Neonatology - Prematurity

Question 1

How is prematurity defined?

Answer 1

Extreme preterm
Under 28 weeks

Very preterm
28-32 weeks

Moderate to late preterm
32-37 weeks

Question 2

What is prematurity of the new-born associated with?

Answer 2

• Social deprivation
• Smoking
• Alcohol
• Drugs
• Overweight or underweight mother
• Maternal co-morbidities
• Twins
• History of prematurity

Question 3

How is prematurity managed before birth?

Answer 3

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

Question 4

How does prophylactic vaginal progesterone work?

Answer 4

Progesterone suppository in vagina

Discourages labour

Question 5

How does prophylactic cervical cerclage work?

Answer 5

Suture in the cervix to hold it closed

Question 6

If preterm labour is suspected or confirmed what can be done to improve outcomes?

Answer 6

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

Question 7

What issues in early life can arise with prematurity in the new-born?

Answer 7

• Respiratory distress syndrome
• Hypothermia
• Hypogylcaemia
• Poor feeding
• Apnoea and bradycardia
• Jaundice
• Intraventricular haemorrhage
• Retinopathy of prematurity
• Necrotising enterocolitis
• Immature immune system and infection

Question 8

What are the long-term effects of prematurity?

Answer 8

Chronic lung disease of prematurity
Learning and behavioural difficulties
Susceptibility to infections
Hearing and visual impairment
Cerebral palsy

Question 9

What is apnoea?

Answer 9

Breathing stops spontaneously for more than 20 seconds

or

Shorter periods with oxygen desaturation or bradycardia

Question 10

What is apnoea often accompanied by?

Answer 10

Period of bradycardia

Question 11

Who is most commonly affected by apnoea?

Answer 11

Premature neonates

Almost all babies less than 28 weeks

Less common with increased gestational age

Question 12

What causes apnoea?

Answer 12

Immaturity of the autonomic nervous system, more immature in premature babies

Question 13

What is apnoea commonly a sign of?

Answer 13

Developing illness e.g.
- Infection
- Anaemia
- Airway obstruction
- CNS pathology
- GO reflux
- Neonatal abstinence syndrome

Question 14

How is apnoea managed?

Answer 14

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

Question 15

When babies typically affected by retinopathy of prematurity?

Answer 15

Typically babies under 32 weeks and low weight babies

Question 16

Why is screening for retinopathy of prematurity so important?

Answer 16

Treatment can prevent blindness
Abnormal development of blood vessels in the retina can lead to:
- Scarring
- Retinal detachment
- Blindness

Question 17

What is the pathophysiology of retinopathy of prematurity?

Answer 17

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

Question 18

How is the retina divided into zones?

Answer 18

Zone 1
Optic nerve
Macula

Zone 2
Edge of zone 1 to ora serrata

Zone 3
Outside the ora serrata

Question 19

What is the ora serrata?

Answer 19

Pigmented border between the retina and ciliary body

Question 20

How are the retinal areas described?

Answer 20

As a clock face

e.g. Disease from 3 to 5 o’clock

Question 21

How are stages of disease described in the retina?

Answer 21

Stage 1(slight abnormal vessel growth)
to
Stage 5 (complete retinal detachment)

Question 22

What is plus disease?

Answer 22

Additional findings e.g. tortuous vessels and hazy vitreous humour

Question 23

How is screening for retinopathy of prematurity done?

Answer 23

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

Question 24

How often should screening occur?

Answer 24

At least every 2 weeks

Can stop when retinal vessels enter zone 3, usually at around 36 weeks gestation

Question 25

How is retinal examination done?

Answer 25

All retinal areas need to be visualised

Retinal vessels must be monitored as they developed and looking for plus disease

Question 26

How is ROP treated?

Answer 26

Systematically targeting areas of retina to stop new blood vessels developing

First line
Transpupillary laser photocoagulation - stops and reverses neovascularisation

Second line
Cryotherapy
Injections of intravitreal VEGF inhibitors

Surgery
If retinal detachment occurs