Perinatal Adaptation

Question 1

what is the function of the placenta

Answer 1

fetal homeostasis 
gas exchange 
nutrient transport to fetus 
waste product transport from fetus 
acid base balance 
hormone production 
transport of IgG

Question 2

what are the three shunts involved in the fetal circulation

Answer 2

Ductus venous
Foramen ovale
Ductus arteriosus

(only 7% of fetal blood goes to the lungs bc obvs doesn’t need to if they’re not working yet)

Question 3

where is the foramen oval

Answer 3

between the right and left atria

Question 4

where is the ductus arteriosus

Answer 4

connects the pulmonary artery trunk and the arch of the aorta

(can be closed by prostaglandins)

Question 5

where is the ductus venous

Answer 5

connecting the umbilical vein and the inferior vena cava so that oxygenated blood from the placenta can get pumped around the body

Question 6

what preparation for birth occurs in the fetus in the third trimester

Answer 6

surfactant production

accumulation of glycogen in liver, muscle and heart

accumulation of brown fat (between scapulae and around internal organs)

accumulation of subcutaneous fat

swallowing amniotic fluid

Question 7

what preparation for birth occurs in the fetus during labour and delivery

Answer 7

onset of labour increases catecholamines and cortisol

synthesis of lung fluid stops

during Vaginal Delivery - lungs are squeezed together (helps with getting rid of fluid)

Question 8

what happens to the baby in the first seconds after birth

Answer 8

blue 
starts to breath 
cries
gradually goes pink 
cord is cut

Question 9

what causes the transition of the fetal circulation to the baby’s circulation

Answer 9

pulmonary vascular resistance drops

systemic vascular resistance increases (making blood go to the lungs instead)

oxygen tension rises

circulating prostaglandins drop

ductus arteriosus constricts

foramen vale closes

Question 10

what causes the constriction of the ductus arteriosus

Answer 10

increases pO2

decreased blood flow
decreased prostaglandins

Question 11

what happens to the foramen ovale after birth

Answer 11

closes or persists as PFO in 10%

Question 12

what happens to ductus arteriosus after birth

Answer 12

Becomes ligament arteriosus

OR

PDA (persistent ductus arteriosus)

Question 13

What happens to the ductus venous after brith

Answer 13

becomes ligamentum teres

Question 14

what is persistent pulmonary hypertension of the newborn

Answer 14

failure of cardiorespiratory adaptation in the new born

Question 15

how do you manage PPHN

Answer 15

ventilation 
oxygen 
nitric oxide 
sedation 
inotropes 
Extra corpeal membrane oxygenation

Question 16

what is transient tachypnoea of the newborn

Answer 16

impaired lung function as fetal lung fluid has not been cleared properly

usually goes away without treatment in a few days

Question 17

why do newborn babies loose heat so easily

Answer 17

they have a large surface area to volume ratio

wet when born

they can’t shiver

Question 18

what are the 4 methods of heat loss in babies

Answer 18

conduction (through contact surfaces)
Convection (movement of air)
Evaporation (born wet)
Radiation

Question 19

how do babies regulate their temperature

Answer 19

heat is produced by breakdown of stored brown adipose tissue in response to catecholamines

(this is not efficient in the first 12 hours of life )

peripheral vasoconstriction

Question 20

why are small for dates/ preterm babies at higher risk of hypothermia

Answer 20

low stores of brown fat

little subcutaneous fat

larger surface area to volume ratio

Question 21

how do you prevent hypothermia in a new born

Answer 21

get them dry 
put on a hat 
skin to skin contact 
blanket/clothes 
heated mattress 
incubator

Question 22

how is glucose homeostasis maintained in the newborn

Answer 22

no longer get glucose supply from placenta and aren’t taking in much milk so:

drop in insulin
mobilisation of hepatic glycogen stores for gluconeogenesis
ability to use ketones as brain fuel

Question 23

what causes hypoglycaemia

Answer 23

increased energy demands (eg. unwell or hypothermia)

low glycogen stores (eg. if premature)

maternal diabetes

hyperinsulinism (some drugs)

Question 24

how do you avoid/treat hypoglycaemia in babies

Answer 24

identify those at risk
feed effectively
keep warm
monitor

Question 25

how does the mother know to keep producing breast milk

Answer 25

baby starts to suckle (rooting and suck reflex)

feedback loop causes increase in supply (oxytocin and prolactin released)

composition of the milk changes as the baby gets bigger

• colostrum
• foremilk and hindmilk

Question 26

what hormone is responsible for milk production

Answer 26

prolactin

Question 27

what hormone is responsible for milk ejection

Answer 27

oxytocin

Question 28

what happens to haemoglobin when the fetus becomes a baby

Answer 28

an increase in 2,3 BPG shifts the oxygen saturation curve to the right

this causes haematopoeisis to move to town marrow and Hb is synthesised more slowly and broken down

physiological anaemia occurs

Hb is at its lowest point at 8-10 weeks

Question 29

why do babies get jaundice

Answer 29

Liver enzyme pathways are immature

physiological jaundice

early or prolonged jaundice my be pathological

Question 30

what is physiological jaundice

Answer 30

breakdown of fetal haemoglobin

conjugating pathways are immature

rise in circulating unconjugaed bilirubin

this is generally not harmful unless very high levels

Question 31

how do you treat a baby with physiological jaundice

Answer 31

blue light phototherapy

if v bad - exchange transfusion

Question 32

what babies are at higher risk of adaptation problems

Answer 32

hypoxia/asphyxia during delivery

particularly small or large babies

some maternal illnesses and medications

if baby is ill - sepsis, congenital anomalies