Physical Development in Infancy

Where should babies sleep?

Attachment parenting proponents insist baby should sleep in "family bed" until h/she decides to sleep in own bed to foster a sense of security, which will ultimately lead to independence. Called "co-sleeping" Opponents believe child should learn to fall asleep in own bed; baby must be taught to put self to sleep or they will always depend on parents (or others). Independence must be taught from an early age.

Malnutrition

40-60% of world's children are malnourished. Marasmus—a wasted condition caused by a diet low in all nutrients. Appears in first year of life because Mother is too malnourished to produce healthy breast milk. Baby starves and is in danger of dying.

Colic

A period of sustained, uncontrollable crying that differs from normal crying. Crying must last for 2-3 hours at a time on a daily/almost-daily basis for at least 3 weeks to be considered colic. Usually begins during the 2nd or 3rd week of life and lasts until about 3 months Baby with colic is inconsolable and appears to be in pain. Acts hungry but can't or won't eat. Eating and sleeping are upset by colic. Rejected theories: Babies cry to exercise their lungs They cry because of gastric discomfort triggered by food allergies or sensitivity They cry because of parental inexperience Colic is hereditary Colic is more common in babies whose mothers had difficult pregnancies or deliveries Possible theories: Crying is a normal manifestation of a baby's physiological immaturity, and colic is just an extreme form of it. Immature digestive tract may contract violently when gas is passed, causing pain. Painful intestinal spasms occur because of progesterone withdrawal as maternal hormones in baby's body drop off. Immature nervous system hasn't yet learned to inhibit unwanted behavior (crying). Most plausible theory: Babies with colic lack a "calming reflex" that other babies are born with. Can't shut out sensory experiences. During first month (when colic is relatively rare), newborns have a built-in blocking mechanism that allows them to shut out stimuli. Around the 1 month mark, the mechanism disappears, and they may have a hard time adjusting to the new sensations of life.

Dynamic systems theory

A theory that says that infants assemble motor skills for perceiving and acting. They perceive something in the environment that motivates them to act. Then they use their perceptions to fine-tune their movements. Motor skills, therefore, represent solutions to the infant's goals. Motor development is not a passive process in which genes control which skills are learned in which sequence; the infant actively puts together a skill to reach a certain goal. Nature and nurture work together.

Height and weight changes

At birth, the typical baby is 7.5 lbs. and 20 inches long. First year of life: babies grow 10-12 inches and triple their body weight. By age 2 for girls & 2.5 for boys, toddlers are roughly half as tall as they will be as adults. 2-year-olds still have proportionately larger heads than adults do because toddlers have nearly full-sized adult brains to go with their small bodies. (Cephalocaudal trend of development)

Vision

All senses are fairly well-developed at birth except for vision. Newborn's visual acuity is about 20/600 because the visual centers in the brain are not fully formed yet, nor are the structures of the eye. Color vision doesn't occur until baby is 1-2 months old. Vision improves remarkably by 4 months. 6 months: visual acuity is about 20/40. Depth perception develops by 3-4 months of age.

Neurological changes at birth

Brain stem controls the 27 reflexes Medulla and midbrain are the two more highly developed brain structures. They regulate vital functions (heartbeat, respiration, attention, sleeping, waking, elimination, and head and neck movements). Least-developed part of the brain is the cortex, the gray matter that is involved in perception, body movement, thinking, and language.

Feeding the baby

Breast milk has been the standard for all of human history. With the advent of formula, breast-feeding declined from the 1940s to 1970s, when over 75% of American children were formula-fed. Today, about 2/3 of American women leave the hospital breastfeeding, but the figure drops to 30% still breast-feeding 6 months later. Breast-feeding is more common in higher SES groups, although U.S. rates are highest among Latino moms (80%). Worldwide, only half of all infants are breastfed for even a short time (UNICEF, 2014)..

Feeding cont.

Breast milk is clearly better for the baby when looking at worldwide trends, and the baby likes the taste of breast milk better, too. Main research conclusion on studies done worldwide: Breastfeeding is crucial in developing countries where disease risk is high & infants may not receive needed vaccinations (breastfeeding may be literally a matter of life and death), but in developed countries, the advantages of breastfeeding are relatively small (Colen & Ramey, 2014). If you choose to feed the baby formula, h/she will still be getting excellent nutrition and won't suffer any damage. Feeding is NOT the primary ingredient to having a happy, healthy baby.

Why bottlefeed

Breast-feeding is hard work and has some disadvantages to the mother. It's not easy to learn to breastfeed. It can be painful, too. Nursing moms often have to nurse "around the clock." Baby eats every 1 ½ hours or so instead of every 3-4 hours like formula-fed babies do. Mom is solely responsible for feeding—can't get help from others unless she pumps. Mother must watch her diet and medication use just as she did while pregnant. Less freedom for her. It's draining and exhausting, which can lead to postpartum depression. Interferes with sex in several ways: 1) no sex drive; 2) no vaginal lubrication; 3) breasts leak milk during sex Nipples can become sore and cracked. Mom runs danger of developing mastitis. Advantages: Baby isn't hungry as often; can go longer between feedings Other people can feed the baby, leaving Mom free to do other things. You can gauge exactly how much baby eats and don't have to worry about whether he's getting enough. No dietary or medication restrictions; no sexual interference.

Kwashiokor

Caused by an unbalanced diet very low in protein Usually strikes after weaning, about 1-3 years of age Common in areas of the world in which children get enough starchy foods but too little protein. Body starts breaking down its stores of protein reserves, causing extreme abdominal swelling and listlessness.

Advantages of breast milk

Contains at least 100 ingredients not found in formula. Composition of breast milk changes throughout the day to meet baby's specific needs; also changes as baby matures More easily digested than formula; baby has less stomach upset. Has correct balance of sodium, fat, and protein to put less strain on baby's kidneys Baby absorbs calcium better with breast milk. Less risk of allergy to breast milk than to formula, although baby can be sensitive to something Mom has eaten. Constipation almost never occurs in the baby who is breastfed. Babies get essential antibodies that will bolster immune system. Get sick less often. Breastfeeding may prevent obesity in children and adults. Breast milk is free, convenient, and offers Mom some protection against breast cancer before menopause. Mothers who breastfeed must take in an extra 500 calories a day to compensate for calories lost during breastfeeding. Theoretically, breastfeeding Moms should lose weight faster, and it's always been said to be true. New research suggests that breastfeeding moms lose LESS weight initially than bottle-feeding moms do, but 8 years later, they are thinner than their bottle-feeding counterparts.

Pruning

Doesn't occur in all parts of the brain at the same time. Example: Synapses in language centers reach maximum density at around 3 years old whereas synapses in the occipital lobe (visual cortex) are maximally dense when an infant is 4 months old. A 1-year-old actually has denser dendrites and synapses than an adult does. Even at age 4, synaptic density is twice that of an adult's. Pruning occurs in spurs throughout childhood and adolescence.

Crying

First way babies communicate with parents—signals distress Usually cry because of physical needs, but they also cry when they hear other babies crying. 80-90% of babies have crying spells of up to 1 hour per day that aren't easily explained. Crying time often corresponds with dinnertime and may be related to sensory overload.

Failure to Thrive FTT

General consensus that it should be based on growth alone; weight and height remain consistently far below normal (bottom 3% of height & weight). Accounts for 3% of pediatric hospital admissions. Organic 30% of cases Problem is usually a gastrointestinal disease or sometimes a problem with the nervous system Non-organic Much more difficult to diagnose and treat Associated with poverty, neglect, poor parenting, lack of love Associated with serious caregiving deficits Parents alternate between periods of hostility, impatience, avoidance, and coldness. Often seen in orphanages

Motor development

Gross motor development Control over actions that help the infant get around the environment (crawling, standing, walking) Fine motor development Smaller movements such as reaching, grasping, and holding crayons Cephalocaudal trend occurs (motor control of head occurs before control of arms and trunk, which comes before the limbs. Proximodistal trend is also evident: control of head, trunk, and arms is more advanced than control of hands and fingers.

Smiling

Helps ensure an infant's survival by making the adult feel tenderness toward him/her. Two types of smiling—reflexive & social. Reflexive smiling—first month of life; child smiles for no apparent reason, usually during sleep (doesn't appear in alert state) Social smiling—appears somewhere around 2 months of age (some say as early as 3 weeks); baby smiles in response to a face

Problems with family bed

Increased sleep disorders in children (sleep problems found in 35-50% of co-sleepers), compared to 7-15% of those who sleep alone Dental problems—co-sleeping babies continually feed during the night, which causes cavities Developmental problems—Controversial topic; some theorists believe that child can't develop independent sense of self when co-sleeping Peer problems—school-age cosleeping child could be made fun of Marital problems—cosleeping creates difficulties for parents attempting intimacy Safety problems—the biggest issue; sharing bed greatly increases chances of child dying during night (by smothering)

Pain

Infants do experience pain. Infants who experienced severe pain as newborns (as in circumcision) showed a greater pain response to routine vaccinations later in infancy. Newborns have more resiliency in getting over painful events, however. Circumcised boys often sleep deeply after the procedure, probably as a coping mechanism.

REM Sleep

Infants spend 50% of total sleep time in REM sleep By age 3-5 years, it declines to 20%...the same amount an adult has It's thought that REM sleep is vital to baby's development—helps stimulate the CNS. REM sleep is disturbed in infants who are brain-damaged or have severe birth trauma. Poorly sleeping babies are likely to be behaviorally disorganized & have problems learning. Trouble with interactional synchrony

SIDS

Leading cause of death in US of infants between ages of 1 month and 1 year (2-3 per 1000 children die of SIDS in US every year) SIDS especially prevalent in Australia & New Zealand; low in Japan and Sweden. Reasons unknown. With SIDS, babies simply stop breathing during naps or nighttime sleep, and they die. More common in winter when babies suffer more respiratory infections More common in males than females Highest rates with babies 2-4 months of age Putting a baby to sleep on stomach is a big risk factor—PUT BABY TO SLEEP ON ITS BACK! Babies who have history of apnea—brief periods when breathing stops—are more likely to die of SIDS Racial differences: SIDS rates highest in Native Americans, then Blacks, then Whites, and finally, Asians. SIDS rates are higher among the poor and among moms who didn't get proper prenatal care. Preterm or low-birth-weight babies are at higher risk, as are those who had low APGAR scores. If women stopped smoking while pregnant, the SIDS rate would drop by 30%. Babies who are exposed to smoke either prenatally or after birth (in the home) are 4 times more likely to die of SIDS. Brains of SIDS babies often show signs of delayed maturation. Myelinization of neurons has progressed at a slower rate May be that inadequate fat intake in last month of pregnancy or during infancy may contribute to the problem (link with dietary fat) American Academy of Pediatrics issued a statement in October of 2005 advocating the use of pacifiers as a deterrent of SIDS. Pacifier use has now been added to the SIDS prevention list. Do not smoke or allow baby to be exposed to any smoke. Put baby on back to sleep. Keep room fairly cool (68-72 degrees). Don't put blankets, stuffed animals, or pillows in crib. Make sure mattress is firm. Eat well during pregnancy; don't skimp on fat.

When reflexes disappear

Most early reflexes disappear in 6 months to a year after birth. Protective reflexes (sneezing, blinking, yawning, shivering, pupillary reflex) remain. Disappearance of unneeded reflexes on schedule is a sign that motor pathways in cortex have been partially myelinated, enabling a shift to voluntary behavior. Doctors assess neurological function by seeing if reflexes disappear when they're supposed to.

Obesity

New studies are focusing on the dangers of obesity in infancy because, contrary to what was thought only a few years ago, it may predict adult obesity. Most babies thin out during toddlerhood and the preschool years as growth slows and become more active, but some remain obese. Some researchers believe that weight setpoint is set in the first year of life, though. Bottle-fed babies are 2 ½ times more likely to become obese than breastfed babies, although some studies refute this finding.

Hearing

Newborns can hear a wide range of sounds Prefer complex tones such as noises and voices instead of pure tones Biologically programmed to respond to the sounds of any language Can respond to subtle distinctions in speech sounds Especially like high-pitched, expressive voices that rise in tone and the end of phrases & sentences (baby talk) A study showed that newborns express a preference for the Cat in the Hat if they heard it in utero. (Fetus can hear by 33-34 weeks.) Newborns turn toward a familiar caregiver's voice within a few days of birth.

Sleep problems in infants

Nighttime waking is the most common problem. 20-30% have a hard time going to sleep at night and have nighttime waking problems. Infant waking at 1 year predict sleep problems at 4 years and are consistently linked to parents interacting with their babies at night (e.g., going in to comfort them when they hear them wake up). Solution—"sleep train" your child, starting around age 4 months. Let them cry it out (within reason). Known as the Ferber method.

Birth control breastfeeding?

Often women who breast-feed don't ovulate (and thus do not have a period). Some women use breastfeeding as birth control, but this is unreliable. You MAY ovulate while breastfeeding and could get pregnant without meaning to. Breast-feeding moms can take a "mini-pill," which is a specific version of birth control pills. It's progestin-only, which won't harm the baby.

Fine motor skills

Onset of reaching and grasping marks a significant achievement in infants' ability to interact with environment and reach goals. Pincer grasp is a special milestone, usually reached around the same time the infant starts crawling (around 9 months). Infant will then start to pick up everything in sight (and try to eat it).

Starting solids

Pediatricians recommend starting solids ("baby food") between ages of 4-6 months, depending on baby's weight and how easily he can swallow food. Whether you start with fruits or vegetables is a matter of debate. Start one food and wait for 2-3 days to see if baby has an allergic reaction. Also introduce cereal. Add meats last.

Sleep

Regular sleep—8 to 9 hours Irregular sleep—8-9 hours Drowsiness—varies Quiet alertness—2 to 3 hours Waking activity and crying—1 to 4 hours **Quiet alertness is the most variable and fleeting. Time spent in each state depends on temperament.

Taste and smell

Same capacities for taste and smell as adults Can discriminate Mom's smell from another woman's Will turn away from unpleasant odors. (They like vanilla & strawberry but don't like rotten eggs or fish.) By 6 days old, they prefer the smell of their mom's breast pad to a clean pad. Prefer sweet tastes (as do adults). Start to like salty taste around 4 months, which helps them accept solid food. Can learn to like food they once hated. Dislike bitter things, which is probably an adaptive since bitter-tasting substances are more likely to be poisonous.

IQ differences

Some studies cite a difference of 7 IQ points between bottle-fed and breastfed children (breastfed children having higher IQ) Whether the difference remains after controlling for confounding factors is controversial; most studies show that the difference disappears EXCEPT for preterm babies. Bottom line: the benefits are mainly for infants who are preterm or low birth weight and are thus more at risk for cognitive difficulties (Schulze & Carlisle, 2010).

5 step colic cure

Swaddle baby tightly so he can't move. Put baby on side or stomach Shush baby (make loud hushing sounds in baby's ear, preferably in rhythmic fashion) Swing baby from side to side Give baby something to suck on—finger or pacifier These tips are known as the 5 S's of the Cuddle Cure. From The Happiest Baby on the Block by Harvey Karp.

Changes in brain development

Synaptogenesis—the creation of synapses (connections between neurons) happens rapidly in the cortex in the first two years. Creation of synapses is responsible for the nearly tripling of brain weight during first two years. Brain development is not smooth and continuous. An initial burst of synapse formation during the 1st year is followed by a pruning of synapses in each area of the brain as redundant pathways and connections are eliminated and the wiring is made more efficient.

Plasticity

The ability of the brain to reorganize itself and "heal itself; the ability of the brain to change with experience, both good and bad. Because young children have denser dendrites and synapses than an adult has, they have greater plasticity and can recover more from a brain injury than an adult can. Flip side of plasticity: the child is especially vulnerable in the 1st 3 years of life. "Use it or lose it." Needs sufficient stimulation and good nutrition for maximal brain development.

Early human reflexes

There are 27 major innate reflexes Controlled by brain stem Play an important part in stimulating early development of CNS and muscles Primitive reflexes—e.g., sucking, rooting for nipple, Moro reflex, grasping—related to need for survival and protection Postural reflexes—reactions to changes in position/balance—e.g., parachute reflex

Myelination

This is the process of creating the myelin sheath around axons (a fatty protein coating called myelin that covers the tail of the neuron). Helps transmit messages more efficiently from the brain to other parts of the body. Myelination is dependent on dietary fat and is most rapid in the first two years after birth but continues at a slower pace throughout childhood & adolescence. Follows a cephalocaudal, proximodistal pattern. (Babies get control of their hands before their feet, hands before fingers, etc.)

Sucking reflex

Two purposes—babies get nourishment, and they get enjoyment out of sucking Even fetuses show sucking reflex Non-nutritive sucking—85% of babies do it (suck on pacifier, fist, etc.) As many as 40% of children suck their thumbs after they've started school. Sucking behavior is also used to gauge a baby's attention or interest in people, things, or noises.