Growth and Development

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Growth and Development

• Prepared by Dr. Lami Salah
• Moderator Dr. Jareer Halazoun

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• Some Definitions
• Fetal life period from 9th week of gestation
  till birth.
• Perinatal period period from 20th week of
  gestation till 28 day after birth.
• Prenatal period period from 20th week of
  gestation till birth.
• Postnatal period period from birth till 28th day
  after birth.
• Neoborn 1st week of life

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• Neonate 1st 28 days of life.
• Infancy first one year of life.
• Toddler 2-4 years of life.
• Preschool 4-5 years of life.
• School 6-12 years of life.
• Adolescence above 12 years.

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• The most dramatic events in growth and
  development occur before birth.
• As the process of growth and development is so
  much complicated much can go wrong.
• Specially that the uterus is permeable to adverse
  social and environmental influences such as
• -maternal under nutrition.
• -alcohol
• -cigarette
• -Drugs
• -and even psychological trauma.

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Somatic Development

• Embryonic Period (from fertilization to the end
  of 8th week of gestation)
• -by 6 days postconceptual age, as implantation
  begins, the embryo consists mainly of a spherical
  mass of cells with a central cavity called
  Balstocyst.
• -by 2 weeks
• -implantation is complete and the
  uteroplacental circulation has begun
• -the embryo has 2 distinct layers, ectoderm
  and endoderm.

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• -by 3 weeks
• -the third primary germ layer (mesoderm) has
  appeared along with primitive neural tube and
  blood vessels.
• -4-8 weeks
• -lateral folding of the neural plate followed
  by growth at the cranial and caudal ends.
• -budding of arms and legs produces a human like
  shape
• -precursors of skeletal muscles,, vertebrae,
  along with the branchial arches that will form
  the mandible, maxilla, palate, external ear and
  other head and neck structures start to develop.

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• -by the end of the 8th week the rudiments of all
  major organ systems have developed with the
  average embryo weighs 9 g and has a crown-rump
  length of 5 cm.

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• Fetal Period (from 9th week of gestation till
  birth)
• From the 9th week on somatic changes consists of
  increases in cell number and size and structural
  remodeling of several organs.
• By 10th week, the face is recognizably human
• By 12th week, the gender of external genitals
  becomes clearly distinguishable.
• By 20-24 weeks, primitive alveoli have formed and
  surfactant production has begun, weight 460 g ,
  crown-rump length of 19 cm.
• By 25th week weight 900 g, crown-rump length
  25cm.
• During the 3rd trimester, weigh triples and
  length doubles as body stores of protein, fat,
  iron, and calcium increases.

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• Neurologic development
• During the 3rd week, a neural plate appears ,
  infolding produces a neural tube that will become
  the central nervous system and a neural crest
  that will become the peripheral nervous system.
• By the 5th week the three main subdivisions of
  forebrain, midbrain, and hindbrain are evident,
  the dorsal and ventral horns of the spinal cord
  begun to form, along with the peripheral motor
  and sensory nerves.
• Myelinization begins at midgestation and
  continues throughout the 1st 2 years of life.
• By the end of the embryonic period the gross
  structure of the nervous system has been
  established.

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• Behavioral development
• Muscle contractions first appear around 8th week.
• By the 13-14 weeks breathing movement and
  swallowing motions appear .
• Eye opening occurs around 26 week.
• During the 3rd trimester, fetuses respond to
  external stimuli with heart rate elevation and
  body movements. Such as sudden auditory tone, but
  decreases after several repetitions.

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• Threat to fetal development
• Mortality and morbidity are highest during the
  prenatal period.
• For any potential teratogen, the extent and
  nature of it effect are determined by
  characteristics of the host as well as the dose
  and timing of exposure (the earlier the exposure
  the more complications occurring).
• Teratogens associated with gross physical and
  mental abnormalities include
• Various infectious agents (toxoplasmosis,
  rubella, syphilis)
• Chemical agents (mercury, antiepileptic
  medications, ethanol)
• High temperature.
• Radiation.

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• Physical growth parameters during
• First year of life

Weight Kilograms
At birth 3.25
3-12 months (Age(mo)9)/2
Height Centimeters
At birth 50
At 1 year 75
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• Weight
• Weight loss in the first few days, 5-10 of
  birth weight.
• Return to birth weight 7-10 days.
• Double birth weight 4-5 months.
• Triples birth weight at one year.
• Daily weight gain
• 20-30 g for first 3-4 months
• 15-20 g for the rest of first year.
• Average weight
• 3.5 kg at birth.
• 10 kg at 1 year.
• 20 kg at 5 years.
• 30 kg at 10 years.

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• Height
• At one year 50 cm.
• At one year 75 cm.
• At 4 years double birth height 100 cm.
• After that height increases with an average of
  5-6 cm/yr
• For females at time of puberty 8-10 cm/yr.
• For males at time of puberty 10-12 cm/yr.

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• Head Circumference
• At birth 35 cm.
• At 6 months 43 cm
• 1st 6 months HCC increases with an average 1.5
  cm/month.
• At one year 47 cm
• 2nd 6 months HCC increase with an average of 0.5
  cm/month.
• - For the rest of life HCC increase about 10 cm

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Growth and Caloric Requirements
Age Approximate daily weight gain (g) Growth in length (cm/mo) Growth in HCC (cm/mo) RDA (kcal/kg/day)
0-3 mo 30 3.5 2 115
3-6 mo 20 2 1 110
6-9 mo 15 1.5 0.5 100
9-12 mo 12 1.2 0.5 100
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• Chronology of Human dentition of primary and
  secondary teeth

Calcification Calcification Age of Eruption Age of Eruption Age of Shedding Age of Shedding
Begins at Complete at Maxillary Mandibular Maxillary Mandibular
Primary teeth
Central incisors 5th fetal mo 18-24 mo 6-8 mo 5-7 mo 7-8 yrs 6-7 yrs
Lateral incisors 5th fetal mo 18-24 mo 8-11 mo 7-10 mo 8-9 yrs 7-8 yrs
Canines 6th fetal mo 30-36 mo 16-20 mo 16-20 mo 11-12 yrs 9-11 yrs
First molars 5th fetal mo 24-30 mo 10-16 mo 10-16 mo 10-11 yrs 10-12 yrs
2nd molar 6th fetal mo 36 mo 20-30 mo 20-30 mo 10-12 yrs 11-13 yrs
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Calcification Calcification Age of Eruption Age of Eruption
Begins at Complete at Maxillary Mandibulat
Secondary Teeth
Central incisors 3-4 mo 9-10 yrs 7-8 yrs 6-7 yrs
Lateral incisors max.10-12 mo Mand.3-4 mo 10-11 yrs 8-9 yrs 7-8 yrs
Canines 4-5 mo 12-15 yrs 11-12 yrs 9-11 yrs
First molars Birth 9-10 yrs 6-7 yrs 6-7 yrs
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• Time of Appearance (on X ray) of Centers of
  Ossification in infancy

Bones and Epiphyseal Centers Age of Appearance
Femur, Distal Usually present at birth
Tibia, Proximal Usually present at birth
Humerus, Head Three weeks
Capitate 2 mo 2 mo
Hamate 3 mo 2 mo
Femur, Head 4 mo 2 mo

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Development during the first year of life
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Neonatal period(1st 4 weeks) Neonatal period(1st 4 weeks)
Gross motor Lies in a flexed attitudes, head sags on ventral suspension.
Fine motor Fixate face or light in line of vision, dolls eyes
Reflex Moro response, stepping, placing reflexes are active.
Social Visual preference to human faces.
At 4 weeks At 4 weeks
Gross motor Legs more extended, holds chin up,head lifted momentarily to plane of body on ventral suspension Tonic neck posture predominates, head lags on pull to sit.
Fine motor Follows moving object.
Social Beginning to smile.
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At 8 weeks At 8 weeks
Gross motor Raises head slightly further, head sustained in plane of body on ventral suspension Tonic neck posture predominates, head lags on pull to sit.
Fine motor Follows moving object 180 degree
Social Smile on social contact, coos
At 12 weeks At 12 weeks
Gross Lifts head and chest,arms extended, head above plane of body on ventral suspension. Head lags partially on pull to sit.
Reflex Typical moro reflex disappears
Social Says ahh, ngah
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At 16 weeks At 16 weeks
Gross motor Lifts head and chest, head in approximately vertical axis, no head lag on pull to sit, enjoys sitting with full truncal support. When held erect, pushes with feet.
Fine motor Reaches and grasps objects and brings them to mouth.
Social Laughs out loud, excited at sight of food
At 28 weeks At 28 weeks
Gross motor Rolls over from supine to prone and from prone to supine, pivots, crawls, Lifts head, sits briefly, on standing may support most of weight.
Fine motor Reaches out for and grasps large objects, transfer objects from hand to hand,grasp using radial palm.
Social Prefers mother, babbles
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At 40 weeks At 40 weeks
Gross motor Sits up without support, pulls to standing, walks holding on furniture, creeps or crawls.
Fine motor Grasp objects with thumb and forefinger, pokes at things with forefinger, attempts to retrieve dropped objects.
Language Repetitive consonant sounds (mama, dada)
Social Plays peek-a-boo, waves bye bye
At one year At one year
Gross motor Walks alone or with one hand held, rises independently
Language A few words beside mama, dada
Social Plays simple ball games, makes postural adjustment to dressing
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