Adaptation at Birth Flashcards
List some of the various functions of the placenta.
- Foetal homeostasis
- Gas exchange
- Nutrient transport to foetus
- Waste product transport from foetus
- Acid base balance
- Hormone production
- Transport of IgG
What controls most of the homeostasis for the baby?
Placenta
The placenta is essentially another organ that develops inside the ______ during pregnancy to provide ______ and _________ to the baby and remove _____
- Uterus
- Nutrients
- Oxygen
- Waste
Where does the placenta attach to?
The walls of the uterus
What attaches the baby to the uterus?
Umbilical cord
What is it called when the placenta is misplaced as lies over the opening of the cervix?
Placenta praevia
In the late stages of pregnancy, amniotic fluid is swallowed by the baby and the amniotic fluid will eventually become most of the babies urine
True
There are 3 shunts in foetal circulation. Name these.
- Ductus venosus
- Foramen ovale
- Ductus arteriosus
Describe ductus venosus.
A vein passing through the liver and connecting the left umbilical vein with the IVC of the foetus, losing its circulatory function after birth, and persisting as the ligamentum venosum of the liver
Describe foramen ovale.
An opening in the septum between the two atria of the heart that is normally present only in the foetus
Describe ductus arteriosus.
Also called the ductus Botalli, is a blood vessel connecting the main pulmonary artery to the proximal descending aorta. It allows most of the blood from the right ventricle to bypass the foetus’s fluid-filled non-functioning lungs
Surfactant production + alveoli formation occurs at how many weeks?
36 weeks
When does preparation for birth occur (trimester)?
3rd trimester
What is there an accumulation of during the 3rd trimester (in preparation for birth)? Why?
Glycogen – liver, muscle, heart
When the baby is born it breaks down glycogen as a form of glucose as it is no longer receiving this from the mother
What is there an accumulation of during the 3rd trimester (in preparation for birth)?
Glycogen – liver, muscle, heart
Brown fat
SC fat
What is the accumulation of SC fat in preparation for birth important for?
This is important for maintaining foetal temperature after birth
Why is the swallowing of amniotic fluid in the 3rd trimester important for preparation for birth?
The amniotic fluid helps to mature the foetal GI tract
What is the accumulation of glycogen in preparation for birth important for?
When the baby is born it breaks down glycogen as a form of glucose as it is no longer receiving this from the mother
What hormones increase when the mother goes into labour?
Increase in catecholamines (e.g cortisol and adrenaline)
What colour is a baby in the first few seconds of life?
BLUE - but this is normal
What happens to the baby in the first few seconds following birth?
- BLUE
- Starts to breathe
- Cries
- Gradually goes pink
- Cord is cut
Why is it so important for the baby to cry?
Huge negative intrathoracic pressure – breath out crying against a closed glottis – pushes back against fluid in lungs to go into lung interstitial fluid to return back to the circulation
Try not to cut the cord at first (unless the baby needs RESUS). How long should you leave it for?
At least 1 minute
What duct closes initially during circulatory transition?
Foramen oval
Describe the features of the circulatory transition.
- Pulmonary vascular resistance drops
- Systemic vascular resistance rises
- Oxygen tension rises
- Circulating prostaglandins drop
- Duct constricts
In the lungs, O2 is a potent ___________
Vasodilator
In the duct, O2 is a potent ______________
Vasoconstrictor
What closes the foramen ovale?
Pressure rise in the left side of the heart
What, made in placenta, are important in relaxing the duct smooth muscle?
Prostaglandins
When the baby is born, there is vasoconstriction due to?
- Increased pO2
- Decreased flow
- Decreased prostaglandins
What duct closes after brith?
Foramen vale
What happens if the foramen ovale does not close following birth?
Patent Foramen Ovale (10%)
What does the ductus arteriosus become after birth?
Ligamentum arteriosus
What does the ductus venosus become after birth?
Ligamentus teres
What does the ductus venosus become after birth?
Ligamentus teres - also known as the round ligament of the liver
Describe the ligamentum teres.
A degenerative string of tissue that exists in the free edge of the falciform ligament of the liver
What is persistent pulmonary hypertension of the newborn?
The failure of the normal circulatory transition that occurs after birth
What is persistent pulmonary hypertension of the newborn?
The failure of the normal circulatory transition that occurs after birth
It is a syndrome characterized by marked pulmonary hypertension that causes hypoxemia secondary to right-to-left shunting of blood at the foramen ovale and ductus arteriosus
Blue blood goes across into left atrium and ventricle + high resistance to flow …. what condition does this happen in?
Patent Foramen Ovale
There will be a difference in saturation of right hand and foot if?
Patent Foramen Ovale
What is NO?
A potent vasodilator
Outline the management of PPH of the Newborn.
- Ventilation
- O2
- Nitric oxide
- Sedation
- Inotropes
- ECLS
Where is NO produced in the body?
Vascular endothelium of all tissues
Babies are wet when born. Heat loss occurs by 4 methods …
No shivering – main source of heat production is by non-shivering thermogenesis
Heat produced by breakdown of stored brown adipose tissue in response to catecholamines
+
Peripheral vasoconstriction
The methods of heat conservation of a baby do not work within the first __ hours of life
12
Why are pre-term babies more likely to get hypothermia when they are born?
- Low stores of brown fat
- Little subcutaneous fat
- Larger surface area : volume ratio
How can you prevent hypothermia of the newborn?
Skin-to-skin/ blanket + hat
- Dry
- Hat
- Skin to skin
- Blanket / clothes
- Heated Mattress
- Incubator
How much milk does a baby need when it is born?
0.5-1ml of colostrum from breastmilk when they are born
How big is a babies stomach when it is born?
The size of a walnut, thus it needs very little milk
What does a baby mobilise when born for energy?
Mobilisation of hepatic glycogen stores for gluconeogenesis
What can a baby use as brain fuel?
Ketones
Drop in insulin, increase in glycogen occurs in the baby after birth. When did the baby acquire these glycogen stores?
They break down glycogen stores (via glucagon) made in pregnancy for sugar
Give 4 examples of situations which can cause hypoglycaemia of the newborn.
- Increased energy demands (unwell, hypothermia)
- Low glycogen stores (small, premature)
- Inappropriate insulin:glucagon ratio (maternal diabetes, hyperinsulinism)
- Some drugs – especially Labetalol
Babies with diabetic mums don’t have enough insulin around
FALSE - they have too much insulin around
What drug causes neonatal hypoglycaemia?
Labetalol
Insulin switches off ______ production
Ketone
Babies start to suckle instantly from birth because of what reflex?
‘rooting and suck’ reflex
What is breastmilk rich in?
Colostrum
Babies gain weight in the first few days of life
FALSE - they lose around 10%
In utero, what does foetal haemoglobin have a high affinity for?
O2
What does foetal Hb do to the 2,3 DPG curve?
Shifts the curve to the right
Why do babies have some degree of anaemia after birth?
Adult Hb synthesised more slowly than fotal Hb is broken down and thus at around 8-10 weeks
Why do babies become physiologically jaundice?
The liver enzyme pathways are present but immature
Outline the physiology of jaundice.
- Breakdown of foetal haemoglobin occurs, but conjugating pathways are immature
- This results in a rise in circulating unconjugated bilirubin
Outline the treatment of jaundice of the newborn.
- Phototherapy (1st line)
* Exchange transfusion (2nd line)
