Transcript INTRAUTRINE GROWTH RESTRICTION

INTRAUTRINE GROWTH
RESTRICTION
Dr. Miroslawa Bednarek
Diagnosis of symptom
Fetal growth failing (arising from
maternal, placental, or fetal origins)
Birth weight lower than expected in the
suitable gestational week (may be the
variable described as below the 3rd, 5th,
or 10th percentile)
A perinatological definition of fetal IUGR
Dynamic phenomenon defined
the best
A a delay of the growth of the fetus
estimated as a decrease of 25 centiles
in the measure of the abdominal
circumference, according to the
standard curve at the gestational age,
and in subsequent echograhic
evaluations performed at least every 2
weeks.
Classification
Asymmetrical (late onset – around 30 weeks
of pregnancy) – affects abdominal growth
more that the head circumference.
Symmetrical (early – from the beginning of
the second trimester) – proportional lagging
of the head circumference, abdominal
circumference, and long bone growth.
Natural History
The first 16 weeks of pregnancy –
cellular hyperplasia
From 16 to 32 weeks of pregnancy,
both cellular hyperplasia and cellular
hypertrophy occur.
The last weeks, cellular hypertrophy
predominates
Risk factors – fetal :
Chromosomal abnormalities (triploidy,
trisomy 13 and 18)
Structural malformations (especially
cardiac malformations)
Fetal infections (TORCH, parvovirus
B19, syphilis, listeriosis)
Risk factors – placental :
Abnormalities of the placentation
(reduction of number of thin-walled,
distended uteroplacental vessels)
Acute atherosis
Obliteration of small muscular arteries
of the tertiary villi
Confined placental mosaicism
Chorioangioma
Risk factors – maternal :
Low socioeconomic status
Chronic maternal under nutrition
Malnutrition (anorexia nervosa, bulimia)
Cardiovascular diseases (cardiac
failures, hypertension, pre-eclampsia)
Gastroenteric diseases (chronic
enteritis, malabsorption diseases)
Risk factors – maternal :
Pulmonary diseases (CF, asthma,
respiratory failure)
Renal diseases
Anemia
Alcohol and drug abuse, smoking
Uterine abnormalities (fibroids, uterine
malformations)
Clinical features :
Clinical examination (symphyseal –
fundal distance)
Diagnostic ultrasound (BPD, FL, AC,
EFW) – serial measurements
AFI – amniotic fluid index
Maturity of the placenta – stages
according to Grannum
Doppler examination
Uterine arteries – approximately 25% of
women with unilateral persistant notch and
50% of those with bilateral notch at 24 weeks
of pgregnancy will have an IUGR fetus,
develop pre-eclampsia, or experience both
(sensitivity 82% and specificity of 38%)
Umbilical arteries – affected fetuses show a
reduced blood flow pattern during diastole
Fetal compromise
Gradually increasing resistance to blood
flow in umbilical arteries
End diastolic component may disappear
or may reverse
Redistribution of blood flow occurs
Brain, heart and adrenal glands are
preferentially perfused
MCA blood flow increases
Brain Sparing Phenomenon
Cerebroplacental ratio is below 2 SD
Prior to abnormal CTG recordings about
a couple days to 2 weeks
Associated with fetal hypoxia
When resistance in MCA begins to rise –
cerebral edema occurs
Utero-placental insufficiency
during pregnancy
Diagnosis and management
During pregnancy, fetus depends
on the placenta and umbilical
vessels for transport of oxygen
and nutrients from maternal
blood, and for excretion of carbon
dioxide and products of
metabolism
During pregnancy and labor,
fetus may be at risk of
damage or death from acute
or chronic utero-placental
insufficiency.
Acute placental failure may result
from placental separation by
hemorrhage (abruptio placentae)
or it may come at the end of a
phase of gradually declining
placental efficiency.
Chronic restriction of maternal
blood flow through the
placenta can have a serious
effect upon fetal growth and
development.
Medical History :
Pregnancy induced hypertension
Maternal diseases (DM; severe anemia; renal,
intestinal, cardiac and lung failures;
malnutrition)
Infections in pregnancy
Multiple pregnancies
Some drugs
Addictions (smoking, alcohol, drug abuse)
Placental pathology (placental infarction, fetal
stem artery thrombosis, antepartum,
hemorrhage)
Tests of placental function :
Maternal weight
Uterine growth – fundal height
Fetal body movements
Fetal growth – obtained by ultrasound
Fetal activity – biophysical profile, non-stress
test (CTG)
Color doppler studies
Placental biochemical tests
Maternal weight
Should normally increase by about 0.5 kg
weekly after the first trimester (provided that
the patient is not dieting or vomiting and has
no other disorder causing malnutrition)
Components of this weight gain include: the
fetus, plcenta, liquid, uterus, breasts and fat
store. Additionally there is the increase in
blood volume and ECF.
These changes depend directly on placental
function, or indirectly by the hormone
production
Uterine growth
Simple measurements of the height of the
fundus of uterus in relation to the symphysis
pubis and umbilicus (eg. in 16th week of
gestation – midpoint between pubic
symphysis and the umbilicus; at 24th week –
umbilical level)
Fundal height should increase by about 1 cm
weekly from the 16th week of pregnancy, and
with an average sized fetus, should equal the
number of weeks of gestation plus or minus
2cm
Fetal body movements
The most important indication of placental
function is the well being of the fetus
The oldest and simplest method of evaluation
of the fetal well being is “kick count”
Mother is asked to note how frequently the
fetus moves in a gives period of time,
perhaps in 30 minutes
Alternatively, she can be asked to note how
long it takes for the fetus to move 10 times
Fetal growth
Dating a pregnancy
Serial measurements obtained with
ultrasound
BPD, AC, HC/AC, FL, EFW
Centers of ossification in long bones –
to confirm fetal maturity
Detecting congenital abnormality
Fetal activity
Continuous record of FHR over a period of 30
minutes or more – so called NST (non stress
test). It includes recording of changes in FHR
variability (from beat to beat) in association
with fetal movements and uterine
contractions – cardiotocography (CTG)
Biophysical profile – a score based on real
time ultrasound observation of fetal
breathing, gross body movements, tone and
amniotic fluid volume
Stress test
In a case of doubtful or suspicious
results of non stress test
Contraction stress test – CST
Oxitocin challenge test – OCT
Fetal acoustic stimulation test – FAST
Color Doppler examination
Reflection of ultrasound waves from the wave
produced by the pulse of blood moving along
a blood vessel is detected and compared with
the energy output of the source
This provides a measure of the speed of
passage of the pulse wave and appears as a
typical shape of blood waveform
Seems to be the most useful tool in prediction
of chronic fetal hypoxia
Biochemical markers of
placental function
Evaluation of functional activity of the
placenta by measuring one or more of its
hormone or enzymes products in maternal
blood or urine
Excretion of estriol in the maternal urine
during 24 hour period gives an indication of
placental function, isolated observations are
of little value, but related observations may
show an obvious trend
Other tests: serum levels of placental
lactogen and of heat stable alkaline
phosphatase