Book of Medical Disorders in Pregnancy - Tintash

Fig 9.2: Shows amniocentesis under
Acceleration of fetal growth for non
hydropic fetuses that often are growth
retarded.
Optical
density
0.287
0.083
0.204
Wave length mu
Optical density of 450
mu peak
Zone III
Zone II
Zone I
Maturity Weeks
Zone I:
When the optical density of the
amniotic fluid analyzed at 28 to 31
weeks was noted in this zone, the fetus
was unaffected or may have mild
hemolytic disease, Liley advised repeat
taps in two to three weeks. The baby
may be Rhesus positive.
Zone II: This is intermediate zone and
the prognostic value of this zone is not
so clear cut. Repeat taps should be
128
performed to determine the trend. This is
zone.
Intrauterine transfusion - When the
amniotic fluid analysis shows the disease
in upper zone II or zone III this suggest
that death of the fetus is likely to occur
in the near future. This is particularly so
if the trend in the repeat tests is rising.
The ideal time for carrying out intrauterine
transfusion is around 23 to 24 weeks
of pregnancy. To carry out this
procedure about 20 ml of renograffin is
injected in the amniotic sac and the fetal
position and location are determined by
biplane fluoroscope. If the fetus is face
up or lateral the procedure is carried but
when the face is down, the procedure is
post-poned due to difficulty in approaching
the peritoneal cavity of the fetus.
A 15 gauge Tuohy's needle is
inserted through the mother's abdominal
wall into the peritoneal cavity of the
fetus and its position is determined by
injecting a small amount of Renografin,
a plastic catheter is passed through this
needle and the needle is then removed.
Group ''0'' rhesus negative blood is used
for transfusion, packed cells are
preferred and about 110 ml. of cells are
given at 30 weeks and 10 ml are added
for every additional week. The same
amount is reduced for every week less
than 30. The total amount is transfused
slowly over a period of one hour. Nearly
70% of the cells transfused are absorbed
into the circulation over a period of six
days. The absorption takes place via the
diaphragmatic lymphatics.
Prenatal management of Rhesus
disease: Early induction combined with
exchange transfusion postnatal is treatment
of choice in mild to mod-erately
affected babies and can save many lives.