Adaptation at Birth Flashcards
what are the functions of the placenta?
foetal homeostasis
gas exchange
nutrient transport to and waste product transport from foetus
acid base balance
hormone production
transport of IgG
what are the 3 shunts of foetal circulation?
ductus venosus
foramen ovale
ductus arteriosus
what is the fate of the 3 shunts of foetal circulation - ductus venosus, foramen ovale and ductus arteriosus?
ductus venosus = becomes ligamentum teres
foramen ovale = closes (may persist as PFO in 10% - “hole in the heart”
ductus arteriosus = becomes ligamentous arteriosus
what changes occur during the 3rd trimester to prepare for birth at term?
surfactant production = lung function
accumulation of glycogen = liver, heart, muscle
accumulation of brown fat = between scapulae and around internal organs
accumulation of subcutaneous fat
swallowing amniotic fluid
what changes occur during labour and delivery to prepare for birth?
inceased catecholamines / cortisol = onset of labour
synthesis of lung fluid stops
vaginal delivery = squeezes lungs
what changes occur during the first seconds after birth of term delivery?
blue -> breathes -> cries -> pink
cord cut
circulatory transition
what specifically occurs during the circulatory transition which occurs in first few seconds of life?
pulmonary vascular resistance drops as systemic vascular resistance rises
oxygen tension rises
circulation prostaglandins drop
duct constricts - increase pO2, decreased flow and prostaglandins
foramen ovale closes
what is an example of the failure of cardiorespiratory adaptation in newborn and how is this treated?
persistent pulmonary hypertension of newborn (PPHN)
tx = ventilation, oxygen, nitric oxide, sedation, inotropes, ECLS
what changes occur in thermoregulation during the first few hours after birth?
main source of heat production is via non-shivering thermogenesis - heat produced by breakdown of stored brown adipose tissue in response to catecholamines, not efficient in the first 12 hours of life
peripheral vasocontriction
newborn babies need help maintaining temperature
what changes occur in glucose homeostasis during first few hours of birth?
there is an interruption of the glucose supply from placenta and very little intake of milk resulting in an insulin drop and increase in glycogen
there is a mobilisation of hepatic glycogen stores for gluconeogenesis and an ability to use ketones as brain fuel
what changes occur in nutrition during the first few hours of life?
breast feeding
baby starts to suckle and the feedback loop causes an increase in supply and a change in breast milk composition (colostrum, foremilk and hindmilk)
what haematological changes occur after birth?
foetal haemoglobin becomes disadvantageous: an increase in 2,3 BPG moves curve to the right
haematopoiesis moves to the bone marrow but adult Hb is synthesised more slowly than foetal Hb is broken down (causes physiological anaemia, lowest point ie nadir is at 8-10 weeks)
what is the cause of physiological jaundice?
liver enzyme pathways (conjugating pathways) are present but immature
this combined with the breakdown of foetal haemoglobin causes a rise in circulating conjugated bilirubin
*generally, not harmful
all babies need help to maintain temperature but why are small for dates babies more prone to hypothermia?
low stores of brown fat
little subcutaneous fat
larger surface area:volume
how is hypotheramia treated in babies?
dry
hat
skin to skin
blanket / clothes
heated mattress
incubator
