PSY 2114 3.2 - Physical Development in Early Infancy

Stages of vaginal birth

1. Contractions leading to dilation of cervix

2. Delivery

3. Detachment and expulsion of placenta, umbilical cord, and other membranes

On average, how long does it take to deliver first-born child and subsequent children?

- 12-14 hrs for first born

- 4-6 hrs for subsequent children

when does the first stage of birth end?

when the cervix is ~10cm dilated

Delivery usually takes how long?

20-50 mins

Expulsion of the placenta usually takes how long?

5-10 mins

Neonate average length and weight

20" long and 7.5lbs

Neonate appearance

- Large head

- Short, bowed legs

- Round face, large forehead and eyes

Apgar scale use

used to assess vital signs in infant

When is the apgar usually taken?

taken 1-5mins after birth

Apgar scale acronym

A - appearance

P - pulse

G - grimace

A - activity (muscle tone)

R - respiratory effort

Apgar scores

A score from 7-10 is ideal

A score of 3 or under is an emergency

Gestational age terms

Preterm, full-term, postterm

Preterm

born before 36 weeks gestation

Full-term

born between 37 and 42 weeks gestation

Postterm

born after 42 weeks gestation

Birth weight

Low BW, very low BW, extremely low BW

Low BW

less than 2500g

Very low BW

Less than 1500g

Extremely low BW

less than 1000g

Weight is also compared with...?

gestational age

Weight percentile meaning

heavier than --% of your peers

Appropriate for gestational age (AGA)

BW between 10th and 90th percentile

Small for gestational age (SGA)

BW below 10th percentile

Large for gestational age (LGA)

BW above 90th percentile

Birth weight chart

Birth weight in singletons vs. multiples

Multiples (twins/triplets etc.) are usually smaller than singletons

Fetuses are viable after how many weeks gestation?

22 weeks gestation

- 1lb

How many fetuses survive at lowest possible viability age/weight?

9-30% survive (VERY low rate of survival)

50% of those who do survive have major disabilities

Risk factors for preterm birth

- Immature uterus (mom <20yrs)

- Poor nutrition

- Poor prenatal care

- Low SES

- Alcohol, drugs

- High BP

- Fetal malformations

- Stress

Challenges in LBW infants

- 25X more likely to die in first month

- Smaller and younger at birth: increased number and severity of problems

- Increased risk of vision/hearing loss, learning disability, epilepsy, cognitive impairments, anxiety

Factors that improve outcomes for LBW infants

- parental contact (skin-to-skin)

- good nutrition

Issues in preterm infants

- respiratory distress, death

- temperature regulation (lack of fat)

- brain bleeds, heart valve problems

Why is respiratory distress a concern in preterm infants?

Lungs are not fully developed, so they lack surfactant which leads to lung collapse

- surfactant develops ~34 weeks gestation

Kangaroo care

A 'replacement' for incubators for preterm infants, in underdeveloped countries with little access to incubators.

Baby is worn skin-to-skin to baby for 24hrs

Types of reflexes

Adaptive reflexes

Primitive reflexes

Adaptive reflexes

help newborns survive; some adaptive reflexes persist throughout life

- sucking

Primitive reflexes

controlled by primitive parts of the brain; these reflexes mainly disappear by the end of the 1st year

- moro, babinski

Common primitive reflexes

- Babinski (sole of foot)

- Grasping (palm of hand)

- Moro (loss of support, arms and legs out)

- Plantar (curls toes when object under)

- Rooting (cheek touch, opens mouth)

- Tonic neck (on back, flex one side, extend other)

What are primitive reflexes usually used for?

to assess neurological development

Two significant infant states

sleeping and crying

Sudden infant death syndrome (SIDS)

the unexplained sudden death of an apparently healthy infant under one year of age

Incidence of SIDS

1/2000 live-born babies in Canada

- rare in the 1st month

- peaks b/w 2-4 months

Disproportionately prevalent in Indigenous communities

SIDS risk factors

- LBW (< 3.5 lbs)

- Sibling died of SIDS

- Exposure to cocaine, heroin, or methadone during pregnancy

- Parental smoking

- Male

- Minor respiratory illness

- Teen mom with previous children

- Short interval between pregnancies (recommended: wait >1 year between pregnancies)

Reducing the risk of SIDS

- healthy pregnancy (increases BW)

- Breast-feed babies whenever possible (antibodies in colostrum)

- No objects in crib

- No smoke

- put babies to sleep on their BACK

Back to Sleep Campaign

Encourage parents to put babies to sleep on back to reduce SIDS risk

Why does stomach sleeping increase risk of SIDS?

Infants are more likely to re-breathe the air they have just exhaled, which can raise their levels of carbon dioxide

Physical skills present at birth (3)

- Looking

- Sucking

- Crying

Looking

infants can direct head and eyes to look at particular stimuli

Sucking

- Quite complex; some babies need practice

- Means of exploration

- Buffers against pain

Why is sucking more than a simple reflex?

- Stops with distraction (visual or auditory stimulus)

- Varies with conditions (changes if amount or type of fluid available changes)

- Can be used to control access to stimuli (non-nutritive sucking paradigm)

Crying

- Complex

- Different types (parents can't actually tell)

- Survival mechanism

- crying method can follow accents

Early motor development

- Postural and locomotor development (control of trunk of body, moving around)

- Prehension (using hands to do tasks)

Patterns of early development

- Proximodistal

- Cephalocaudal

Proximodistal development

Centre of body is controlled before extremities

- Ex: Babies can control their hand before their digits

Cephalocaudal development

Development moves from head to toe

- Ex: Babies can sit up before they stand up

Postural and locomotor milestones...?

have a huge range in what is considered typical