psychomotor and physical development of infant


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Related to psychomotor and physical development of infant: Cognitive development

psychomotor and physical development of infant

The physical growth of an infant and the effect of mental activity on motor skills. It is important that all concerned with the care of the newborn through infancy have guidelines for comparing the growth and development of an individual with normal standards. Certain activities of infants serve as general indicators of normal psychomotor development. The average ages for certain of these activities are shown in the accompanying table. See: table; arousal level

Appearance and loss of certain reflexes and reactions: The Moro reflex is present at birth and disappears by 3 to 6 months; the stepping and placing reflexes are present at birth and are no longer obtainable by 6 weeks; the tonic neck reflex is usually present at 2 months and is gone by 6 months; neck righting appears at 4 to 6 months and is gone by 24 months; the parachute reaction is present at 9 months and persists; sucking and rooting are present at birth and are usually gone by 4 months if tested while awake and by 7 months if tested while the infant is asleep; palmar grasp is present from birth to 6 months; plantar grasp is present from birth to 10 months.

Physical Development
Length RangeWeight Range
InCmLbKg
Birthboys18¼–21½46.4–54.45½–9¼2.54–4.15
girls17¾–20¾45.4–52.95¼–8½2.36–3.81
1 Monthboys19¾–2350.4–58.67–11¾3.16–5.38
girls19¼–22½49.2–56.96½–10¾2.97–4.92
3 Monthsboys22¼–25¾56.7–65.49¾–16¼4.43–7.37
girls21¾–2555.4–63.49¼–14¾4.18–6.74
6 Monthsboys25–28½63.4–72.313¾–20¾6.20–9.46
girls24¼–27¾61.8–70.212¾–19¼5.79–8.73
9 Monthsboys26¾–30¼68.0–77.116½–247.52–10.93
girls26–29½66.1–75.015½–22½7.0–10.17
12 Monthsboys28¼–3271.7–81.218½–26½8.43–11.99
girls27½–31¼69.8–79.117¼–24¾7.84–11.24
Psychomotor Development
Birth through 1st MonthAbility to suck, swallow, gag, cry, and maintain eye contact with a person. Head needs to be supported. Loud noises may cause a startle reflex.
2nd MonthMay turn to either side when on their backs; will follow moving objects; able to lift head but not for a sustained period; begin to smile, frown, and turn away.
3rd MonthGreater movement and vocal response to stimuli; notice own hands and suck on them; head steady while supported.
4th and 5th MonthsAble to lift head higher when lying on stomach; will reach for objects and may be able to encircle a bottle with both hands; may drool a lot; attempt to put all kinds of objects in mouth.
6th–9th MonthDevelop ability to grasp and pick up food; are able to pull up to a sitting position and eventually will crawl; begin to make noises that sound like words and to recognize certain words; will play peek-a-boo.
9th–11th MonthDevelop ability to handle food and to drink from a cup; may imitate sounds and say certain words; crawl by pulling body along with arms, and pull themselves to a standing position; they will point at objects and throw things; they want to feed themselves and to help with dressing and undressing; they will walk while holding a person's hand.
12th MonthCan eat food alone and drink from a cup with assistance; able to move around easily and crawl up stairs and out of crib.