20) Preterm fetus. Small for gestational age. Flashcards
what is SGA (small for gestational age)
it is low birth weight for gestational age
commonly defined as a weight below the 10th percentile for the gestational age
normal weight during term delivery is ?
2500-4200g
foetuses are separated into 3 different categories after birth what are they ?
low birth weight - below 2500g regardless of their gestational age
small for gestational age- foetuses maturation does not correspond to gestational age
premature foetuses - born before 37 weeks of gestation
all IGUR are ?
SGA - birth weight less than 10 percentile of theavergae gestational age
but not all SGA are IUGR - can be due to small mother small baby - they have no increased obstetric or neonatal risk
risks factors for SGA
IUGR
IUGR etiology can be grouped into 4 main categories?
maternal , placental and fetal , and combination of all these (which is the main cause)
maternal causes if IUGR ?
poor nutritional intake , smoking , drug abuse alcoholism renal diseases antiphospholipid syndrome essential hypertension chronic renal disease eclampsia / preeclampsia
advanced diabetes with vascular
involvement
narrow pelvis
what is antiphospholipid syndrome?
autoantibody production
provoking blood clots - in placenta or uterus
diagnosis requires one clinical event such as thrombosis / pregnancy complication
and two - antibody blood testing - conforming the presence of lupus anticoagulant or anti b2 glycoprotein -1
treatment for antiphospholipid syndrome?
heparin - safe in pregnancy
placental causes of IUGR ?
vilamentous cord insertion cord knots cord prolapse bilobed placenta placental abruption reduced placental size
fetal causes causes of IUGR ?
intrauterine infections - listeriosis TORCH
toxoplasmosis , cytomegalovirus herpes
congenital anomalies - chromosomal abnormalities
what are the different types of clinical appearances of IUGR ?
symmetrical and asymetrical
what is symmetrical IUGR ?
both the body, length and the head growth is inadequate
ponderal index
birth weight / higher cm3 = >2 symmetrical IUGR
poor prognosis
symmetrical IUGR caused by ?
occurring very early in pregnancy
intrauterine infections - TORCH
and congenital fetal anomalies
pathological process is intrinsic to the fetus and involves all organs
what is asymmetrical IUGR ?
head is spared and larger than the abdomen
ponderal index
birth weight / height = <2
(>2.5 aga)
uncomplicated prognosis
when does asymmetrical IUGR occur ?
and what causes it ?
late in pregnancy
maternal diseases / placental and cord problems - reducing uteroplacental blood flow
diagnosis of IUGR
fundal height is 3cm below according to what the gestational age should be
maternal weight stationary and sometimes falling in second term
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US - BIOPHYSICAL
gestational age first determined
4) head to abdominal circumference ratio
In a normally growing fetus the HC/AC ratio exceeds 1.0 before 32 weeks. It is approximately 1.0 at 32 to 34 weeks. After 34 weeks, it falls below 1.0.
. In symmetric IUGR, both the HC and AC are reduced.
(asymmetrical HC larger) hc:ac >1
5) Femur length (FL) is not affected in asymmetric IUGR. The FL/AC ratio is 22 at all gestational ages from 21 weeks to term. FL/AC ratio greater than 23.5 suggests IUGR
abdominal crcumference <10 percentile
7) amniotic fluid volume
reduction - correlates with asymmetrical
if single deepest pocket <1cm = IUGR
amniotic fluid index - measuring the largest pockets of fluid found in each of the four quadrant
AFI <5cm = oligohydroamnios
8) fetal weight CALculation formula
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9) umbilical and uterine artery , MCA artery doppler flow study
Reduced or absent or reversed end diastolic velocity (AREDV) in the umbilical artery indicates fetal jeopardy
Middle cerebral artery (MCA): Increased diastolic velocity (brain sparing effect) is observed in a compromised fetus.
aberrant middle cerebral artery to umbilical artery doppler pulsate index
clinical management of IUGR antenatal ?
once fetus has been declared having decreased growth - attention to modification of environmental and social factor that can be changed
Adequate bedrest, especially in left lateral position;
extra calories per day are to be taken;
Maternal hyperoxygenation
these patients should be electronically monitored for any signs of fetal distress at all times - NST , biophysical profiling, kick count , amniotic fluid vol
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Pregnancy ≥ 37 weeks: Delivery should be done.
for cases of severe IUGR with strong US evidence of it -
delivery indicated at usually 34-37wks or gestational age as soon as the lung has reached its maturity .
corticosteroids given to speed it.
Delivery done at 34 gestation in cases of FGR with additional risk factors for adverse perinatal outcome= Preeclampsia, oligohydramnios
if deliver has to be done before 32 weeks, magnesium sulfate should be given
for fetal and neonatal neuroprotection
C section is preferred because its has no tolerance to asphyxia
or
Low rupture of the membranes followed by oxytocin is employed in cases such as pregnancy beyond 34 weeks with favorable cervix and the head is deep in the pelvis.
clinical management of neonate with IUGR ?
after birth the new born should be checked to rule out any :
infections
congenital anomalies
chromosome abnormality - trisomy 18
blood gas analysis
monitoring of blood glucose levels because the fetus does not have adequate hepatic glycogen
polycythmia - Polycythemia may occur when SGA fetuses experience chronic mild hypoxia caused by placental insufficiency. Erythropoietin release is increased
all SGA babies should be watched for signs of Failure-to-
thrive
endocrinologist should be consulted. Some cases warrant growth hormone therapy
Hypoglycemia complication is common in which type of SGA
asymmetrical SGA babies because their larger brains burn calories at a faster rate than their usually limited fat stores hold
most asymmetrical SGA catch up their growth in ?
the first two years of life and have a normal adult height
what happens to infants infants who are significantly small due to illness of the mother
do not reach a normal height as compared to other
what is the morphology of a baby in SGA?
dry and wrinkled skin because of less subcutaneous fat,
scaphoid abdomen,
thin meconium stained vernix caseosa
thin umbilical cord.
Pinna of ear has cartilaginous ridges.
Plantar creases are well defined
All these give the baby an “old-man look”.
what are the complication in SGA ?
Asphyxia,
bronchopulmonary dysplasia and RDS.
Hypoglycemia
Meconium aspiration syndrome
hypothermia
how do we know if a baby is Appropriate for Gestational Age
Birth weight lies between the 10th and 90th percentiles for gestational age
how do we know if it is large for gestational age ?
s birth weight above the 90th percentile for gestational age
what is the definition of a preterm baby ?
baby born before 37 completed weeks of gestation
usually weigh 2500 g or less
length is usually less than 44 cm
what is the classification for preterm birth according to gestational age
full term - 39-40weels
early term - 37-38 weeks
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moderate to late preterm - 32wks to 36 weeks and 6
very preterm -28 to 31 weeks and 6 days weeks
extremely preterm less than 28 weeks
VIABLE GESTATIONAL AGE -24
anatomically what is the morphology of a preterm baby ?
The head circumference disproportionately exceeds that of the chest
abdomen relatively large
Pinnae of ears are soft and flat.
The eyes are kept closed
skin is thin, wrinkly , red and shiny, due to lack of subcutaneous fat
lack of lanugo
Muscle tone is poor.
Plantar deep creases are not visible before 34 weeks.
The testicles are undescended;
small labia major and prominent labia minora and clitorios prominent
what is the prognosis of preterm baby ?
A baby weighing more than 1500 g is most likely (95%) to survive
ADHD
management of preterm baby /
warm incubators were temp and
humidification to counter the water loss is controlled
ET and mechanical ventilation with
or cpap
pulse oximeter
iv fluid and electrolytes
sterility kept for infections
and prophylactic antibiotics
early feeding
through tube / pipette or spoon / bottle / IV
iv started <1200g and less than 30 weeks
1200-1800 - tube feeding
> 1800 (>34wks) breast
favourable sign of progress in preterm baby
The color of the skin remains pink all the time.
(2) Smooth and regular breathing.
(3) Increasing vigor evidenced by—movements of the limbs and cry.
(4) Progressive gain in weight
