Neonatology - Prematurity Flashcards
How is prematurity defined?
Extreme preterm
Under 28 weeks
Very preterm
28-32 weeks
Moderate to late preterm
32-37 weeks
What is prematurity of the new-born associated with?
- Social deprivation
- Smoking
- Alcohol
- Drugs
- Overweight or underweight mother
- Maternal co-morbidities
- Twins
- History of prematurity
How is prematurity managed before birth?
Each additional week of gestation has a dramatically improved prognosis
In women with a history or preterm birth or USS showing cervical length of 25mm or less before 24 weeks
Birth can be delayed by
Prophylactic vaginal progesterone
Prophylactic cervical cerclage
How does prophylactic vaginal progesterone work?
Progesterone suppository in vagina
Discourages labour
How does prophylactic cervical cerclage work?
Suture in the cervix to hold it closed
If preterm labour is suspected or confirmed what can be done to improve outcomes?
Tocolysis with nifedipine
CCB that suppresses labour
Maternal corticosteroids
Offered before 35 weeks to reduce neonatal morbidity and mortality
IV Magnesium sulphate
Offered before 34 weeks to protect baby’s brain
Delayed cord clamping or cord milking
Increasing circulating blood volume and Hb in baby
What issues in early life can arise with prematurity in the new-born?
- Respiratory distress syndrome
- Hypothermia
- Hypogylcaemia
- Poor feeding
- Apnoea and bradycardia
- Jaundice
- Intraventricular haemorrhage
- Retinopathy of prematurity
- Necrotising enterocolitis
- Immature immune system and infection
What are the long-term effects of prematurity?
Chronic lung disease of prematurity
Learning and behavioural difficulties
Susceptibility to infections
Hearing and visual impairment
Cerebral palsy
What is apnoea?
Breathing stops spontaneously for more than 20 seconds
or
Shorter periods with oxygen desaturation or bradycardia
What is apnoea often accompanied by?
Period of bradycardia
Who is most commonly affected by apnoea?
Premature neonates
Almost all babies less than 28 weeks
Less common with increased gestational age
What causes apnoea?
Immaturity of the autonomic nervous system, more immature in premature babies
What is apnoea commonly a sign of?
Developing illness e.g.
- Infection
- Anaemia
- Airway obstruction
- CNS pathology
- GO reflux
- Neonatal abstinence syndrome
How is apnoea managed?
Neonatal units - apnoea monitors for prem babies
Tactile stimulation - used to prompt baby to restart breathing
IV caffeine - can be used to prevent apnoea and bradycardia in babies with recurrent episodes
Apnoea settles as baby grows and develops
When babies typically affected by retinopathy of prematurity?
Typically babies under 32 weeks and low weight babies
Why is screening for retinopathy of prematurity so important?
Treatment can prevent blindness
Abnormal development of blood vessels in the retina can lead to:
- Scarring
- Retinal detachment
- Blindness
What is the pathophysiology of retinopathy of prematurity?
Retinal blood vessel development starts at 16 weeks, complete by 37-40 weeks gestation
Vessels grow from middle of the retina to the outer area
Vessel formation stimulated by hypoxia, this is normal during pregnancy
If the retina has higher concentrations in a prem baby with supplementary oxygen, stimulant for normal blood vessel development is removed
In hypoxic environments, the retina responds by producing excessive blood vessels (neovascularisation) as well as scar tissue
Abnormal blood vessels can regress and leave retina without a blood supply
Scar tissue can cause retinal detachment
How is the retina divided into zones?
Zone 1
Optic nerve
Macula
Zone 2
Edge of zone 1 to ora serrata
Zone 3
Outside the ora serrata
What is the ora serrata?
Pigmented border between the retina and ciliary body
How are the retinal areas described?
As a clock face
e.g. Disease from 3 to 5 o’clock
How are stages of disease described in the retina?
Stage 1(slight abnormal vessel growth)
to
Stage 5 (complete retinal detachment)
What is plus disease?
Additional findings e.g. tortuous vessels and hazy vitreous humour
How is screening for retinopathy of prematurity done?
Babies before 32 weeks or under 1.5kg should be screened for ROP
- 30-31 weeks gestational age in babies before 27 weeks
- 4-5 weeks of age in babies born after 27 weeks
How often should screening occur?
At least every 2 weeks
Can stop when retinal vessels enter zone 3, usually at around 36 weeks gestation
