ABNORMALITIES OF FETAL MEMBRANES AND AMNIOTIC FLUID
Abnormalities of fetal membrane
1. staning - is obvious within 1 to 3 hr. after meconium passage if the meconium has passed many days before delivery the staning becomes light green or brown.
-the membrane usually appears diffusely opaque due to neutrophil infiltration.
3. RETROMEMBRANOUS HGE
-the hemorrhage occurred days before delivery. The pigment in the membranes maybe brown or yellow.
1. amnion nodosum - these usually Appears as small nodules on the membrane, seen in pregnancies with oligohydamnios. Microscopy discloses these nodules to be formed of desquamated skin cells
2. Squamous metaplasia -appear as white nodules under
the amnion, not in the surface.
c. Placental insertion
-occurs when the membrane insert into the placental surface in a curved border of folded membranes at the margin.
-this folds elevates the membrane in a White rim above the placental surface, antepartum hemorrhage, preterm delivery, perinatal deaths, and fetal malformation were reported To be increased for pregnancies with this placental type.
2. Marginal Insertion
- more common
-the membrane insert into the lacental discs at its margin
- another variant of this circummaginate occurs when the membrane insert away from the placental edge and extend beyond the vascular plate into a white fibrin at the placental edge.
DISORDERS OF AMNIOTIC FLUID
-early in the second trimester the vol occupied by the fetus is about equal to the vol. of the amniotic fluid.
- The fetus does not appear confined within the uterus seen to move freely in a bath of fluid
-Throughout the 2nd and 3rd trimesters,the vol. of the fetus increase in comparison to the vol. of the fetus , and late pregnancy the amount of fluid , and late in pregnancy the amount of fluid appears small in comparison with the fetus.
-normally, amniotic fluid vol. reaches about 10000 ml by 36 weeks, but decreases thereafter
Sonogram has made objective measure of amniotic lluid possible. Two routinely used objective methods are :
1. measurement of a single vertical (SVP) pocket or fluid
2. calculation of the amniotic fluid index .
-The SVP is obtained by measuring the antero- posterior dimension (depth) of the largest pocket of amniotic fluid void of fetal parts or umbilical cord.
-a pocket measuring 2-8 cm is considered normal.
-The AFI is calculated by dividing the
uterus Into four equal segments and
measuring the largest pocket of fluid
(antero posterior measurement excluding
fetal parts and umbilical cord) in each
quadrant and adding the 4 numbers
- The AFI varies with gestational age, but
as a rule of thumb, the normal AFI falls
between 10 - 24 cm after 30 weeks
-diminished amniotic fluid volume
-severe if AFI is less than 2cm and carries a perenatal mortality 40 - 50 times than that of normal pregnancies.
autopsy findings in these fetuses showed
either bilateral renal agenesis, bilateral
cystic dysplasia, or unilateral agenesis
with dysplasia. a few had minor urinary
for those fetuses who survived,
adhesions, between the amnion and fetal
parts cause serious deformities including
Subjected to pressure from all sides , a fetus assumes a peculiar appearance , musculoskeletal deformities such as clubfoot are observed.
when amniotic fluid is scant, pulmonary
hypoplasia is common. Possible causes
include thoracic compression, lack of
fetal breathing movement which include
lung inflow, and failure to retain amniotic
fluid or increased outflow with impaired
Cause of olygohydramnios
Premature Rapture of Membrane
Placental Insufficiency or Abruption
FETAL GENITOURINARY ANOMALIES
Bilateral Renal Anomalies
Bladder Outlet Obstruction
Posterior Urethral Valves
FETAL CHROMOSOME ANOMALIES INTRAUTERINE GROWTHRESTRICTION PHARMACEUTICAL CAUSES
Prostaglandin Synthetase inhibitors.
Angiotensin-Converting Enzyme Inhibitors.
- Defined as excess of amniotic fluid of more than 2000 ml.
Cause of Polyhydramnios
Idiopathic (60% - 70%)
Fetal Macrosomia ( with or without diabetes
Maternal Diabetes Mellitus
CNS disorder affecting swallowing
Gastrointestinal atresia and Obstruction
Musculoskeletal anomalies affecting