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Fetal Health Scan Home > Services We Offer
Fetal Health Scan (26-42 weeks)
The fetal health and wellbeing can be assessed from 26 weeks onwards. However, the scan is ideally done at 30-32 weeks. A general anatomical survey is done to detect structural abnormalities as certain abnormalities such as ventriculomegaly (excess fluid in the brain) may develop at this time.

The growth of the fetus is assessed by measuring the parameters including biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and the femur length (FL). The parameters are plotted on a local fetal growth chart and the fetal weight is estimated (EFW) using a local fetal weight formula. Most problems with growth occur in the third trimester. From the growth charts and EFW, a diagnosis of intra-uterine growth restriction (IUGR) can be made. This is important as IUGR babies have an associated increased risk of mortality. Similarly, it is also possible to diagnose "big babies" or "macrosomia", where the baby has reached beyond the normal growth patterns. This will have implications on the further management of such pregnancies, in particular, to plan how the baby is delivered.

We have realized that it is increasingly important to have growth charts and fetal weight formulae for the local population. It is well known, for example, that Caucasian babies (adapted for most growth charts and fetal weight formulae) are about 300 gm heavier than Asian babies. Therefore, if Caucasian charts (available in most ultrasound machines) are used, the growth assessment will become inaccurate for our local Malaysian women.

Growth Charts for Malaysian women, (Chinese and Malays and the Indian charts), adapted from Dr S Raman's MD thesis (1994) are now available. Measurements of the BPD, FL, HC and AC are plotted on these charts to assess the baby's growth. Dr Jason Lim has also made available a local fetal weight formula for the three cultural groups, to estimate the fetal weight for a particular gestation (adapted from his MD Thesis 2000). This important breakthrough allows local doctors to evaluate the fetal growth patterns and estimate the fetal weight with greater precision.
Measurement or estimation of the amount of amniotic fluid or liquor (using the amniotic fluid index or AFI) surrounding the baby can further assess the baby's well-being or health. Our ultrasound machines are equipped with colour Doppler, which can assess the blood flow in the umbilical cord and also within the fetus itself. With the appropriate interpretation, the doctor can decide when a high-risk baby ought to be delivered.

Oligohydramnios (decreased amniotic fluid) may be associated with IUGR or abnormalities of the fetal kidneys. In the absence of fetal abnormalities, reduced liquor may indicate a "sick" baby with IUGR. It may reflect reduced blood flow to the fetal kidneys and therefore the fetus produces less urine, giving rise to oligohydramnios. For this reason, doctors will request a blood flow study or Doppler examination of the fetus if the liquor is reduced.

Colour Doppler Assessment / Blood flow studies is done to help in the evaluation of fetal well-being and if abnormal may indicate that it is time to deliver a baby. It assesses how much blood goes into the baby and therefore if the resistance is high or less blood flows into the baby, the baby's growth may be affected and the liquor volume reduced.
A diagrammatic demonstration of how the placenta nourishes the baby in the womb. In a situation where there is placenta insufficiency such as in pre-eclampsia, less blood flows (red arrows) through the placenta into the umbilical cord and into the baby. Subsequently less blood flows (red arrows) to the baby's kidneys causing them to produce less urine (blue arrow) and therefore the amniotic fluid is reduced. If less blood flows to the baby, the growth of the baby will eventually be affected thus causing intra-uterine growth restriction (IUGR).
Normal umbilical artery doppler
Abnormal umbilical artery Doppler [end diastolic gap]
Abnormal umbilical artery Doppler [reversal of flow]