Normal adaption to extrauterine environment

Question 1

Routine neonatal assessment.

Answer 1

• General appearance - obvious abnormality?
• Growth: HC, length, weight
• Head: face, neck: fontanelles, cleft palate
• Eyes: red light reflex (congenital cataracts)
• Limbs: movement, deformity, digits
• Lungs: Colour, respiratory effort (rate, recession, grunting, nasal flare), mediastinal shift, auscultation
• Heart: Assessment of colour, pulses (femoral), heart sounds, and murmurs
• Abdomen- Shape, umbilicus, organomegaly
• Genitalia - hypospadius or other possible ambiguity (such as bilateral undescended testes), anus (site, patency)
• Hips: DDH
• Back + spine: Scoliosis, tumours, dermatological markers of spinal dysraphism
• Neuro: tone, movements, reflexes (moro, grasp, suck)

Question 2

The APGAR score.

Answer 2

Routinely done at 1 and 5 minutes after birth.
If required - Repeated every 5 minutes until APGAR normalises, until max 20 minutes.
5 components, each scored 0-2.
Score>/=7 is considered normal.

Activity/tone: Active +2, Some flexion +1, Nil 0

Pulse: HR>100 +2, HR <100 +1, None 0

Grimace: Sneeze/cough +2, Grimace +1, none 0

Appearance/colour: All pink +2, blue extremeties and pink body +1, blue/pale 0

Respirations: Good crying +2, irregular/slow +1, absent 0

Question 3

What are the shunts in fetal circulation and what is their purpose?
What happens after birth?

Answer 3

In the fetus oxygenated blood is obtained via the placenta and carried in the umbilical vein.
3 shunts which are designed to bypass the liver and lungs, and ensure delivery of oxygenated blood to priority fetal organs (i.e. heart, brain and adrenals).

1. ductus venosus - connects umbilical vein to IVC above level of liver, thus bypassing the liver.
2. Foramen ovale - shunts oxygenated blood from the right atrium to left atrium, thus bypassing the lungs.
3. Ductus arteriosus - shunts blood from pulmonary arteries into aorta, thus bypassing the lungs.

Shortly after birth these 3 shunt systems should close. The newborn changes from relying on the fetoplacental unit, to relying on pulmonary ventilation for oxygenation.
With inflation of the lungs pulmonary vasculature resistance drops and pulmonary blood flow increases, causing right atrial pressure to be less than the left atrium, which causes the ductus arteriosus and the foramen ovale to close.

Question 4

Why are newborns susceptible to hypothermia?

Answer 4

• wet
• naked
• born into cold environment relative to in utero
• Increased surface area after born due to uncurling from fetal position
• Unable to shiver
• Glycogen stores in liver are deposited during 3rd trimester and are highest at term; these are necessary energy source till gluconeogenesis starts around day 2-4 after birth; preterm babies have to rely on brown fat stores for metabolism and heat.

Question 5

Is the APGAR score useful for predicting long term outcome? Can it be used in preterm infants?

Answer 5

Poor correlation with long term outcomes, including cognitive disability.
Only APGAR <5 - at 5 and 10 mins is correlated with increased risk of cerebral palsy.

It can be used in preterm infants, though recognising tone and movement will always be less in extremely preterm infants.

Question 6

What is developmental dysplasia of the hip?
Prevalence?
Management?

Answer 6

A congenital abnormality where the hip socket is too shallow predisposing to dislocation of one or both hips.
Tested at the routine new born examination and recheck at 6-8 week baby check.

Prevalence 1-2/1000

Managed with ‘pavlik harness’ (material splint) if detected early.
If the pavlik harness doesn’t work, or only detected late (>6 months) may require surgery for one/closed reduction of the hip and casting.

Question 7

When and how is newborn screening done?

What is tested for?

Answer 7

Blood spot testing by taking a heel prick sample of blood.
Done day 3-5 after birth.

Testing for:

• Congenital hypothyroidism
• Cystic Fibrosis
• Severe combined immunodeficiency (SCID)
• Congenital adrenal hyperplasia (CAH)
• Inherited metabolic diseases: phenylketonuria, medium-chain acyl-CoA dehydrogenase deficiency (MCADD), maple syrup urine disease (MSUD), isovaleric acidaemia (IVA), glutaric aciduria type 1 (GA1) and homocystinuria (pyridoxine unresponsive) (HCU)

NB. varies country to country - e.g. UK screens for sickle cell, but not CAH and SCID…

Question 8

What are the pros and cons of male circumcision?

Is it endorsed by RANZCOG?

Answer 8

No its not endorsed, but if requested by parents careful counselling and arrangements can be made.
10-20% male infants in Australia are circumcised.

Pros:
- Reduce risk recurrent UTI, STI in adults, reduce HIV in high prevalence populations, reduce risk certain penile cancers if phimosis, for religious/cultural beliefs and inclusion

Cons:
- foreskin has a functional role, non-therapeutic /non-indicated procedure, infant has no chance to consent