Perinatal Adaption Flashcards
What is the function of the placenta?
Fetal homeostasis Gas exchange Nutrient transport to fetus Waste products transport from fetus Acid base balance Hormone production Transport of IgG
What are the 3 fetal shunts?
Ductus venosus
Foramen ovale
Ductus arteriosus
How much of the fetal output goes via the lungs?
7%
What happens in the 3rd trimester to prepare the fetus for birth?
Surfactant production
Accumulation of glycogen - liver, muscle and heart
Accumulation of brown fat - between scapulae and around internal organs
Accumulation of subcut fat
Swallowing of amniotic fluid
What preparation occurs for labour and delivery?
At onset of labour - Increased cetacholamines and cortisol
Synthesis of lung fluid stops
vaginal delivery - squeezes lungs
What happens in the first few seconds following birth?
Baby is blue Starts to breathe Cries gradually goes pink Cord is cut
What transitions occur regarding the circulatory system?
Pulmonary vascular resistance drops Systemic vascular resistance rises Oxygen tension rises Circulating prostaglandins drop Duct constricts Foramen ovale closes
What happens to the foramen ovale?
Closes or persists as PFO (10%)
What happens to the ductus arteriosus?
Becomes ligamentum arteriosus
Persistent ductus arteriosus
What happens to the ductus venosus?
Becomes ligamentum teres
What failure of cardiorespiratory adaptation can occur?
Persistent pulminary hypertension of the newborn (PPNH)
How do you manage PPHN?
Ventilation Oxygen Nitric oxide Sedation Inotropes ECLS
What is altered in the first few hours after birth?
Thermoregulation
Glucose homeostasis
Nutrition
What helps change thermoregulation?
Large surface area
Wet when born
What 4 methods help heat loss?
No shivering
Non-shivering thermogenesis
Peripheral vasoconstriction
Help via external factors e.g. parents
What is Non-shivering thermogenesis?
Heat produced by breakdown of stored brown adipose tissue in response to catecholamines
Not efficient in first 12 hours of life
What problems in preterm babies can lead to hypothermia?
Low stores of brown fat
Little subcut fat
Larger surface area: volume
What is glucose homeostasis?
interruption of glucose supply from placenta
Very little oral intake of milk
Drop in insulin, rise in glycogen
Mobilisation of hepatic glycogen stores for gluconeogenesis
Ability to use ketones as brain fuel
What can cause hypoglycaemia?
Increase in energy demand (unwell, hypothermia)
Low glycogen stores (small, premature)
Inappropriate insulin:glucose ratio (Maternal diabetes, hyperinsulinism)
Some drugs
What reflex(es) help babies breastfeed?
Rooting and Suck
What does breastmilk contain?
Colostrum
What happens to fetal haemoglobin?
Becomes disadvantageous
Increase in 2,3 DPG shifts curve to the right
Where does Haematopoiesis move to?
Bone marrow
What is synthesised quicker, adult or fetal haemoglobin?
Fetal
What does the breakdown of fetal Hb cause and when is Nadir reached?
Physiological anaemia
8-10 weeks
What causes physiological jaundice?
Breakdown of fetal haemoglobin
Conjugating pathways immature
Rise in circulating unconjugated biliruben
Generally not harmful unless very high levels
When may jaundice be physiological?
In the first week
When may jaundice be pathological?
In the first 24 hours
After the first week
What are risk factors for adaptation issues?
Hypoxia/Asphyxia at delivery Particularly small or large babies premature babies Small maternal illnesses and medications Ill babies, sepsis, congenital anomalies
