Problems of Low Birth Weight + Prematurity Flashcards
Median UK birth weight at term (40 weeks)
3.48kg
Low birthweight
<2500g
Very low birthweight
<1500g
Extremely low birthweight
<1000g
Prematurity
Birth before 37 weeks completed gestation
Problems
Neurodevelopmental sequelae
Small for Gestational Age
Birth weight below 10th/3rd centile for gestation
Complications of foetal growth restriction
Very long term health problems
Fetal Growth Restriction (FGR/IUGR)
Failure to achieve normal rate of foetal growth e.g. from uteroplacental insufficiency or foetal infection
SGA Genetic
Normal small baby
Chromosomal disorders
Inherited disorders
SGA Acquired
Utero-placental insufficiency Congenital infection Smoking Maternal chronic illness (renal, sickle cell disease) Multiple pregnancy
Edwards syndrome
Trisomy 18
Small with congenital abnormalities
Utero-placental insufficiency and Intrauterine growth restriction- DETECTION
May be detected antenatally because of poor growth
Doppler ultrasound of uterine arteries + foetal circulation
Utero-placental insufficiency and Intrauterine growth restriction- Causes
Failure of syncytiotrophoblast invasion of high resistance spinal arteries
Poor placental development with raised resistance in placental vascular bed
SGA baby problems
Temp control- Increased SA/V ratio, reduced adipose tissue insulation, reduced capacity for thermogenesis
Polycythemia- response to foetal hypoxia
Poor nutritional status –> hypoglycaemia
Low blood sugar treated with feeds or IV dextrose
Symptomatic hypoglycaemia –> risk of adverse neuro-developmental outcome
Increased risk necrotising enterocolitis
Hypoglycaemia
Low birth weight baby likely to have reduced glycogen reserves (preterm or inadequate transplacental nutrition)
Risk of hypoglycaemia <2.6mmol/l
Treated with feeds or bolus of dextrose + IV infusion
Symptomatic (lethargy, fits) hypoglycaemia is a RF for adverse neuro-developmental outcome
Barker hypothesis
Low birth weight associated with: Diabetes Hypertension CHD Stroke Chronic Bronchitis
Causes of prematurity
Spontaneous preterm labour
Delivered by an obstetrician
Spontaneous preterm labour
Infection or ruptured membranes
Cervical incompetence
Polyhydramnios
Premature delivery by obstetrician
To save mother (hypertension, haemorrhage)
To save foetus (placental insufficiency)
Preterm baby problems
High risk of heat loss
–> large SA/V ratio, think skin, less adipose tissue, wet at birth, can’t shiver, poor metabolic reserve
Resp Problems of prematurity
Primitive alveolar development Susceptibility to O2 toxicity + barotrauma Surfactant deficiency Lack of respiratory drive Immature immune system Instrumentation of airway
Resp. clinical problems
Resp. distress syndrome
Pneumonia
Apnoea of prematurity
Chronic lung disease of infancy
Surfactant structure
Monolayer of phospholipid molecules at air-liquid interface in alveoli
Mainly consists of DPPC + PG
Stabilised by Surfactant Protein B
Reduces surface tension at the air-fluid interface
Resp. Distress syndrome
Lack of surfactant in premature baby
Diagnosis- clinical, radiological + post-mortem
Tachypnoea, expiratory grunting, recession
Onset within 4h of birth
Prevention of RDS
Ante-natal steroids Avoidance intrauterine hypoxia Prophylactic surfactant treatment Keep warm Avoid acidosis
