activities controlled by centers in the fetal brain sensitive to varying degrees of hypoxia.
42
BPP SCORING( MANNING)
1. Movements Three or more gross body movements SCORE
• in a 30-minute period.• Simultaneous trunk and limb 2• movements count as a single• Movement
• Fewer than 3 gross body movements 0• in a 30-minute period
43
CONT.
SCORE
• 2. TONE At least one movement of a limb from• a position of flexion to one of extension, 2• with a rapid return to flexion.
• Fetal limb in extension with no return 0• to flexion with movement• 3.Breathing At least 30 seconds of sustained • FBMs observed over a 30-minute period 2• Fewer than 30 seconds of sustained • FBMs observed over a 30-minute 0
44
Cont.
• SCORE
• 4.AFPAt least a single amniotic fluid pocket• measuring 2 cm in 2 perpendicular planes 2
• No amniotic fluid pocket that 0• measures at least 2 cm • 2 perpendicular planes• 5. NST reactive 2 • NST non reactive 0
45
46
Vintzileos Scoring
• Nonstress test• Score 2 (NST 2): 5 or more FHR accelerations of
at least 15 beats per minutes (bpm) in amplitude and at least 15-second duration associated with FMs in a 20-minute period.
• Score 1 (NST 1): 2 to 4 accelerations of at least 15 bpm in amplitude and at least 15-second
• duration associated with FMs in a 20-minute period.
• Score 0 (NST 0): 1 or less acceleration in a 20-minute period.
47
Fetal movements
• Score 2 (FM 2): at least 3 gross (trunk and limbs) episodes of FMs within 30 minutes.
• Score 1 (FM 1): 1 or 2 FMs within 30 minutes.
• Score 0 (FM 0): absence of FMs within 30 minutes.
48
Fetal breathing movements
• Score 2 (FBM 2): at least 1 episode of fetal breathing of at least 60-second duration within a 30-minute observation period.
• Score 1 (FBM 1): at least 1 episode of fetal breathing lasting 30 to 60 seconds within 30
• minutes.• Score 0 (FBM 0): absence of fetal
breathing or breathing lasting less than 30 seconds within 30 minutes.
49
Fetal tone
• Score 2 (FT 2): at least 1 episode of extension of extremities with return to position of flexion and also 1 episode of extension of spine with return to position of flexion.
• Score 1 (FT 1): at least 1 episode of extension of extremities with return to position of flexion or 1 episode of extension of spine with return to flexion.
• Score 0 (FT 0): extremities in extension. FMs not followed by return to flexion.
50
Amniotic fluid volume
• Score 2 (AF 2): fluid evident throughout the uterine cavity. A pocket that measures greater than 2 cm in vertical diameter.
• Score 1 (AF 1): a pocket that measures less than 2 cm but more than in vertical diameter.
• Score 0 (AF 0): crowding of fetal small parts. Largest pocket less than 1 cm in vertical diameter.
51
Placental grading
• Score 2 (PL 2): placental grading 0, 1, or 2.
• Score 1 (PL 1): placenta posterior difficult to evaluate.
• Score 0 (PL 0): placental grading 3.
Maximal score, 12; minimal score, 0.
• (Clin Perinatol 38 (2011) 47–64)
52
Technique
• Performance of an NST.• For gestations less than 32
weeks, the qualifying criteria for accelerations are greater than 10 bpm, lasting at least 10 seconds.
• Real-time ultrasound • The time required related to fetal
state, with an average of only 5 minutes if the fetus is in a 2F state but over 25 minutes if it is in a 1F state.
53
MANAGEMENT PROTOCOL OF BPP
• 10 Normal; low risk for chronic asphyxiaRepeat testing at weekly to twice-weekly intervals (IN HIGH RISK CASES)
• 8 Normal; low risk for chronic asphyxiaRepeat testing at weekly to twice-weekly intervals
If oligohydroamnios deliver.• 6 Suspect chronic asphyxia If ≥36-37 wk
gestation or <36 wk with positive testing for fetal pulmonary maturity, consider delivery. Otherwise repeat with in 24hrs
• if <36 wk and/or fetal pulmonary maturity testing negative, repeat biophysical profile in 4 to 6 hr.
• deliver if oligohydramnios is present
54
• 4 Suspect chronic asphyxia If ≥36 wk gestation, deliver.
• if <32 wk gestation, repeat with in 24hrs. If repeat score <6 deliver if >6 observe.
• 0-2 Strongly suspect chronic asphyxia Extend testing time to 120 min.
• if persistent score ≤4, deliver, regardless of gestational age
•
55
PREDICTIVE VALUE OF BPP
• To summarize the results of multiple studies, the false-negative rate of a normal BPP is less than 0.1%, or fewer than 1 fetal death per 1000 within 1 week of a normal BPP
56Clin Perinatol 38 (2011) 47–64)
57
• NST and FBM Has highest senstivity• Fetal tone has highest specificity
58
MODIFIED BPP
• Attempt to simplify and reduce the time.
• Focusing on the components of the BPP most predictive of perinatal outcome.
• Two parameters:-• 1. NST indicator of present fetal
condition.• 2. AFI /AFP a marker of long-
term status.
59
Predictive value
• Miller have demonstrated comparable results of the mBPP to the full BPP.
• False-negative rate (or rate of fetal death within 1 week of a normal mBPP) of 0.8 per 1000.
• Modified BPP has a false-positive rate comparable to the NST.
• But higher than the CST and full BPP.
• AFI or DVP under investigation.
(GABBE 6TH ED.)
60
• Chauhan and colleagues found that the AFI led to more diagnoses of oligohydramnios and a higher rate of intervention without improving outcome.
61
Contraction Stress Test
CST/OCT first biophysical technique widely applied for antepartum fetal surveillance.
Principle uterine contractions Reduction in blood flow to the intervillous
space. Inadequate placental respiratory reserve Recurrent late decelerations in response to
hypoxia.
62
TECHNIQUE
Patient is placed in the semi-Fowler’s position at a 30- to 45-degree angle with a slight left tilt .
Fetal heart rate and uterine contraction baseline is determined.
Blood pressure is recorded every 5 to 10 minutes to detect maternal hypotension.
oxytocin started @.5-1 miu /min. An adequate CST requires uterine
contractions of moderate intensity lasting about 40 to 45 seconds with a frequency of three in 10 minutes.
63
INTERPRETATION
Negative: No late or significant variable decelerations
Positive: Late decelerations with at least 50% of contractions
Suspicious: Intermittent late or variable decelerations
Hyperstimulation: Decelerations with contractions longer than 90 seconds’ duration or 2-minute frequency
Unsatisfactory: Fewer than three contractions per 10 minutes or an uninterpretable tracing
64
PREDICTIVE VALUE OF CST
• A negative CST good fetal outcome.
• incidence of perinatal death within 1 week of a negative CST (i.e., the false-negative rate) to be less than 1 per 1000.
65
MANAGEMENT PROTOCOL OF CST
Positive CST is usually repeated in 24 hours .
This is of historical importance . Not used now.
(IANDONALD 6TH ED.,GABBE 6TH ED.)
66
CONTRAINDICATIONS
• Placenta previa• Previous CS• Multiple gestation• Polyhydroamnios• History of preterm • Incompetent cervix
67
Nipple stimulation test
• Alternative method of performing CST
• ACOG Recommends stimulation through light clothing for two minutes at a time with rest interval of five minutes.
• Adequate uterine contractions obtained with in four minutes of stimulation.
• (IANDONALD 6TH ED.)
68
DOPPLER VELOCIMETRY
• Noninvasive technique to assess blood flow by characterizing downstream impedance
• Three fetal AND one maternal vascular circuits :-
Umbilical artery,• Middle cerebral artery • Ductus venosus• Uterine artery
69
INDICATIONS
• IUGR• PIH• GDM• RH ISOIMMUNISATION• INTRAHEPATIC CHOLISTASIS OF
PREGNANCY
70
UTERINE ARTERY
• INDICATIONS
(1) history of Preeclampsia• (2) previous child with IUGR• (3) unexplained high maternal• serum alpha-fetoprotein level• (4) high human chorionic
gonadotropin• level.• (5) thrombophilias
71
The indices used to quantify uterine artery
• systolic (S) to diastolic (D) velocity ratio (S/D)
• pulsatility index (PI)• resistive index (RI)• early diastolic notching.• Abnormalities in these indices are
defined as PI or RI above a chosen value and/or percentile
• the presence of unilateral or bilateral diastolic notches
72
How to calculate indices
• S/D ratio systolic peak velocity/diastolic peak velocity• Resistance index (RI) systolic- end diastolic peak velocity/systolic
peak velocity
Pulsatility index (PI) systolic-end diastolic peak velocity/time
averaged maximum −velocity
73
Facts sheet
• Uterine Doppler screening is commonly performed around 20 weeks.
• increased uterine artery impedance to flow at 20–24 weeks follow-up at 26–28 weeks.
• Cut-off values at 23 weeks' gestation are:-• a mean PI above 1.5–1.61. • mean RI above 0.57–0.58.• Bilateral notches are found in about 25–30% of
pregnancies at 12 weeks.• 10–15% at 20 weeks .• 5% at 24 weeks. • (Juriy W. Wladimiroff, Sturla H. Eik-Nes)
european practice in obst.and gynaecilogy.
74
• sensitivity is up to 85% when performed between 22 and 23 weeks’ gestation.
• high risk patients given low-dose aspirin because of bilateral uterine artery notching at 12 to 14 weeks have an 80% reduction of placental disease
• (James 4th ed.)
75
Cont.
• An early diastolic notch in the uterine arteries at 12 to 14 weeks suggest delayed trophoblast invasion.
• Persistence “notching” beyond 24 weeks
• confirmatory evidence.
• (James 4th ed.)
76
77
• sensitivities and specificities of uterine artery Doppler in low-risk populations varied from 34% to 76% and 83% to 93%, respectively.
• predictive accuracy for early onset preeclampsia was better than for late-onset preeclampsia.
78
• For both preeclampsia and IUGR uterine artery Doppler more accurate in the second than the first trimester.
• Increased PI with notching in the second trimester best predictor of preeclampsia.
• ( Clin Perinatol 38 (2011) 1–19)
79
Placental vascular indices
• Novel tool for estimating placental volume and vascular blood flow.
• Calculated from 3D data formed by the voxels.
• vascularization index (VI) quantifies the• number of color-coded voxels relative to all
voxels within the volume expressed as a percentage.
• Flow index (FI) represents the power Doppler signal intensity from all color-coded voxels,
• ( Clin Perinatol 38 (2011) 1–19)
80
• vascularization flow index (VFI) is the product of VI and FI.
• Reduction in these indices may be an early marker of placental dysfunction.
• • Study in normal and growth-restricted
pregnancies revealed that FI, which identifies the most severe cases of placental impairment, the most reliable index
• . • Deciduo-myometrial VI appeared to be the best
predictor of preeclampsia. superior to uterine artery PI at 12 and 22 weeks
• ( Clin Perinatol 38 (2011) 1–19)• .
81
UMBLICAL ARTERY
• Duplex Doppler ultrasound is the current standard .
• RI,PI, S/D,PSV are used.
82
83
Wave forms at 16,20,24,28,32,36 wks
84
Reverse end diastolic flow
85
FACTS SHEET
• RI had the best discriminatory ability when compared with the S/D ratio
(P<.05), the PI (P<.001). S/D ratio, however, remains the most
popular index.• S/D ratio less than or equal to 3.0.• Resistance index less than or equal to 0.6 is considered normal after 27
completed weeks of pregnancy.
• Benefits of this technique before 28 weeks of gestation are uncertain.
86
87
CONT.
• Diagnostic feature of umbilical artery Doppler waveform is the end diastolic flow.
• Absent or reverse end diastolic flow ominous finding.
• frequency of absent end diastolic flow is approximately 2% in high-risk pregnancies .
• 0.3% in a general obstetric population.• In pregnancies complicated with FGR,
fetal surveillance should consist of weekly umbilical Doppler.
• ( Clin Perinatol 38 (2011) 1–19)• .
88
CONT.
• BPP or NST should be used either as a backup test or simultaneously with the umbilical artery Doppler.
• Umbilical Doppler index is high or increasing
• • • weekly umbilical Doppler ultrasound• +• Twice wkly NST/ BPP
89
MANAGEMENT WITH ABSENT END DIASTOLIC FLOW
• Guided by the gestational age.• >34 completed weeks
Delivery
• Bw 28 to 34 completed conservative
• Daily umbilical artery Doppler, NST, and BPP (or modified BPP)+ Ductus venosus
• Reverse flow at any gestational age beyond 28 weeks Delivery
90
MIDDLE CEREBRAL ARTERY
• Two major applications • Monitoring of IUGR fetuses• Evaluate peak systolic flow in
fetuses at risk for anaemia.
91
MCA in Fetal Growth Restriction
• Hypoxia-induced cerebrovascular dilation
• Impedance decreases
• Increases end-diastolic blood flow
•
92
• Contrast to fetuses with normal growth • Resistance of the MCA is usually higher than
in the umbilical artery.• MCA Doppler useful to monitor the third-
trimester growth restricted Fetus.• Redistribution may occur in the presence of
normal umbilical Doppler.• RI and PI on MCA Doppler in IUGR fetuses
MAINSTAY
93
TECHNIQUE
• Measured at internal third of the vessel
• 50 to 100 waveforms in at least 3 sets examined.
• Highest PSV recorded.
• Impedance to flow decreases and maximum blood velocity increases with advancing gestation.
94
• MCA-PSV new development.• better parameter in the prediction of
perinatal mortality than PI/RI.• MCA PI in IUGR fetuses can
normalize in later stages.• MCA-PSV becomes abnormal,
remains as such.• Ratio of MCA PI to Umbilical PI >1.5 in normal fetal circulatory condition.
95
u
96
97
MCA DOPPLER IN FETAL ANEMIA
• RH isoimmunization• Parvovirusinfection• fetomaternal haemorrhage
98
• Anemic fetus increased cardiac output
• Associated with lower blood viscosity. • So increased blood velocities• Peak velocity in the fetal MCA• value of greater than 1.5(MoMs) for
the corresponding GA
99
100
• MCA-PSV for the prediction of severe, moderate, and mild anemia at a sensitivity of 100% showed false-positive rates of 6%, 37%, and 70%, respectively
• Measurements can be obtained reliably as early as 18 weeks’ gestation.
• Repeated every 1 to 2 weeks depending on the trend.
• Values after 35wks higher rate of false-positive results
• (GABBE 5TH ED.)
101
Ductus Venosus
• Connects the intra-abdominal portion of the umbilical vein with the inferior vena cava at its inlet to the right atrium.
• Shunt plays a critical role in the delivery of well-oxygenated blood to the left side of fetal heart.
• Sample siteInlet, where the highest velocities are recorded
• waveform of the ductus venosus triphasic.
Clin Perinatol 38 (2011) 103–112
102
Ductus venosus waveforms
103
• Blood flow in the ductus venosus is usually forward in physiological conditions.
• In the first trimester (11–14 weeks), a negative a-wave may be recorded in about 3% of normal fetuses.
• Absolute blood flow velocities increase, whereas the pulsatility decreases with advancing gestation.
• This reflecs decreasing cardiac afterload and maturation of diastolic ventricular function.
• Clin Perinatol 38 (2011) 103–112
104
105
• IUGR <32 progressive increase in ductus venosus pulsatility paralleled by decrease of short time variation of the fetal heart rate pattern.
• Parameters normal in late-onset growth restriction.
• Primary value in early-onset FGR.• Perinatal mortality increases to 38.8% when
venous Doppler indices become abnormal.
• Clin Perinatol 38 (2011) 103–112
106
Management goals & protocol
• Prevention of stillbirth • Delivery based on an accurate assessment of
fetal versus neonatal risks.• Abnormal venous Doppler indices, mandate
higher testing frequency, up to daily testing.• Reversal of DV a wave increases the risk for an
abnormal biophysical profile score within 1 to 8 days.
• Reversal of DV a wave only becomes an independent risk factor for neonatal morbidity and mortality after 27 weeks’ gestation.
• Clin Perinatol 38 (2011) 103–112
107
Tests for fetal lungs maturity
• 1. L/S ratio(>2)• 2.Shake or bubble test• 3.foam stability index• 4.phosphatidyl glycerol• 5.amniotic fluid optical density.• 6.lamellar body count (>30000/micl• 7.amniotic fluid turbidity test• 8. Nile blue sulphatase test
108
COCHRANE REVIEW
• ? Antenatal cardiotocography for fetal assessment (Grivell 2010)
• No clear evidence that antenatal CTG improves perinatal outcome.
• ? Biophysical profile for fetal assessment in high-risk pregnancies (Lalor 2008)Not enough evidence to support use of biophysical profile for assessing fetal wellbeing in high-risk pregnancies
109
• Fetal and umbilical Doppler ultrasound in high-risk pregnancies (Alfirevic 2010)Doppler ultrasound in high-risk pregnancies reduced the risk of perinatal deaths and resulted in less obstetric interventions. The evidence was not of high quality, therefore results should be interpreted with some caution
110
CARRY HOME MESSAGE
• Antenatal fetal assessment should be done with caution to decide time of delivery otherwise can lead to unwarranted interventions .
111
Thankyou