Gestational age assessment and Neonatal Reflexes

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Dr. Kalpana MallaMD Pediatrics

Manipal Teaching Hospital

Gestational Age Assessment:

Estimating post-conceptual age of the neonate

• An accurate assessment of age is important for 2 reasons– Age and growth patterns appropriate to that age

aid in identifying neonatal risks– Help in developing management plans

Gestational AgeAssessment

• There are 3 general methods to determine gestational age– Calculation of dates based on LMP– Evaluation of obstetrical patterns– Physical exam of the neonate

– Assessment of neuromuscular and physical criteria by inspection and palpation

Modified Ballard

Plotting Weight, Length, HC

Neuromuscular Criteria

• Posture– Observe in the supine position– Score is assigned based on the degree of flexion of

arms, knees and hips– Increased flexion and hip adduction with

increased gestational age

Neuromuscular Criteria

• Square Window– Infants hand is flexed on the forearm between the thumb

and index finger of the examiner– Apply enough pressure to get FULL flexion without rotating

the wrist– Angle between the forearm and hypothenar eminence of

palm is measured

Neuromuscular Criteria

• Arm Recoil– Flex the neonates arms for 5 seconds while in the supine

position– Fully extend the arms by pulling on the hands and release– The degree of arm flexion and strength of recoil are

scored

Neuromuscular Criteria• Popliteal Angle

– Place infant in supine position with the pelvis on the mattress

– Using the thumb and index finger of one hand, examiner holds the knee adjacent to the chest and abdomen. Gently extend the leg with the index finger

– Look at the angle between the lower leg, thigh and posterior knee

Neuromuscular Criteria

• Scarf sign– Place infant in supine position with head in mid-line

position.– Grasp the infants hand and pull the arm across the chest

and around the neck.– Look at the relationship of elbow to mid-line of body when

arm pulls across the chest

Neuromuscular Criteria

• Heel to ear– Place the infant supine with pelvis flat on table.– Grasp one foot with thumb and index finger and

draw foot as near to head as possible.– Note the distance between the foot and head as

well as degree of knee extension

Physical Criteria

• Skin– less transparent and tougher

with increasing gestational age

– 36-37 weeks loses transparency and underlying vessels are no longer visable

– Increasing gestational age the veins become less viable and increasing subcutaneous tissue

Physical Criteria

• Lanugo– Fine downy hair covering fetus from 20-28 weeks– Disappears around face and anterior trunk ~28

weeks– Term infants may have a few patches over

shoulders

Physical Criteria• Sole creases

– 28-30 weeks appear and cover the anterior portion of of the plantar surface of the foot

– Extend toward the heel as increases gestational age

– After 12 hours sole creases are not valid indicator of gestational age due to drying of the skin

Physical Criteria

• Breast tissue and areola– Areola is raised by 34

weeks– A 1-2 mm nodule of

breast tissue is palpable by 36 weeks

– By 40 weeks the nodule is 10mm

Physical Criteria

• Ears– Incurving of the upper pinna begins by 34 weeks

gestation and extend entire lobe by 40 weeks– Before 34 weeks, pinna has very little cartilage

(Stays folded on itself)– At 36 weeks, there is some cartilage and will

spring back

Physical Criteria

• Female Genitalia– Early gestation, clitoris

prominent and widely separated labia

– By 40 weeks, fat deposits have increased in size in labia majora so labia minora are completely covered

Physical Criteria

• Male genitalia– Testes begin to descend from abdomen around 28

weeks– At 37 weeks, testes can be palpated high in

scrotum– At 40 weeks, testes are completely descended and

covered with rugae– As gestation progresses, scrotum becomes more

pendulous

CANSCORENine signs for assessing nutritional status in term infants

• Hair• Cheeks• Chin & neck• Arms• Back

• Buttocks• Legs• Chest• Skin on

Abdominal wall

Gestational Age Assessment

• Physical Assessment– Assessment of anterior vascular lens capsule using

opthalmoscope• Best done on the 2nd day of life

– Assessment of neuromuscular and physical criteria by inspection and palpation

Neonatal reflexes or primitive reflexes

• Definition – inborn behavioral patterns that develop during uterine life.

• They should be fully present at birth and are gradually inhibited by higher centers in the brain during the first three to 12 months of postnatal life.

Neonatal reflexes or primitive reflexes

• Essential for a newborn's survival immediately after birth - sucking, swallowing, blinking, urinating, hiccupping, and defecating.

• Neonatal reflexes represent important reactions of the nervous system

Moro reflex

• Elicited by the sudden downward movement of the head and release it - symmetric extension and abduction of the arms and opening of the hands, followed by flexion of the upper extremities in an embracing movement

• Present at birth and disappears by 3-4 months.

Startle reflex Elicited - infant lying in a supine position and is stimulated by a sudden

loud noise that causes rapid or sudden movement of the head - results in a symmetrical extension of extremities while forming a C shape with the thumb and forefinger. This is followed by a return to a flexed position with extremities against the body.

Disappears - third to the sixth month.

- An asymmetrical reflex may indicate- fractured clavicle or a birth injury to the nerves of the arm. Absence of this reflex - underlying neurological damage.

Rooting reflex

• Elicited by applying light tactile stimulation in the perioral area- responds by turning the head toward the stimulus, opening the mouth and searching for the stimulus.

• Inhibited by the third to fourth month.

Sucking

• Elicited by placing a gloved finger or a nipple in the infant's mouth. The normal term infant has a strong, coordinated, and symmetric suck.

• Disappears at three to four months

Grasping reflex

palmar reflex -when a finger is placed in the neonate's palm and the neonate grasps the finger plantar reflex -

Palmar grasp

• Elicited by stroking or applying pressure to the infant's palm with the examiner's finger - The grasp tighten with attempts to remove the finger

• Weakens at three months; disappears around the sixth month

Plantar grasp

- Elicited by placing a finger against the base of the neonate's toes and the toes curl downward to grasp the finger.

- - Disappear by 9-12 months

Stepping reflex / Walking

• Elicited by holding the infant in an upright vertical position and gently touching the feet to a flat surface - infant's feet move in an alternating stepping motion

• Disappears by 2-3 months, until it reappears as he learns to walk at around 10-15 months

Placing reflex

- Elicited by contact of the dorsum of the foot with the edge of a table -

• the foot is lifted and placed on a table's surface

Asymmetrical tonic neck reflex / fencer response

Also called- tonic labyrinthine reflex Elicited by turning the head to one side. As

the head is turned, the arm and leg on the same side will extend while the opposite limbs bend

Present at birth and disappears by six months

Symmetrical tonic neck reflex

Occurs with either the extension or flexion of the infant's head. Extension of the head results in extension of the arms and flexion of the legs, and a flexion of the head causes flexion of the arms and an extension of the legs.

- Inhibited by the sixth month to enable crawling

Babinski or plantar

• Reflex is triggered by stroking one side of the infant's foot upward from the heel and across the ball of the foot - responds by hyperextending the toes; and the other toes fan outward

• Disappears at nine months to a year

Blink reflex

Is stimulated by momentarily shining a bright light directly into the neonate's eyes - blink.

This reflex should not become inhibited - Permanent

Pupillary reflex

Occurs with darkening the room and shining a penlight directly into the neonate's eye for several seconds. The pupils should both constrict equally;

- this reflex should not disappear- permanent

Galant reflex

Elicited by placing the infant on the stomach and you stroke neck to the spinal cord (paravertebral area) on his middle to lower back, it will cause his back to curve towards the side that you are stroking.

Present at birth and disappears by 3-6 months.

Positive Support Reflex

• Like the stepping reflex, if the baby is held under his arms, support his head, and allow his feet to bounce on a flat surface, he will extend (straighten) his legs for about 20-30 seconds to support himself, before he flexes his legs again and goes to a sitting position

• Disappears by 2-4 months

Prone crawl reflex

Elicited by placing the neonate prone (face down) on a flat surface. The neonate will attempt to crawl forward using the arms and legs.

- Inhibited by three to four months of age.

Doll's eye reflex

Elicited by infant supine (lying on the back) and slowly turning the head to either side. The infant's eyes will remain stationary

- Disappear between three to four months of age.

Common Problems

• Presence and strength of a reflex - indication of neurological functioning• Absent or abnormal reflex - suggest significant neurological problems• The primary reflex system is inhibited or transformed in the first year of

life and a secondary or postural reflex system emerges• The secondary system forms the basis for later adult coordinated

movement• Severe persistence of primary reflexes - predominantly persistent physical

problems. • The process of inhibition of these reflexes in the earliest months of life

remains unknown.

Postural reactions

• Usually begin later in the first year of life. These postural reactions include:

Derotational Righting

Parachute ResponsePropping

Derotational Righting

• This reaction usually appears by 4-5 months, and involves your infant's body turning to follow the direction of his head when it turns, helping him learn to roll over.

Parachute Response

• This is a protective response that protects your infant if he falls. Beginning at about 5-6 months, if an infant falls, he will extend his arms to try and 'catch' himself.

Propping

• This responses help a child learn to sit• Anterior propping response - begins at 4-5 months, and

involves the infant extending his arms when he is held in a sitting position, allowing him to assume a tripod position

• Lateral propping - appearing at 6-7 months, causes him to extend his arm to the side if he is tilted

• Posterior propping, causing him to extend his arms backwards if he is titled backward

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