Obstetric Ultrasound has became a very useful tool ever since it was introduced
in the late 1950's. The current equipments used are in "real-time",
in which continuous images of the moving fetus is captured (by the transducer)
and processed on the monitor for display. High frequency sound waves
are emitted from the transducer that comes in contact with the maternal abdomen.
Repetitive ultrasound beams that come out of the transducer are used
to scan the fetus in slices and are reflected back onto the same transducer
for processing. Eventually the information obtained from different
reflections will come together to make the image that appears on the monitor,
and this information can be used to access the fetal heart, gestational age,
size and growth in the fetus.
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| Fetus at 9 weeks |
Fetus at 12-weeks demonstrating presence of the
nasal bone |
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| Shortened humerus in a fetus may be associated
with high risk for Down syndrome |
The nuchal fold could indicate a high risk for
Down syndrome if thickness is increased |