Preterm Infants Flashcards
What is the definition of preterm?
A birth that occurs before 37 weeks of completed gestation
What is the definition of term?
A birth between 37-42 weeks of gestation
What is the definition of post-term?
A birth that occurs after 42 completed weeks of gestation
What does post-date mean?
A birth that occurs after the expected date of delivery
What time period does foetal loss encompass?
Less than 22 weeks gestation
What are the different classes of preterm births?
Extremely preterm = 23-27 weeks gestation
Very preterm = 23-31 weeks gestation
What public health intervention caused a fall in the preterm birth rates?
The smoking ban = caused decline of 10%
How many women in Scotland smoke during their pregnancy?
1 in 12 = of these women, 10% start smoking in the later stages of pregnancy
When do over half of childhood deaths occur?
In the first year of life = strong association with preterm birth and low birth weight
What is the association between preterm births and death?
10 times higher risk of death when born before 32 weeks
Why is prematurity rising globally?
Increased maternal age, increased pregnancy-related complications, greater use of infertility treatments, more C-section births before term
What are the most common reasons for preterm births?
Multiple pregnancies = 9 times higher risk of prematurity
Spontaneous preterm labour
Preterm prelabour rupture of membranes
Does having more than one preterm delivery increase the risk of future preterm births?
Yes = >2 preterm deliveries increases risk of another premature baby by 70%
What impact does an abnormally shaped uterus have on preterm birth?
Increases risk by 19%
What are some risk factors for preterm birth?
Interval of less than 6 months between pregnancies
Conceived through IVF
Smoking, alcohol and illicit drugs
Poor nutrition, high BP, diabetes, multiple miscarriages or abortions
What are the main differences between term and preterm babies that need to be considered when managing a preterm baby?
Need more help to stay warm, more fragile lungs, don’t breathe effectively, have fewer reserves, delay cord clamping if possible
How are preterm babies kept warm?
Using a plastic bag under a radiant heater = baby goes in bag feet first
What are common problems in preterm babies?
Temperature control, feeding/nutrition, sepsis, metabolic, ROP, system immaturity/dysfunction
What are some problems caused by system immaturity/dysfunction in preterm babies?
Respiratory distress syndrome (RDS)
Patent ductus arteriosus (PDA)
Intraventricular haemorrhage (IVH)
Necrotising enterocolitis (NEC)
What is low admission temperature a risk factor for?
Neonatal death = hypothermia increases severity of all preterm morbidities
What is mostly responsible for hypothermia in newborns?
More due to lack of knowledge than lack of equipment
Why is thermal regulation ineffective in preterm babies?
Low BMR
Minimal muscular activity
Subcutaneous fat insulation is negligible
High ratio of surface area to body mass
What does maintaining the temperature of a baby prevent?
Hypoglycaemia and hypoxia
What is the treatment for hypothermia?
Wrap/bags, skin to skin contact, transwarmer mattress, prewarmed incubator
Why do preterm babies have an increased risk of nutritional compromise?
Limited nutrient reserves, gut immaturity, immature metabolic pathways, increased nutrient demands
How much must the weight of a preterm baby be increased by?
Must increase by 7 times in 14-16 weeks
How may babies be supported nutritionally?
Breastmilk is best
Total parenteral nutrition may be used
Formula feeding rarely used and isn’t advocated
What must any breastmilk donor undergo?
Viral screening
How does protein energy malnutrition arise in babies being fed using formula?
Demand of baby increases as it grows but parents often don’t increase the amount of formula they are buying
What are the two types of neonatal sepsis?
Early onset (EOS) = mainly due to bacteria before and during delivery Late onset (LOS) = acquired after delivery (nosocomial or community sources)
What organisms are implicated in neonatal sepsis?
Early onset = Group B strep, gram negatives (lower GI)
Late onset = gram negatives, coagulase negative staph, staph aureus
Why are preterm babies at risk of neonatal sepsis?
Immature immune system, intensive care environment, indwelling tubes and lines
How is neonatal sepsis managed?
Prevention, hand washing, infection screening, antibiotics, supportive measures
What are some respiratory complications associated with preterm birth?
Respiratory distress syndrome, apnoea of prematurity, bronchopulmonary dysplasia
What causes respiratory distress syndrome?
Primary pathology = surfactant deficiency, structural immaturity
Secondary pathology = may be due to intubation
What is respiratory distress syndrome?
Hyaline membrane disease due to lack of surfactant
How does alveolar damage occur in respiratory distress syndrome?
Formation of exudate from leaky capillaries, inflammation, repair
Is respiratory distress syndrome common in preterm babies?
Yes = occurs in 75% of babies born before 29 weeks
What are the clinical features of respiratory distress syndrome?
Tachypnoea, grunting, intercostal recessions, nasal flaring, cyanosis, respiratory distress, worsens over minutes to hours
What is the natural history of respiratory distress syndrome?
Gradual worsening over 2-4 days then gradual improvement
How is respiratory distress syndrome treated?
Maternal steroid, surfactant replacement, ventilation
Why is blood shunted away from the lungs by the ductus arteriosus in normal foetal circulation?
Blood mostly bypasses the lungs in order to supply the other developing organs (e.g the brain)
What does a patent ductus arteriosus cause?
It increases the workload of the heart
How are intraventricular haemorrhages graded?
From 1 to 4
What occurs is grade 1 and 2 intraventricular haemorrhages?
Neurodevelopmental delay up to 20%, mortality is 10%
What occurs in grade 3 and 4 intraventricular haemorrhages?
Neurodevelopmental delay up to 80%, mortality is 50%
Why does necrotising enterocolitis occur?
Gut of baby is not ready to process and digest milk = gut bacteria translocates across broken barrier into bloodstream causing sepsis
What babies are more commonly affected by necrotising enterocolitis?
Usually extremely preterm babies
What are some features of retinopathy of prematurity?
Usually presents 6-8 weeks after delivery, common in babies born before 32 weeks, screened for every 4 weeks after birth
What are some metabolic complications associated with preterm births?
Early = hypoglycaemia, hyponatraemia Late = osteopenia of prematurity (due to increased demand for minerals for growth)
How much difference does each day make in the survival of extremely preterm babies?
Very important = survival increases by 2% each day
What has the trend been in the survival of preterm babies?
Trend has been increasing since 1998
What two treatments have made the most difference n improving the survival of preterm babies?
Antenatal steroids and surfactant replacements
How common are preterm births?
About 6% of births are preterm
Are the survival rates of preterm babies different depending on gender?
Yes = girls have higher survival rates than boys when born preterm
