ASSESSMENT OF FETAL WELLBEING

Max Brinsmead MB BS PhDMay 2015

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

Umbilical Artery Doppler changes with Gestation

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 Ductus Venosus 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

Uterine Artery Doppler

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

Fetal Biophysical Profile (Manning)

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