2. Objectives
By the end of this session, the learner should be able
to:
1. Define a Normal Newborn
2. Describe the general characteristics of a
normal term newborn
3. Describe the physiological changes that take
place in the normal newborn
3. Definition
A normal newborn is an infant born
following a normal pregnancy, normal
labour and is delivered normally.
The infant is born at term. The 1 minute
Apgar score is 7 or more and no
resuscitation is needed after birth
5. General characteristics of
the Newborn
Appearance
Weight :
A normal term baby weighs 2.5 - 3.5 kg.
Boys are heavier than girls
Within the 1st three days, the baby looses
approx.10 - 20% of its birth weight.
They regain weight from the 6th day to 2 weeks.
6. General characteristics…..
Possible Reasons For Weight Loss In A Newborn
Due to tissue fluid loss which accompanies heat loss when
the baby is born
When the baby opens their bowels, the meconium which
was present in the gut is lost, leading to weight reduction
Poor sucking on the breast due to tiredness incurred during
the baby’s passage through the birth canal during labour
The use of adipose tissue as a source of energy by the
newborns
7. General characteristics…..
In 2 weeks they regain their birth weight
Within 3 months of birth, babies gain double their
birth weight
During their first month, most newborns gain weight at a
rate of about 30 grams per day.
Many newborns go through a period of rapid growth when
they are 7 to 10 days old and again at 3 and 6 weeks
8. General
characteristics…..
Head circumference:
34 - 35cm
The head is ¼ of the
size of the body
The anterior and
posterior fontanelle are
still patent
Posterior closes after 6
weeks, while anterior
closes at 18 months
9. Sutures - joints made of strong, fibrous tissue. They hold the
bones of the baby's skull together. The sutures meet at
the fontanels, the soft spots on the baby's head.
The sutures remain flexible during infancy, allowing the skull to
expand as the brain grows. The largest fontanel is at the front
(anterior).
11. .
The newborn’s
length/height ranges from
50-52cm from crown to
heels
They generally grow in
height about 1 to 1½ inches
(2.54 to 3.81 centimeters)
during the first month.
12. .
Baby has a prominent
abdomen
The baby lies in an
attitude of complete
flexion
13. General characteristics…..
Skin
Is thin, delicate and easily traumatized by friction,
pressure and substances with a different PH
Prone to blistering, excoriation and infection
The PH of a term baby's skin is 6.4, and reduces to 4.9
over 3 – 4 days to protect against infection
Covered by vernix caseosa (a sticky substance produced by
sebaceous gland), which protects the baby and helps retain
heat in utero. Also acts as a lubricant during delivery
Sebaceous glands cease to produce vernix after birth,
which may lead to dryness of the skin.
Vernix caseosa will peel off within 3 days of birth if left
alone.
14. General characteristics…..
Skin …..
May have fine hair called lanugo, found over the
shoulders, upper arms and thighs. It disappears
within the 1st month of life (MORE IN PRETERM BABIES)
Have plentiful skin creases of the hands and sole of
feet
Peripheral cyanosis is common
Sweat glands although present are not active in the
1st days of life
16. Characteristics….
Nails are fully formed and
may even be too long
Hair is soft and silky,
some babies have no hair
Eye brows and eye lashes
are present
Cartilage of the ear is well
formed
17. Characteristics….
Umbilical cord:-
Shrinks slowly by a process
of dry gangrene.
Usually falls off by 5 -14 days
Prolonged separation
caused by:
Infection
Use of antiseptics which
reduce the number of non
pathogenic flora
18. Characteristics….
Genitalia
Boys
Have testicles descended into the scrotum
Prepuce is adherent to the glans penis
The urethral meatus opens at the tip of the penis
Girls:
Labia majora covers the labia minora except for preterms
The hymen and clitoris may appear
disproportionately large
Both boys & girls have a nodule of breast tissue around
the nipple
19. Physiology of the
Newborn
Immediately after birth, there are 3 main
physiologic adjustments that take place
involving the lungs, the CVS & the temperature
regulating centre to allow for the independent
existence of the newborn baby;
1. Initiation of respiration - Changes in the resp.system
2. Changes in the cardiovascular system
3. Temperature regulation/thermal adaptation
20. 1. Initiation of respiration
Onset of respiration confirms life.
The start of pulmonary respiration is due to
physiological and mechanical reasons
i) Physiologically
Lack of O2 and high levels of CO2 in the circulation
occur when placental circulation ceases.
This stimulates the respiratory center in the medulla to
initiate normal respiration
21. Initiation of respiration….
ii) Mechanically
Respiration is stimulated when the chest wall, which was
compressed during the passage of the baby in the birth
canal, allows the fluid to drain from the lungs.
Cool air on the baby’s face and handling during birth will
stimulate the baby to cry as soon as they are born.
After the baby takes in their first breath, the blood
vessels in the lungs expand to initiate respiration.
Vigorous cry should be encouraged in order for lungs
to be aerated completely
22. Initiation of respiration….
Breathing is mainly diaphragmatic, chest and
abdomen raising and falling synchronously.
The breathing is shallow and irregular at 1st
with periods of apnea. Normal Respiratory
Rate: 40- 60 breaths/min
The pattern of respiration alters during sleep
and waking state
NOTE: Babies are nose breathers, and can not convert
automatically to mouth breathing when nasal obstruction occurs
23. 2. Changes in the CVS
With the establishment of respiration, blood is
drawn to the lungs through pulmonary arteries,
then returns to the left atrium via pulmonary
veins.
As the placental circulation ceases soon after
birth when the umbilical cord is ligated, blood flow
to the right side of the heart decreases and flow
to the left side increases causing:-
24. Changes in the CVS….
i. Foramen ovale to close
ii. Ductus arteriosus closes within 8-10 mins of birth, but
ceases to function with establishment of pulmonary
respiration which increases oxygen conc in blood,
constricting ductus arteriosus
iii. Ductus venosus and hypogastric arteries cease to
function within a minute of birth.
iv. The umbilical vein, ductus venosus and hypogastric
arteries collapse.
NB: Anatomical closure by fibrous tissue occurs
within 2-3 months after birth
25. Changes in the CVS….
The blood
The total circulating blood volume at birth is 80ml/kg
body weight. This may be raised if clamping of the
umbilical cord is delayed at birth
The Hemoglobin level is high 13-20g/dl (50-85% of this is
fetal Hb)
NB: Conversion of fetal to adult Hb, which commenced in utero, is
completed in the first 1-2 years of life.
The Heart Rate is 110-160b/min,& fluctuates with the baby's
respiratory function & activity or sleep state
Peripheral circulation is sluggish resulting to mild
cyanosis of extremities (feet, hands)
BP fluctuates according to activity from 50-55/23-
30mmHg to 80/50mmHg in the 1st 10 days of life.
26. Changes in the CVS….
Hb, RBC count & haematocrit levels decrease gradually
during the first 2-3 months of life, at this time erythropoiesis
is suppressed
The WBC count is high initially but decreases rapidly
Breakdown of excess RBCs in the liver and spleen
predisposes to jaundice in the 1st week of life
Low Vit. K - dependant clotting factors II (prothrombin), VII,
IX, and X, inhibit blood clotting during the 1st wk.
because colonization of intestines by normal flora that
synthesize Vit.K is delayed till feeding is established
27. 3. Temperature Regulation
/thermal adaptation
The neonate leaves a thermo constant environment of
37.1 degrees Celsius in utero, to a cooler environment
at delivery. This affects the neonate in various ways;
Heat regulation in the neonate is poor because of inefficient heat regulating
centre (hypothalamus)
The subcutaneous layer of the neonate is thin and provides poor insulation,
allowing transfer of heat to the environment and cooling the baby's blood -
heat loss by evaporation
Heat will be lost by conduction when baby is in contact with cold surfaces
By radiation to cold objects in the environment and
By convection when heat is lost by cool air passing over the surface of the
baby's body
29. Keeping a newborn baby warm
after delivery
Method of heat loss Prevention
Evaporation: Wet baby Immediately after birth dry
baby with a clean, warm,
dry cloth
Conduction: Cold surface
e.g weighing scale etc.
Put the baby on the
mother’s abdomen or on
a warm surface
Convection: Cold draught Provide a warm, draught
free room for delivery at
≥25oC
Radiation: Cold metallic
surroundings
Keep the room warm
30. Thermal adaptation……
The baby's normal core temperature is 36.5 - 37.3
degrees centigrade
A healthy clothed term baby will maintain this body
temp satisfactorily, provided environmental temp is
sustained btwn18 - 21 degrees Centigrade
Using conditioning systems in delivery rooms can have
a risk of overheating or chilling the baby
The baby can also get hypothermia when exposed to
cold or draughts, when wet, when unable to move
about freely, or deprived of nutrition
Babies are not able to shiver, so they are not able to
voluntarily produce heat
31. Thermal adaptation…..
Cold stress can cause resp. and metabolic acidosis
Unstable temperature may indicate infection
Hyperthermia may be seen by sweating on the
forehead
Signs of cold stress (Hypothermia)
Adopt a fetal flexed posture – to try & maintain body temp.
Increased resp. rate and activity.
Baby may cry
Note: The above signs increases calorie consumption which may
lead to hypoglycemia.
32. *How to prevent cold stress
Maintain temp of delivery room btw 21-24 degree
centigrade
Dry the baby immediately to prevent heat loss by
evaporation
Wrap baby in warm clothes and encourage the mother to
hold baby skin to skin contact
Windows of labour room should be in a way that they do
not encourage heat loss by radiation
Cover the head of the baby
The clothing should be loose and the baby can move
freely
Feed the baby early
