When describing infant development, tasks are generally categorized into the following headings: Gross motor (examples are head control, sitting, walking), fine motor (examples are holding a spoon, pincer grasp), sensory(sight, hearing, etc.), language, and social.

The physical development of the infant begins at the head, then progresses to other parts of the body (for example, sucking comes before sitting, which comes before walking).

Physical milestones:

• newborn through 2 months
  • The infant can lift and turn the head when lying on its back.
  • The neck is unable to support the head when pulled to a sitting position.
  • The hands are fisted, the arms are flexed.
  • Primitive reflexes are in full operation. These include:
    • rooting and sucking -- turns head in search of nipple when cheek is touched and begins to suck when nipple touches lips.
    • tonic neck response -- left leg extends when infant gazes to the left, while right arm and leg flex inward, and vice versa.
    • palmar hand grasp -- infant closes its hand and "grips" your finger.
    • plantar grasp -- infant flexes the toes and forefoot.
    • Babinski reflex -- toes fan outward when sole of foot is stroked.
    • Moro reflex -- extends arms then bends and pulls them in toward body.
    • placing -- leg extends when sole of foot is stimulated.
    • stepping and walking -- takes brisk steps when both feet placed on a surface, with body supported.
• 3 through 4 months
  • Primitive reflexes have either already disappeared, or are in the process of doing so.
  • Hand and feet actions begin to come under willed control, but are by no means fine-tuned. The infant may begin to use both hands, working together, to accomplish desired effects. The infant is still unable to coordinate the grasp, but swipes at objects to bring them closer.
  • The infant raises up (upper torso, shoulders, and head) with arms when lying face down (on his tummy).
  • Neck muscles are developed enough to allow the infant to sit, with support, and keep head up.
  • Enhanced eye-muscle control allows the infant to track objects.
  • Increased acuity of vision allows the infant to distinguish objects from backgrounds with minimal contrast (such as a button on a blouse of the same color).
• 5 through 6 months
  • The infant begins to grasp blocks or cubes using what's called the ulnar-palmar grasp technique (pressing the block into palm of hand while flexing or bending wrist in). Does not yet use thumb opposition.
  • The infant rolls from back to stomach. When on tummy, the infant can push up with arms to raise the shoulders and head above surface and look around or reach for objects.
  • Able to sit alone, without support, for only moments initially and then up to 30 seconds or more.
• 6 through 9 months
  • The infant is able to sit steadily, without support, for long periods of time.
  • The infant may pull into and maintain a standing position while holding onto furniture.
  • The infant can walk while holding the hand of an adult.
  • The infant learns to sit down from a standing position.
• 9 through 12 months
  • The infant begins to balance while standing alone.
  • The infant takes steps and begins to walk alone.

SENSORY DEVELOPMENT

• Vision -- the newborn infant can see within a range of 8-12 inches, color vision develops between 4-6 months, by 2 months can track moving objects up to 180 degrees, and prefers faces.

• Hearing -- begins prior to birth, and is mature at birth. The infant prefers frequencies of the human voice.

• Touch, taste, smell -- mature at birth; prefers sweet taste.

• Vestibular (inner ear) senses -- the infant responds to rocking and changes of position.

LANGUAGE DEVELOPMENT

Crying is a vitally important means of communication. By the third day of life, mothers can distinguish their baby's cry from others. By the first month of life, most parents can tell if their baby's cry means hunger, pain, or anger. Crying also elicits a nursing mother's milk letdown. The inherent biological response in most humans to crying insures the infant's survival.

The amount of crying in the first 3 months varies in a healthy infant between 1 to 3 hours a day. Infants who cry more than 3 hours a day are often described as having colic.

Colic in infants is rarely due to a physiologic problem. It may also be associated with overanxious mothers.

Excessive crying can be associated with child abuse. Regardless of the cause, it is a complex problem that deserves a medical evaluation.

BEHAVIOR

The behavior of the newborn is characterized by six states of consciousness: quiet sleep, active sleep, drowsy waking, quiet alert, fussing, and active crying. The ability to move smoothly from one state to another is one of the most reliable signs of neurologic maturity and integrity. Heart rate, breathing, muscle tone, and body movements vary with each state.

Many physiologic functions are not stable in the first months after birth. This variability is normal and differs from infant to infant. Temperature control, skin color, stooling, yawning, gagging, hiccupping, and vomiting are easily affected by stress and stimulation.

Periodic breathing, in which breathing starts and stops again, is normal and is not a sign of SIDS (sudden infant death syndrome). Some infants will vomit after each feeding, but have nothing physically wrong with them. They continue to gain weight and develop normally.

Other infants grunt and groan distressfully while stooling but produce soft, blood-free stools and growth and feeding remain good. This is due to immature abdominal muscles used for pushing, and does not require any intervention.

Sleep/wake cycles are extremely variable and do not stabilize until 3 months old. These cycles occur in random intervals of 30-50 minutes at birth and gradually increase as the infant matures. By 4 months old, most infants will have one 5-hour period of uninterrupted sleep.

Breast-fed infants will feed about every 2 hours. Formula-fed infants should be able to go 3 hours between feedings. During periods of rapid growth, they may feed more frequently.

Giving the child water is not necessary! An infant receiving adequate hydration will produce 6-8 wet diapers in a 24-hour period. Teaching the infant to suck a pacifier or his or her own thumb provides comfort between feedings.

SAFETY

Safety is very important for infants. It is very important to consider their developmental stage. For example, around 2-3 months of age, the infant begins to roll over. Therefore, extreme caution must be taken while the baby is on the changing table. Consider the following important safety tips:

• Place infant in a proper car seat in every car ride, no matter how short the distance. A car seat that faces backwards should be used until the infant is at least a year of age or longer if possible, then a forward facing car seat can be used safely. The safest place for the infant's car seat is in the middle of the back seat. It is vitally important for the driver to pay attention to driving -- not playing with the infant. If an infant needs assistance, safely pull the car over to the shoulder and park prior to trying to help the infant.
• Do not leave an infant alone with siblings or pets. Even older siblings are seldom prepared to handle the potential emergency situations that may arise. Pets, even though they may appear to be gentle and loving, may react unexpectedly to an infant's cries or grabs or may actually smother an infant by lying too closely.
• Do not leave an infant unattended on a surface from which the child can wiggle or roll over and fall off.
• Use gates on stairways, and block off rooms that are not "child proof" -- remember, infants may learn to crawl or scoot as early as 6 months.
• Do not drink or carry anything hot while holding the infant, to avoid burning the infant -- infants begin waving arms and grabbing for objects at 3 to 5 months.
• Do not allow older infants to crawl or walk around in the kitchen while adults or older siblings are cooking. The kitchen can be blocked off with a gate or the infant placed in a playpen, highchair, or crib while others cook.
• Never leave small objects within an infant's reach -- infants explore their environment by placing everything they can get their hands on into the mouth.
• Know how to handle a choking emergency in an infant by taking a certified course through the American Heart Association, the American Red Cross, or a local hospital.
• Be aware of potential poisons (household cleaners, cosmetics, medications, even some plants) within your home and keep them out of the infant's reach. Use drawer and cupboard safety latches. Know the number (and keep it posted near the phone) of your local Poison Control Center. Have a bottle of syrup of ipecac available in your home in case accidental poisoning occurs, but remember to call poison control first and use ipecac only if directed to do so by the poison control representative.
• For the first 5 months of life, always place your infant on his or her back to go to sleep. This position has been shown to reduce the risk of SIDS (sudden infant death syndrome). Once a baby can roll over by himself, the risk of SIDS is greatly reduced by the maturation of the nervous system.

CALL HEALTH CARE PROVIDER IF:

• the infant does not look good; looks different from normal state; not consolable by holding, rocking, or cuddling.
• the infant's growth or development does not appear normal.
• your infant seems to be "losing" developmental milestones. For example, if your 9 month old was able to pull to standing, but at 12 months is no longer able to even sit unsupported.
• you are concerned at any time.