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ASSESSMENT OF FETAL WELLBEING. Max Brinsmead PhD FRANZCOG March 2013. The fetus is unique because. He or she cannot signal health by way of history We can only examine through his or her mother Non-invasive evaluation includes... Documentation of size and growth
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ASSESSMENT OF FETAL WELLBEING Max Brinsmead PhD FRANZCOG March 2013
The fetus is unique because... • He or she cannot signal health by way of history • We can only examine through his or her mother • Non-invasive evaluation includes... • Documentation of size and growth • Fetal movements & reaction to stimuli • Fetal heart rate studies using CTG • Amniotic fluid volume study • Looking at placental morphology by ultrasound • Study of blood flow in various fetal and maternal vessels – Doppler studies • Placental endocrine studies in maternal blood and urine
Pregnancies can be divided into those that are High or Low Risk of Fetal Compromise/Death • High risk pregnancies include those that... • Occur with conditions known to impair feto-placental function e.g. Maternal hypertensive conditions, Auto immune disease • Depart from normal growth on clinical assessment i.e. “Too big” or “Too small” • There is a poor obstetric history • Multiple pregnancy • Occur with multiple risk factors e.g. Low social class, ethnic risk, smoking or other drug use etc
Umbilical Artery Doppler Study • Upper panel represents peak (systolic) and trough (diastolic) flow often expressed as S/D ratio • Lower panel is constant flow through a uterine vein • UA Doppler reflects downstream placental resistance • Is the 1st change to occur with placental disease
Abnormal UA Doppler Flows • When flow ceases in the diastolic phase (AEDF) the S/D ratio is very high (∞) • Flow may even reverse in the diastolic phase (RDF) as shown opposite
Uterine Artery Dopplers… • Are of limited use when… • The fetus is very premature (<30 weeks) • Pregnancy is prolonged (>40 weeks) • It is a low risk pregnancy • 5% will be high but normal • Are useful in High Risk Pregnancies • May be used to prolong pregnancy with immature fetus and apparent IUGR • Have a high negative predictive value for fetal death • Will change 4 – 7 days before other changes in fetal wellbeing e.g. Biophysical Profile
Other Pregnancy Doppler Studies • Fetal Middle Cerebral Artery • Resistance falls as brain-sparing IUGR begins • Strong correlation with fetal HB • Of particular use in monitoring intrauterine haemolysis • Fetal DuctusVenosus • Resistance rises as the placenta deteriorates • Maternal Uterine Arteries • Increased resistance with bilateral notching at 12 – 24w predicts early (but not late) onset pre eclampsia with ≈ 60% sensitivity
Fetal Biophysical Profile • Ultrasound for… • Fetal Breathing • Fetal Movements • Fetal Tone • Amniotic Fluid Volume • Non Stress CTG • Looking at fetal heart short term variability and accelerations • Assigns a score of 0,1,2 to each of these five measures as with the Apgar Score • Scores ≤ 6 are abnormal