4-8 months
4–8 months
Physical
Physical
- Head and chest circumferences are basically equal.
- Head circumference increases approximately 1 cm per month until six to seven months, then 0.5 cm per month; head circumference should continue to increase steadily, indicating healthy, ongoing brain growth.
- Posterior fontanelle closing or fully closed.
- Anterior fontanelle.
- Breathing is abdominal; respiration rate depending on activity; rate and patterns vary from infant to infant.
- Teeth may begin to appear, with upper and lower incisors coming in first. Gums may become red and swollen, accompanied by increased drooling, chewing, biting, and mouthing of objects.
- Legs may appear bowed; bowing gradually disappears as infant grows older.
- Fat rolls ("Baby Fat") appear on thighs, upper arms and neck.
- True eye color is established.
- Reflexive behaviors are changing:
- Blinking reflex is well established
- Sucking reflex becomes voluntary
- Moro reflex disappears
- When lowered suddenly, infant throws out arms as a protective measure.
- Swallowing reflex appears and allows infant to move solid foods from front of mouth to the back for swallowing.
- Picks up objects using finger and thumb (pincer grip).
- Reaches for objects with both arms simultaneously; later reaches with one hand or the other.
- Transfers objects from one hand to the other; grasps object using entire hand (palmar grasp).
- Handles, shakes, and pounds objects; puts everything in mouth.
- Able to hold bottle.
- Sits alone without support, holding head erect, back straightened, and arms propped forward for support
- Pulls self into a crawling position by raising up on arms and drawing knees up beneath the body; rocks back and forth, but generally does not move forward.
- Lifts head when placed on back.
- Can roll over from back or stomach position.
- May accidentally begin scooting backwards when placed on stomach; soon will begin to crawl forward.
- Looks for fallen objects by 7 months
- Plays ‘peek-a-boo’ games
- Cannot understand “no” or “danger”