Low Birth Weight And Prematurity Flashcards
Low birth weight
Less than 2500g
Very low birth weight
Less than 1500g
Extremely low birth weight
Less than 1000g
Normal weight at term
2500-4200g
Inter uterine growth restriction
Fetus with birth weight <10th percentile of those born at same gestational age and displays signs of chronic hypoxia and failure to thrive
How many standard deviations below population mean is considered growth restricted
2
What does fetal growth depend on
Genetic potential
Substrate supply from placenta
How much weight does the fetus gain a day at 14wks, 20wks, and 33wks
5g
10g
30-35g
At what week does fetal growth rate start to decrease
35
How is symphysiofindal height measured
Pubic symphysis to top of uterus
What affects symphysiofindal height
Fetal size
Amniotic fluid volume
Where is abdominal girth measured
Level of umbilicus
How much does symphysiofindal height increase per day between weeks 14 and 32
1cm
How much does abdominal girth increase per day after 30wks
2.5cm
Which type of IUGR is symmetrical
1
What causes type 1 IUGR
Growth inhibition in early pregnancy - 4-20wks
What causes type 2 IUGR
Restriction of nutrient supply in utero
What is the criteria for type 1 IUGR
All parameter below 10th percentile for gestational age with normal ratio
What can cause growth inhibition in early pregnancy
Genetics
Infection of fetus/amniotic sac
Multiple gestation
Environmental toxins - smoking
What weeks is growth restricted in type 1, type 2, and type 3IUGR
1 - 4-20wks
2 - 28+wks
3 - 20-28wks
What causes brain sparing effect/asymmetry in type 2 IUGR
Redistribution of CO to brain and heart
Effects of Type 3 IUGR
Skeletal shortening
Decr soft tissue mass
What conditions can lead to type 2 IUGR
Maternal HT and pre eclampsia
Renal disease
Vasculopathy
What conditions can lead to type 3 IUGR
Chronic HT
Lupus nephritis
Maternal vascular disease
Which types of IUGR affect hyperplasia and hypertrophy
1 - hyperplasia
2 - hypertrophy
3 - both
What Antepartum, Intrapartum, and neonatal Complications are more common with IUGR
perinatal morbidity, morality, and still birth
Oligohydramnios
Meconium aspiration
Fetal distress
Hypoxic ischaemic encephalopathy
Fetal circulation insufficiency
Temperature regulation difficulty
Hypoglycaemia
Chronic intrauterine hypoxia
Birth/perinatal asphyxia
Retinopathy of prematurity
Hypocalcemia
Polycythemia/hyperviscocity
Low serum ferritin
Pulmonary haemorrhage
Immunodeficiency
Renal dysfunction
Feed intolerance/necrotising enterocolitis
Persistent pulmonary hypertension
Why do babies with IUGR have difficulty regulating temperature
Little brown fat
Small body mass to surface area
Why is Oligohydramnios more common with IUGR
Fetal kidneys not developed
Childhood IUGR complications
Increased mortality from infections and congenital abnormalities
Cerebral palsy
Impaired cognitive performance
Adult IUGR complications
Coronary heart disease
Hypertension
T2 diabetes
Dislipidaemia
Stroke
IUGR diagnosis
Identify at risk mothers
Serial fundal height measurement
Serial abdominal girth measurement
Head circumference
Amniotic fluid volume
Doppler ultrasound - umbilical artery, middle cerebral artery, cerebral/placental ratio
What lag in fundal height suggests IUGR
4wks
6wks = severe IUGR
What ratio between MCA and umbilical artery is normal
Below 1
1.1= brain sparing
IUGR management
Treatment of underlying cause
Bed rest in left lateral position
Maternal oxygen therapy
Delivery
Antenatal steroids
Why are mothers with IUGR on bed rest in left lateral position
Increases uteroplacental blood flow
Main cause of infant deaths
Congenital defects and chromosomal disorders
preterm birth
Born Before 37 weeks
Deficiency of what nutrient increases pre term births
Vitamin D
Peripheral inserted central catheter
IV used for medications and replacing fluids
How is a pre term baby’s airways kept open in an incubator
SIPAP or CPAP
Orogastric tube function in preterm baby
Aid feeding
Remove air from stomach
What causes respiratory distress syndrome
Structural and functional immaturity of lungs - underdeveloped parenchyma and surfactant insufficiency
Why do antenatal steroids decrease respiratory distress syndrome
Stimulate maturation of type 2 pneumocytes to produce surfactant
Intra ventricular haemorrhage
bleeds into ventricles and brain tissue
Periventricular leukomalacia
White matter softens and dies around lateral ventricles leaving fluid filled cysts due to interventricular haemorrhage
What causes retinopathy of prematurity
Abnormal fragile blood vessels grow across retina and leak scarring and detaching retina causing reduced vision or blindness
When in gestation does the eye start developing
Week 16
Why do pre term baby’s have temperature control problems
Large SA:volume
Less subcutaneous and brown fat
Inadequate thermal response
Skin may be thinner and may not be fully keratinised
Poor capillary response
Why might premature babies need Parenteral infusion of fluids, nutrients and vitamins
GI system usually immature and unable to process enteral feeds
Why do pre mature babies have lower energy requirements than term babies
Less activity and movement
Why do premature babies need more protein, calcium, and phosphorus
Muscle and bone growth
Necrotising enterocolitis symptoms
Milk aspirated from stomach
Bile stained vomit
Distended abdomen
Bloody stools
Shock
Distended bowel loops, thickened bowel wall, and intramural gas on x ray
Bowel perforation
What causes necrotising enterocolitis
Bacterial invasion of ischemic bowel wall
What condition is more likely in babies fed cows milk
Necrotising enterocolitis
Necrotising enterocolitis treatment
Stop oral feeding
Broad spectrum antibiotics
Surgery to remove perforated bowel
Why is fluid and electrolyte balance monitored
Prevent dehydration, fluid overload, electrolyte balance, fluid loss
What can fluid overload lead to
Congestive heart failure
Necrotising enterocolitis
Mortality
How is fluid loss through the skin minimised in preterm babies
Humidified incubators
Skin emollients
Why is sodium restricted in pre term babies
Immature Nephrons not equipped to handle large amounts of sodium
Why are premature babies often given iron supplements for 6 months corrected age
Anaemia of prematurity
