1.2 Adaptations of Extra uterine life Flashcards
The APGAR score is used to assess a newborn baby, which allows us to see if the baby is adapting as they should to the outside world:
• Baby is scored at ____________ after delivery (minimum 0; maximum 10)
• Babies are normally born blue and cry immediately → normally establish regular breathing after stimulation by _________________ with heart rate of ____________ at birth
• Normally very vigorous at birth and pink up at about ____________
1, 5, and 10 minutes ;
30 seconds of life;
> 100 bpm;
3 minutes of life
what is the criteria for 0/1/2 points for alertness (APGAR score)?
- 0 points: limp
- 1 point: weak, some movement
- 2 points: actively moving arm and legs
what is the criteria for 0/1/2 points for pulse (APGAR score)?
- 0 points: none
- 1 point: <100 bpm
- 2 points: >100 bpm
what is the criteria for 0/1/2 points for grimace (APGAR score)?
- 0 points: no reflexes
- 1 point: grimace
- 2 points: cry or active avoidance
what is the criteria for 0/1/2 points for appearance (APGAR score)?
- 0 points: pale or blue all over
- 1 point: pale or blue in hands and feet
- 2 points: pink
what is the criteria for 0/1/2 points for respiration (APGAR score)?
- 0 points: absent
- 1 point: irregular, shallow, or gasping breaths, weak cry
- 2 points: full breaths, strong cry
The passage through the birth canal is a hypoxic event for the foetus:
• Normal vaginal delivery: lung fluid is reabsorbed by the ____________ and _______________ extrudes fluid from the trachea
• Sudden changes in ____________ stimulates the baby to take its first gasp of air (reflex gasping) ~6s after delivery → regular breathing at _______
o Crying fully opens the lungs and fluid is absorbed → allows air to enter and establish a resting lung volume
Transient tachypnoea of the newborn (TTN): may be caused by a ___________________ as the tracheal fluid takes longer to be reabsorbed after LSCS
- Chest is not squeezed unlike in a normal vaginal delivery –> tracheal fluid not extruded
- baby breathes faster to obtain sufficient oxygen and to extrude fluid
lymphatic and pulmonary systems;
squeezing of the chest;
environment and temperature;
~30s;
lower uterine segment Caesarean section (LSCS)
The umbilical cord must be clamped/cut to allow the baby to adapt to extrauterine life:
• Allows transition from placental to neonatal circulation (various structural changes)
• Recommendation: delay cord clamping by ______________ from complete delivery of the infant for uncompromised babies → reduces risk of ______________ later in life
1 minute;
iron deficiency
what does ductus arteriosus (DA) become?
Ligamentum arteriosum
what does ductus venosus (DV) become?
Ligamentum venosum
what does foramen ovale (FO) become?
Fossa ovalis
what does umbilical vein become?
Ligamentum teres (of liver)
what does umbilical arteries become?
Medial umbilical ligaments
In what scenarios will the ductus arteriosus be kept open?
- Prematurity (high foetal prostaglandin levels keeps duct open)
- Cyanotic heart disease (e.g. transposition of great vessels, pulmonary atresia) → need to actively keep duct open to allow flow to lungs
- Maternal rubella infection (associated with PDA in 80%)
- Genetic abnormalities (e.g. Down syndrome, Noonan’s syndrome)
what are mechanisms for heat loss in the body?
- Radiation (temperature difference between skin and surrounding surfaces)
- Evaporation (transepidermal loss → especially for preterm babies)
- Conduction (placed on cold surface)
- Convection (exposure to cool draft of air)
what are the strategies to reduce heat loss in the baby?
- Dry the baby
- Wrap the baby up in a towel
- Use a warm towel
- Nurse in closed environment (e.g. cot, incubator) away from draft
If the baby is still cold or various management strategies are not undertaken, the newborn continues to lose heat → skin receptors send signals to the brain:
• Conservation of heat: _______________ position (insulate themselves) and skin __________ (avoid heat loss)
• Generation of heat: shivering and burning _____________ (only found in foetuses and newborns) → burns essential glucose stores and causes future problems
curled up;
vasoconstriction;
brown fat stores
Thermal stress in newborn: hypothermia (< 35°C) increases morbid ity and mortality
- Associated with increased oxygen consumption (with ___________, __________, ___________), apnoea, failure to gain weight, neonatal cold injury (sclerema), reduced blood coagulability
- Sclerema neonatorum (SN) is a rare disease characterized by firm, indurated, waxy skin lesions extending throughout the body, sparing the fat-free soles, palms, and genitalia
hypoxia, hypoglycaemia, metabolic acidosis
RENAL ADAPTATIONS
Nephrogenesis is completed by 35 weeks of gestation and begin to function after birth:
• Newborn GFR (1.5 mL/kg/min) is low compared to adult GFR (2 mL/kg/min) → rises quickly in the first 2 weeks of life
• Start to urinate by ____________ + kidneys regulate fluid and electrolyte balance
• Marked reduction in body water (extracellular fluid) in the first 2 weeks → initial fall in ___________
• Insensible water loss via _______________ is high (especially in preterm infants → must nurse in _____________)
24 hours of life;
body weight;
transepidermal loss;
humidified conditions
HEPATIC ADAPTATIONS
The foetal liver acts as a store for _______________ → takes on more functions after birth:
• Production of _____________ (in case of injury in extrauterine environment)
• Breakdown of waste products (e.g. excess red blood cells) → ___________
• Production of _______________(conjugates bilirubin for excretion in bile or urine → prevents neonatal jaundice)
o Enzyme activity is actively downregulated in utero as bilirubin must be unconjugated to _____________ (prevents accumulation in foetus)
o Takes some time after birth to gain function
glycogen and iron;
clotting factors;
haemolysis ;
glucuronosyltransferase ;
cross the placenta
The gastrointestinal system remains not fully functional until after birth:
• Foetus produces a _____________ in late pregnancy → passes meconium by 48 hours of life
• Foetuses sometimes pass stools while in utero
- if a baby doesn’t pass meconium over the first 48 hours, questions are raised over the functionability of the baby’s GI system. Ddx such as __________
tarry green/black stool (meconium);
hirchsprung disease
The foetus is entirely dependent on transplacental nutrient transfer from the mother → blood glucose falls rapidly after birth:
• Glucose levels reach their lowest at ______________ and rises again by 3 hours (due to fall in insulin → allows __________ surge in response to corticosteroid-mediated stress response → mobilisation of ______________)
o _________________ increases to a high level within 12 hours
• Important to establish a first feed within ___________ (especially for babies at risk of developing hypoglycaemia e.g. mother with GDM)
o These babies were exposed to high sugar throughout pregnancy → high ____________ levels persist at birth → further drive hypoglycaemia neonatally
o Monitor ___________________ actively
1 hour of life;
glucagon;
liver glycogen;
Ketone body production;
1 hour of birth ;
foetal insulin;
neonatal blood glucose levels
what are complications of GDM?
- Miscarriage/stillbirth
- Large for gestational age: Causes difficult delivery → increased rate of C-sections, brachial plexus injuries, trauma (shoulder dislocation), perinatal asphyxia
- Prolonged jaundice: Due to increased growth hormone → polycythaemia → increased haemolysis → neonatal liver not mature enough to conjugate and excrete excess bilirubin produced → jaundice
- Prematurity and TTN: Develop signs of respiratory distress syndrome
- Hypertrophic cardiomyopathy: Usually interventricular septal hypertrophy (most affected infants are clinically asymptomatic → resolution within months)
Haematopoiesis changes throughout foetal life (begins in the ________ → _________ by end of 1st trimester → _____________ beginning at 5th month and predominates by birth):
• Predominantly ______ in the foetus (higher oxygen affinity) → beneficial in the relatively hypoxic environment of the foetus → shifts curve left
• Change from HbF to HbA (late foetal life to 6 months of age) + high Hb concentration at birth (15 – 23 g/dL) → reflects ___________ at birth
• Hb levels rise in the 1st day of life due to extracellular fluid loss → exacerbated by _____________
yolk sac ;
liver;
bone marrow;
HbF;
asphyxia ;
delayed cord clamping
Maternal IgG crosses the placenta in the ________________ (passive immunity) → neonatal response is _________:
• Newborn acquires adaptive features due to microbial exposure
extreme premature babies missed out on the transfer, important that baby is __________ to not miss out.
Pro inflammatory- if have infections, lots of release of cytokines, toxic proteases, thought to produce end organ failure if severe.
3rd trimester
proinflammatory;
breast fed
