Fetal development

Question 1

When are the terms embryo and fetus appropriate

Answer 1

Embryo is appropriate until 8 weeks of gestation, and then at week 9, becomes a fetus

Question 2

When is it considered structurally complete

Answer 2

Week 8

Question 3

Fetal weeks 9-12

Answer 3

Genitals well differentiated
Tooth buds appear
Cerebellum develops
Red blood cells produced by liver
Growth of all existing structures

Question 4

Fetal weeks 13-16

Answer 4

Skin is almost transparent
Lanugo develops on the head
Meconium is made in the intestines
Muscles and bones develop, bones are still soft
Sucking motions are made with the mouth

Question 5

Fetal weeks 17-19

Answer 5

Can hear
Mother can feel movement
Spinal cord myelination begins
Eyebrows and lashes form
Nails form; at 20 weeks, sensory portion of auditory system (inner ear) has attained adult shape

Question 6

Trimester weeks

Answer 6

First trimester: conception through week 13
Second trimester: week 14 through 26
Third trimester: week 27 to 40

Question 7

Fetal week 21-23

Answer 7

Fetal heartbeat can be heard with a stethoscope
Bone marrow makes blood cells
Fat is stored

Question 8

Weeks 23-24

Answer 8

Lower respiratory system develops but still no surfactant

Question 9

50% chance of survival

Answer 9

Between 23rd and 25th week, then survival increases

Question 10

23 to 24 weeks gestational age at birth

Answer 10

Lung viability depends on surfactant- not yet present, provide in NICU
Survival Depends on weight, family values and beliefs
Slow active movement of hands to face
Very sporadic flailing movement patterns

Question 11

24 weeks gestation

Answer 11

All eye parts present

Foot and handprints form

Question 12

25-28 weeks

Answer 12

Rapid brain development
Eyelids open and close
Gas exchange is weak but present

Question 13

27 to 28 weeks outside womb motor patterns

Answer 13

Resting postures:
– Generalized hypotonia • Resistance to passive movement:
– Full PROM
– Grasp response elicits only
the arm back into flexion – No attempt to align head and
body with pull to sit (PTS) – No placing response
• Active motor patterns:
– Spasmodic and random flailing
No t for reproduction or redistribution
flexion of the fingers without activation of the wrist and arm
– No resistance in heel to ear
– Popliteal angle: 180 degrees
– Scarf sign, no attempt to recoil

Question 14

28 weeks gestation outside womb oral motor

Answer 14

Weak but present non-nutritive suck (NNS) • Rooting reflex long latency period, slow response to
oral stimulation:
– Mouth opening only may be seen

Question 15

Fetal development 29-32 weeks

Answer 15

Body fat deposited rapidly
Rhythmic breathing movements
Begins to store calcium and iron

Question 16

29 weeks gestational age outside womb motor

Answer 16

Resting postures:
– More variability in postures; remains hypotonic • Resistance to passive movement:
– Full PROM; movement of one extremity may elicit movement in the
opposite extremity – Moro incomplete but symmetrical – No resistance in the scarf sign; elbow crosses midline; may move UE back
to the same side of the body after placing – In prone, the infant attempts physiological flexion by moving LEs into a
flexed posture – Complete head lag; attempt to right head once anteriorly placed in
supported sitting – Mild active knee flexion with eliciting of the placing response – Stepping response is elicited with mild neonatal support

Question 17

29 weeks active motor patterns

Answer 17

Slow, jerky, random flailing – Reflexive movements in response to handling – LE predominate motor patterns; LE presenting in the
beginning of the physiological flexion patterns

Question 18

28 to 30 weeks vision

Answer 18

Increases in waking phases • Eyes remain closed for the majority of the time • Doll’s eye reflex may be observed 1 • Saccadic eye movements:
in apnea or brady
– Rapid – Intermittent – Jerky
• Visual stimulation may increase stress levels and result

Question 19

30 weeks motor pattern after birth

Answer 19

Resting postures:
– Flexion of the hips and knees • Resistance to passive movement:
– Grasp response with initial flexion of the wrist and knee; the traction
response begins to elicit the lifting of the infant off the support surface – Beginning resistance in heel to ear – Scarf sign attempts to recoil the arm back into flexion – Once in supported sitting, the infant attempts anterior and posterior
righting of the head when displaced posteriorly or anteriorly – Minimal to no attempt WB through LEs in neonatal stance, but the feet do
elicit a response against the support surface
• Active motor patterns:
– Whole extremity movement with attempt to bring to midline

Question 20

30 weeks hearing

Answer 20

Th e middle ear at 30 weeks:
No t for reproduction or redistribution
– Transmission portion – Development complete – Once respiration occurs at birth, then air enters the
middle ear cavity

Question 21

31 weeks motor after delivery

Answer 21

Resting postures:
righting reaction anterior and posteriorly – No active WB through LE with neonatal
• Active movements:
– Active flexion and extension patterns against gravity
remain random and uncoordinated
No t for reproduction or redistribution
– Physiological flexion seen in the LEs • Resistance to passive movement:
– Resistance to PROM in the LEs; decrease in heel to ear
– Attempts to maintain head in midline with body in PTS;

Question 22

32 weeks motor

Answer 22

Resting postures:
– Increase in physiological flexion; knees and hips have no
resistance in heel to ear
• Active movements:
– Increase in purposeful movements
– Hand to mouth for self calming

Question 23

32 weeks motor resistance to passive movement

Answer 23

Re sistance to passive movement:
No t for reproduction or redistribution
– Increase in activation of the wrist, forearm, and arm (UE
traction response) – Popliteal angle: 150 degrees – Dorsiflexion angle: 40 to 50 degrees – PTS increase attempt to align head in midline with body – Begin eliciting WB in neonatal stance; extension of the
knee (leg onto the thigh) and attempt to extend trunk on
pelvis – Moro reflex with complete extension and adduction;
extension of the fingers

Question 24

32 weeks oral motor

Answer 24

Stronger sequencing of
NNS • Rooting complete with
mouth opening and
turning of the head
toward oral stimuli

Question 25

30 to 32 weeks vision

Answer 25

Increase in ability to maintain awake alert state • Pupillary light reflex • Monocular vision • Bright light causes immediate closing of eyes • Focus on visual stimuli for short periods • All other body movements stop when the visual system
is engaged • No preference of visual patterns • Horizontal visual tracking from midline for short
distances

Question 26

33 weeks motor

Answer 26

Resting postures:
– Continued increase in flexion of the LEs with knees and hips • Resistance to passive movement:
– Knee flexion stronger; decrease in heel to ear
– Recoil and traction response of (B) U/LEs
– PTS stronger attempt to right the head anteriorly with the body; once
displaced anteriorly or posteriorly, attempts to right the head to midline – Supportive stance, WB on LEs with trunk and knee extension; attempts to
right the head with the trunk as well – Palmar grasp +
• Active movements:
– Spontaneously flexes and extends U/LEs; smoother motor patterns but
they remain random and flailing – Ability to bring hands to the mouth for self calming

Question 27

When does surfactant develop

Answer 27

34 weeks

Question 28

34 weeks motor patterns

Answer 28

Resting postures:
– Physiological flexion, excessive ER and ABD “frogged
position”
• Active movements:
– Active vigorous flexion and extension of LEs; increase in
purposeful and reciprocal movements against a boundary – Activation of the lumbosacral joint

Question 29

34 weeks resistance to passive movement

Answer 29

Grasp and UE reaching into the scapulo-humeral joint; the
trunk can be raised off the support surface – Physiological flexion of the LEs with full flexion posture – Popliteal angle: 110 degrees – Attempting to right the head in supported sitting in all directions – Placing response elicited – Hips and knees extended in a supportive stance; beginning of
trunk activation – Ventral suspension elicits flexion of the elbows and knees with
very small effort to lift the head against gravity – Moro extends and abducts, followed by partial flexion and
adduction

Question 30

34 weeks oral motor

Answer 30

Grasp and UE reaching into the scapulo-humeral joint; the
trunk can be raised off the support surface – Physiological flexion of the LEs with full flexion posture – Popliteal angle: 110 degrees – Attempting to right the head in supported sitting in all directions – Placing response elicited – Hips and knees extended in a supportive stance; beginning of
trunk activation – Ventral suspension elicits flexion of the elbows and knees with
very small effort to lift the head against gravity – Moro extends and abducts, followed by partial flexion and
adduction

Question 31

35 weeks vision

Answer 31

Tracking horizontal past midline • May track vertical • Visual preference beginning:
– Faces – Contrasting colors

Question 32

35 weeks fetal development

Answer 32

Brain myelination begins and continues until 1 year gestational age

Question 33

36 weeks fetal development

Answer 33

Lanugo begins to disappear

Question 34

35 weeks motor patterns

Answer 34

Resting postures:
– Increase in physiological flexion; more flexion of both U/LEs against gravity
• Resistance to passive movement:
– Moro partially complete; extension and abduction with flexion and
• Active movements:
– Alert periods; active transition to alerting state prior to feeding; attempting
to self calm with hands to the mouth and/or facial area
No t for reproduction or redistribution
adduction – Increase resistance to PROM LE over UE – Prone with head in midline; active rotation of head to both directions – PTS righting of the head and attempts to maintain the head in alignment
with the body – Increase active WB through LEs in supported stance; knees and hips
extended; trunk and head attempting to maintain alignment

Question 35

37 to 40 week fetal

Answer 35

Small breast buds appear on both sexes due to mom’s hormones
At 40 weeks: Full-term and adequate surfactant to sustain life; all primitive reflex patterns are present and symmetrically elicited in the full-term infant

Question 36

36 to 37 weeks motor

Answer 36

Resting postures:
– Increased variety of resting postures
– Physiological flexion in trunk and extremities • Resistance to passive movement:
– All newborn primitive reflexes are elicited
– Traction/grasp response is elicited; the trunk and head maintain
No t for reproduction or redistribution
alignment with the body, but are unable to sustain the flexion – Moro is complete – Resistance to knee extension and hip extension and abduction – Quicker recoil / flexor withdrawal – Attempt to maintain head in alignment with the body in PTS – In the prone position, the infant’s hips are high, with the knees
under the pelvis – Stepping and placing responses

Question 37

36 to 37 weeks active movement

Answer 37

– Variability in resting postures – Active movements are more resistant by physiological
flexion – Active hands to mouth