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USS FEATURES OF IUGR

AND MACROSOMIA.

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IUGR Various conventional and Doppler ultrasonographic

criteria have been proposed for diagnosing IUGR.

Proposed conventional criteria include estimated fetal

weight below the tenth percentile for gestational age.

Elevated ratio of femur length to abdominal circumference

Elevated ratio of head circumference to abdominalcircumference

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Ratio of FL/AC after 20wks GA of 0.21-0.24 is

considered appropriate for GA.

FL/AC less than 0.21 is considered as macrosomia.

FL/AC greater than 0.24 is considered as

asynmetrical IUGR.

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Doppler criteria include elevated ratio of systolic: diastolic

blood flow velocity in the umbilical artery or in the uterine

artery.

No single criterion however, has a sufficiently high

positive predictive value for IUGR to permit a confident

exclusion of IUGR

Diagnosis or exclusion of IUGR can best be achieved by

the combined use of three parameters: estimated fetal

weight, amniotic fluid volume and maternal B.P

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Intrauterine growth retarded

fetus with absent end-

diastolic flow in the fetalumbilical artery.

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Low etimated fetal birth weight, oligohydraminousand high maternal B.P are pointers towards IUGR.

After extrinsic causes of IUGR,like smoking,alcoholism in the mother, DM and HBP have beenexcluded ; USS should attempt to exclude intrinsic

causes. Intrinsic causes includes aneuploidy Particular

attention should be paid to the fetal hands andtone

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Overlapping fingers or strangely postured

hands in a small fetus should immediately

elicit a concern for trisomy.

isolated fetal anomalies can cause IUGR.

Anything that disrupts the fetal abdomen leads

to apparent IUGR because the abdominalcircumference is altered Examples are

gastrochisis and omphalocele.

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Fetal macrosomia. Defined as estimated fetal birth weight greater than

4000gm.

Various methods have been developed to achieveaccurate weight estimates of the average-sized

fetus.

Unfortunately, there is no one excellent way ofprecisely predicting macrosomia. The problem lies in

the fact that the best ultrasound estimation of weight

can be as much 10% discrepant of the actual weight.

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Extrinsic causes like diabetes in the mother,and

familial tendencies must be bore in mind.Some

genetic causes includes

Beckwith-Wiedemann syndrome usually is a

sporadic abnormality. It is seen with

macroglossia and occasionally umbilicalhernia, which may appear on ultrasound as a

small omphalocele.

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Marshall-Smith syndrome is a sporadic disease in

which markedly accelerated skeletal maturation

results in a long, relatively thin newborn.Anoverestimation of weight is made because the head

and femur are so much larger than anticipated.

Sotos' syndrome is associated with profound

macrocephaly and mild dilation of the cerebralventricles, but there is no consistent pattern of brain

malformation. The hands and feet are also very large

for gestational age.

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The physician should be aware of these

syndromes and search for the associated

anomalies.

Above all, the physician should always look at

the parents when assessing a fetus with

macrocephaly or isolated large hands or feet.Often, large size is simply an expression of

familial propensity.