Book of Medical Disorders in Pregnancy - Tintash

tract. Normal kidneys can easily be
seeing bilaterally next to the spine.
Observation of the fetal bladder speaks
for functioning kidneys. However, an
extremely distended bladder with or
without hydronephrosis ma suggest
obstruction in the urinary tract. Polycystic
kidneys and solitary cysts have
been reported IV diagnosed by ultrasound.
Although much attention has
been directed toward determining fetal
sex in utero the results are grossly exaggerated
and unconvincing. Some physicians
and clinics use this for cheap
publicity. This unethical and should be
discouraged. Chromosomal analysis of
the fetal cells is the only best method
available for determining sex of the baby
and can be carried out where sound
indication for genetic disorder is present.
Deep vein thrombosis - Ultrasound has
been used to detect the patency of veins
utilizing the Doppler Effect. This can be
used to screen high risk post operative
cases and chronically ill patients who are
bed ridden. This method is a good
screening tool. For definite diagnosis
other methods should be applied.
Secondary post partum hemorrhage -
Ultrasound may help to show the
presence or absence of placental tissue in
the uterus in these cases.
Hazards of ultrasound:
The two major biological effects caused
by ultrasound are thermal change and
cavitation. Ultrasound used for physical
therapy can cause significant heat change
in tissues but conventional diagnostic
equipment works with much less
energy. Cavitation will be caused only if
levels of frequency are above the normal
range.
217
Based on experimental and human data
it seems that diagnostic ultrasound is
harmless to mammalian tissues when
used in the conventional way with a
justified clinical indication. Recent
studies reported in the literature have not
shown any danger of chromosomal
damage in leucocytes of rat cells
bombarded with considerably higher
frequency of ultrasound.
In the past radiography was the main
diagnostic intervention employed in obstetric
patients particularly in pelvimetry
and chest X-ray similarly in emergency
situations X-ray abdomen and IVP were
carried out keeping in view the hazards
of radiation to the fetal gonads and
teratogenic effects on the embryo and
fetus. At present both CT scan and MRI
has become available and is being used
in pelvimetry and other emergency
conditions Unlike Ultrasound scanning
there is definite risk of ionized radiations
when these diagnostic procedures are
employed therefore all precautions must
be taken into consideration to safe guard
both the fetus and mother.
The increasing use of imaging in the
population will inevitably result in an
increase in requests for imaging in
women who are pregnant or lactating.
The objectives of these guidelines are to
review:
Teratogenesis after exposure to
ionizing radiation: Organogenesis
occurs predominantly between 2 and 15
weeks gestation. This is the period when
the fetus is most susceptible to the
teratogenic effects of ionizing radiation,
which include micro-cephaly,
microphthalmia, mental retar-dation,
growth retardation, behavioral defects,
and cataracts.