Prematurity, RoP & NEC Flashcards
Define premature birth
<37 weeks gestation
Define:
1) extreme preterm
2) very preterm
3) moderate to late preterm
1) before 28 weeks
2) 28-32 weeks
3) 32 to 37 weeks
What are some identified risk factors for premature delivery?
1) Previous preterm delivery
2) Multiple pregnancy
3) Smoking and illicit drug use in pregnancy
4) Being over or underweight in pregnancy
5) Early pregnancy (within 6 months of previous pregnancy)
6) Problems involving cervix, uterus or placenta:
- infection
- eclampsia
- placental abruption
7) Premature or prelabour rupture of membranes
8) Maternal comorbidities such as diabetes and hypertension
9) Physical injury/trauma
In women with a history of preterm birth or an US demonstrating a cervical length of 25mm or less before 24 weeks gestation, what are the two options of trying to delay birth?
1) Prophylactic vaginal progesterone –> putting a progesterone suppository in the vagina to discourage labour
2) Prophylactic cervical cerclage –> putting a suture in the cervix to hold it closed
Where preterm labour is suspected or confirmed, what are the options for improving the outcomes?
1) Tocolysis with nifedipine
2) Maternal corticosteroids
3) IV Magnesium sulphate
4) Delayed cord clamping or cord milking
What class of drug is nifedipine?
A calcium channel blocker
What is the role of nifedipine in premature labour?
Tocolysis –> Nifedipine is a calcium channel blocker that suppresses labour
Define tocolysis
Tocolytics are medications used to suppress premature labor.
When should maternal steroids be given in premature delivery?
If between 26-34 weeks gestation
Role of steroids in preterm labour?
Reduce incidence of respiratory distress syndrome by stimulating development of lungs.
Role of IV Magnesium sulphate in preterm delivery?
Neuroprotective for baby
Role of delayed cord clamping or cord milking in preterm?
Can increase the circulating blood volume and haemoglobin in the baby
What issues in early life can prematurity lead to?
1) RDS
2) Hypothermia
3) Hypoglycaemia
4) Poor feeding
5) Apnoea and bradycardia
6) Neonatal jaundice
7) Intraventricular haemorrhage
8) Retinopathy of prematurity
9) Necrotising enterocolitis
10) Immature immune system and infection
What long term effects can prematurity have?
1) Chronic lung disease of prematurity (CLDP)
2) Learning and behavioural difficulties
3) Susceptibility to infections, particularly respiratory tract infections
4) Hearing and visual impairment
5) Cerebral palsy
At what gestation age should resuscitation not be performed in premature babies?
<23 weeks
Between 23 and 23+6 weeks then there may be a decision not to start resuscitation in the best interests of the baby, especially if parents have expressed this wish.
Between 24 and 24+6 weeks, resuscitation should be commenced unless the baby is thought to be severely compromised
At what gestation age is it appropriate to resuscitate and start intensive care?
After 25 weks
What respiratory complications may be caused by prematurity?
1) Respiratory distress syndrome
2) Surfactant deficient lung disease
3) Chronic lung disease/ Bronchopulmonary dysplasia
4) Recurrent apnoea
What is retinopathy of prematurity RoP)?
A condition affecting preterm and low birth weight babies.
It is a potentially blinding condition caused by the abnormal development of the blood vessels in the retina can lead to scarring, retinal detachment and blindness.
Treatment can prevent blindness, which is why screening is so important.
What age gestation does RoP typically present?
Babies born <32 weeks gestation
At what gestational age does retinal blood vessel development start?
Around 16 weeks, is complete by 37 – 40 weeks gestation.
What is retinal blood vessel development stimulated by?
Hypoxia (which is a normal condition in the retina during pregnancy).
How does prematurity cause RoP?
1) When the retina is exposed to higher oxygen concentrations in a preterm baby, particularly with supplementary oxygen during medical care, the stimulant for normal blood vessel development is removed.
2) When the hypoxic environment recurs, the retina responds by producing excessive blood vessels (neovascularisation), as well as scar tissue.
3) These abnormal blood vessels may regress and leave the retina without a blood supply.
4) The scar tissue may cause retinal detachment.
What are the 3 key risk factors for RoP?
1) Prematurity (<32 weeks gestation).
2) Low birthweight (<1500g, significantly increased if <1250g).
3) Uncontrolled hyper-oxygenation (previously common practice to give high-flow oxygen to premature infants to ensure adequate oxygenation however this was shown to cause ischaemic effects in retinal development and is considered the first stage in the development of ROP).
How can high flow oxygen in premature infants cause RoP?
This was shown to cause ischaemic effects in retinal development and is considered the first stage in the development of ROP.
Over oxygenation (e.g. during ventilation) results in a proliferation of retinal blood vessels (neovascularisation).
What 3 zones is the retina divided into?
Zone 1 includes the optic nerve and the macula.
Zone 2 is from the edge of zone 1 to the ora serrata, the pigmented border between the retina and ciliary body.
Zone 3 is outside the ora serrata.
How is RoP staged?
The areas of disease are described from stage 1 (slightly abnormal vessel growth) to stage 5 (complete retinal detachment).
“Plus disease” describes additional findings, such as tortuous vessels and hazy vitreous humour.
Under what circumstances would babies be screened for RoP?
1) Infants born <31 weeks gestational age
OR
2) Infants born <1.5kg birth weight
