L2: Fetal Evaluation Flashcards
Another Name of Fetal Evaluation
Fetal Survaillence
Methods of Fetal Evaluation
A) Determination of fetal age.
B) Determination of fetal maturity.
C) Evaluation of fetal wellbeing.
D) Prenatal diagnosis of congenital anomalies.
Duration of Normal Pregnancy
Determination of GA
- Methods
- Hx
- Ex
- INVx
Determination of GA
- By Hx
Determination of GA by Hx
- Menstruation-delivery interval (Naegele’s rule)
Menstruation-delivery interval (Naegele’s rule)
- Method
Commonest Method
- EDD date of 1st day of LNMP+7 days +9 months.
Menstruation-delivery interval (Naegele’s rule)
- Characters of LMNP
a) Should be of normal characters.
b) Should be preceded by 3 consecutive normal cycles.
c) Shouldn’t be preceded by use of hormonal contraception.
Menstruation-delivery interval (Naegele’s rule)
- Causes of Falacies
a) Maternal forgetting Recent use of COCs.
b) Bleeding in early pregnancy.
c) Irregular menstruation or prepregnancy amenorrhea.
Determination of GA by Hx
- Ovulation-delivery interval
EDD = date of ovulation day - 7 days + 9 months.
Determination of GA by Hx
- Coital-delivery interval (date of single coitus)
EDD = date of single coitus (as in rape) 7 days + 9 months.
Determination of GA by Hx
- Date of embryo transfer (ET)
EDD = date of ET (in ARTs) 7 days + 9 months.
Determination of GA by Hx
- Date of quickening
18-20 weeks in primigravida & 16-18 weeks in multipara.
Determination of GA by Hx
- Date of 1st +ve pregnancy test
Most kits allow urine diagnosis of pregnancy at 4th or 5th weeks after LMP.
Determination of GA by Ex
Determination of GA by Ex
- Fundal Level
Determination of GA by Ex
- Symphysis-fundus height (gravidogram)
Determination of GA by Ex
- McDonald’s formula
Determination of GA by Ex
- Fetal weight (Johnson formula)
- Fetal weight (in gm) = [fundal height (in cm) - n] x 155.
▪ n = 12 if head isn’t engaged & 11 if head is engaged
Determination of GA by Ex
- Measurement of abdominal girth
Using certain tables.
Determination of GA by Ex
- Ballotment
Internal ballottement at 16 weeks & external ballottement at 20 weeks.
Determination of GA by Ex
- Auscultation of FHS
- By Doptone at 10 weeks
- By Pinard’s stethoscope at 20 weeks.
Determination of GA by INVx
Determination of GA by US
- Intro
- Fetal body measurements (fetal biometry) reflect GA & there are curves corresponding to development of each of these measurements throughout pregnancy (fetal growth curves).
Determination of GA by US
- Common Measurments
Determination of GA by US
- GS
At 4 weeks by TVS & 6 weeks by TAS
Determination of GA by US
- CRL
At 5 weeks by TVS & 7 weeks by TAS
Determination of GA by US
- BPD
- At 13 weeks
- it ↑↑from 2.4 cm at 13 weeks to 9.5 cm at term
is more accurate at 20-30 weeks
Determination of GA by US
- FL
- At 14 weeks
- it ↑↑ from 1.5 cm at 14 weeks to 7.8 cm at term
- is more accurate than BPD after 30 weeks
Determination of GA by US
- AC
- More accurate than BPD after 30 weeks
- it is the single most important measurement to
make in late pregnancy - (it reflects fetal size & weight rather than age)
Determination of GA by US
- HC
…
Determination of GA by US
- EFW
- Using > 2 parameters in published formulas.
- True weight is 15-20% above estimated weight.
Measurements used in early pregnancy (up to 12-13 w)
GS diameter & CRL
Measurements used during 2nd & 3d trimesters
BPD, FL, AC, HC & EFW
Accurate GA è uncertain LNMP can be obtained from
a) 1 CRL measurement early in 1st trimester.
b) 2 measurements () 16 & 24 weeks showing linear growth.
Accuracy of ultrasound dating of pregnancy is as follows
a) In 1st trimester: CRL is accurate èin 3-5 days from menstrual dating.
b) In 2d trimester: Measurements are èin 2 weeks from menstrual dating.
c) In 3rd trimester: Measurements are èin 3 weeks from menstrual dating.
Causes of Oversized Uterus
Causes of Causes of Undersized Uterus
Determination of Fetal Maturity
- Importance
A) Before elective TOP to determine fetal prognosis.
B) For performing & standardization of all fetal wellbeing tests.
Determination of Fetal Maturity
- Methods
Determination of Fetal Maturity by Hx & Ex
For determination of fetal age (see above).
Determination of Fetal Maturity by INVx
- US
- X-Ray
- Amniotic Fluid
Determination of Fetal Maturity by INVx
- US
BPD, FL, AC & EFW.
Determination of Fetal Maturity by INVx
- X-Ray
Appearance of ossific centers.
Determination of Fetal Maturity by INVx
- AF
Determination of Fetal Maturity by AF
Determination of Fetal Maturity by AF
- Fetal Lung Maturity
Determination of Fetal Maturity by AF
- Fetal Kidney Maturity
AF creatinine level (levels ≥ 2 mg/dl indicate maturity)
Determination of Fetal Maturity by AF
- Fetal Liver Maturity
AF bilirubin level.
Determination of Fetal Maturity by AF
- Fetal Skin Maturity
Detection of fat cells after staining by Nile blue sulfate.
Types of Evaluation of Fetal Wellbeing (Fetal Wellbeing Tests)
- According to time
- Antepartum
- Intrapartum
Def of Antepartum Evaluation of Fteal Wellbeing
Assessment of in utero fetal condition during pregnancy.
Time of Antepartum Evaluation of Fteal Wellbeing
Started usually at 30 weeks.
Methods of Antepartum Evaluation of Fetal Wellbeing
Methods of Antepartum Evaluation of Fetal Wellbeing
- ClinicalMethods of Antepartum Evaluation of Fetal Wellbeing
- Biophysical
Methods of Antepartum Evaluation of Fetal Wellbeing
- Biochemical
Methods of Antepartum Evaluation of Fetal Wellbeing
- Clinical (Detailed)
Methods of Antepartum Evaluation of Fetal Wellbeing
- Daily fetal movement count (DFMC):
Methods of Antepartum Evaluation of Fetal Wellbeing
- Antepartum FHR monitoring
By using external Doppler machine applied on mother’s abdomen.
Features of FHR tracing
- Baseline Rate
- Variability
- Periodic Changes
Normal Baseline rate of FHR
120-160 bpm
Abnormal Baseline rate of FHR
Abnormal Baseline rate of FHR
- tachycardia
Abnormal Baseline rate of FHR
- Bradycardia
Importance of Variability of FHR
Most clinically significant indicator of fetal status & it is regulated by fetal autonomic nervous system.
Types of Variability of FHR
- Short term variability (beat to beat variability)
- Long term variability (baseline variability)
Types of Variability of FHR
- Short term variability Long term variability (beat to beat variability)
Instantaneous change (of 2-3 beats) in FHR from one beat to next beat
Types of Variability of FHR
- Long term variability (baseline variability)
Oscillation of baseline tracing è amplitude of 5-25 bpm & frequency of 3-5 oscillations/min
Types of Variability of FHR
- Causes of decreased or lost variability
Periodic Changes of FHR
- Acceleration
- Decceleration
Periodic Changes of FHR
- Def of Acceleration
- Transient episodes of ↑↑ FHR è amplitude of ≥ 15 bpm & duration of ≥ 15 seconds.
Periodic Changes of FHR
- Causes of Acceleration
Fetal movement, uterine contractions or partial cord compression.
Periodic Changes of FHR
- Def of Deceleration
- Transient episodes of↓↓ FHR è amplitude of ≥ 15 bpm & duration of ≥ 15 seconds.
Periodic Changes of FHR
- Types of Deceleration
Types & Causes of Deceleration
- Early Deceleration
Types & Causes of Deceleration
- Late Deceleration
Types & Causes of Deceleration
- variable deceleration
Types & Causes of Deceleration
- Prolonged Deceleration
Antepartum Fetal Evaluation
- Doppler US
Antepartum Fetal Evaluation by Doppler US
- Method
abdominally or transvaginally
Antepartum Fetal Evaluation by Doppler US
- Importance
- It demonstrates direction & characteristics of blood flow:
▪ So, it helps in assessment of placental blood flow through measuring Doppler indices in umbilical or uterine arteries.
Antepartum Fetal Evaluation by Doppler US
- Most Important Index
Most important Doppler index is:
▪ S/D ratio (systolic/ diastolic velocity ratio).
Antepartum Fetal Evaluation by Doppler US
- First Abnormality to appear
Umbilical artery Doppler abnormalities are 1st to appear:
▪ So, it is logic to use Doppler as the main screening tool
Antepartum Fetal Evaluation by Doppler US
- Results in defective placental flow (as in PIH)
In defective placental flow (as in PIH):
▪ There is ↑↑umbilical artery S/D ratio (normally = 3 at 30 weeks) & in severe cases, there is absent or reversed diastolic flow
Antepartum Fetal Evaluation
- Amnioscopy
Visualization of amniotic cavity through intact membranes when cervix is sufficiently dilated to diagnose meconium stained liquor.
Antepartum Fetal Evaluation
- NST & CST
Most commonly used test for fetal wellbeing
NST
Another name of CST
Named also oxytocin challenge test (OCT)
Def of NST & CST
Principle of NST & CST
Indications of NST & CST
Time of NST & CST
Technique of NST & CST
Interpretation of NST & CST
Frequency of NST & CST
Advantages of NST & CST
Disadvantages of NST & CST
Vibroacoustic stimulation test (VAST)
By using about 80 db sound probe as an
alternative to fetal movements in NST (at this
db, it isn’t a stress test).
CI of CST
→ Previous uterine scar (as previous CS).
→ Placenta previa.
→ PROM.
→ Multifetal pregnancy
→ Threatened preterm labor
→ history of preterm labor.
Antepartum fetal Evaluation
- Biophysical profile (BPP)
Antepartum fetal Evaluation by BPP
Antepartum fetal Evaluation by BPP
- Def
- Scoring system for certain fetal biophysical activities that help in assessment of in utero fetal condition.
Antepartum fetal Evaluation by BPP
- Time
Usually started at 32-34 weeks.
Antepartum fetal Evaluation by BPP
- Technique
Antepartum fetal Evaluation by BPP
- Interpretation
Antepartum fetal Evaluation by BPP
- Advantages
a) Non invasive
b) safe
c) easy to perform.
d) Can be used for assessment of wellbeing of twins.
e) Low false -ve results.
Antepartum fetal Evaluation by BPP
- Disadvantages
Antepartum fetal Evaluation by BPP
- Modified Additions
Antepartum fetal Evaluation
- Biochemical Assessment
Def of Intrapartum Evaluation of Fetal Wellbeing
Assessment of in utero fetal condition during labor.
Time of Intrapartum Evaluation of Fetal Wellbeing
Started whenever labor starts.
Methods of Intrapartum Evaluation of Fetal Wellbeing
- Clinical
- Biophysical
- Biochemical
Methods of Intrapartum Evaluation of Fetal Wellbeing
- Clinical
1) Partogram.
2) Examination of AF.
Methods of Intrapartum Evaluation of Fetal Wellbeing
- Biophysical
Intrapartum Evaluation of Fetal Wellbeing by Biophysical Tests
- Intermittent FHR monitoring
Intrapartum Evaluation of Fetal Wellbeing by Biophysical Tests
- Continuous electronic FHR monitoring
Intrapartum Evaluation of Fetal Wellbeing
- Biochemical Tests