Birth and Newborn Transition

Gestational Age (GA)

Measured from the 1st day of the Last Menstrual Period (LMP) to the date of delivery; used to classify infants as preterm, term, or post term.

Preterm

Birth before 37 weeks gestation.

Term

Birth between 37 weeks 0 days and 41 weeks 6 days gestation.

Post term

Birth at 42 weeks 0 days gestation or more.

Neonate

An infant less than 4 weeks (28 days) old.

Breathing at birth

Air exposure and temperature change stimulate the infant to take a first breath (avg. ~10 seconds); increased oxygen in the lungs decreases pulmonary blood flow resistance while the infant's own blood vessel resistance increases; fluid drains from the respiratory system so the lungs inflate and begin gas exchange.

Circulatory transition at birth

With the first breath and pressure change, the foramen ovale (FO) and ductus arteriosus (DA) close, and circulation shifts to go through the lungs.

Body temperature at birth

A dramatic drop in temperature is sensed by skin receptors, promoting burning of brown fat for warmth.

GI/Genitourinary transition

Undergoes a significant period of adjustment at birth.

Neonatal period

Birth to 1 month of age; period of adjustment to life outside the womb involving recovery from birth and fine-tuning of vital functions (orientation, habituation, motor maturity, self-quieting ability, social behaviors).

Orientation (newborn behavior)

Movement of head and eyes in response to auditory and visual stimuli; learning is observable from birth; newborns prefer human faces and bright, shiny objects.

Habituation

The newborn's ability to learn/recognize and become accustomed to repeated stimuli, and to block out external stimuli once accustomed.

Motor maturity (newborn)

Smoother, more organized movements with improving quality of muscle tone and activity level.

Self-quieting/soothing

Capacity to habituate to external light and sound and to self-regulate, including crying and the ability to console.

Social behaviors (newborn)

Visual, auditory, and social-interactive capacities reflecting degree of alertness and response to human and nonhuman stimuli.

Kangaroo Care

Skin-to-skin holding of a LBW/preterm infant by a parent/caregiver, mostly upright, up to 2-3 hours/day; infant is naked except for a diaper with back covered by a blanket.

Kangaroo Care benefits (baby)

Stable heart rate, more regular breathing (~75% decrease in apneic episodes), improved O2 saturation, better temperature regulation, longer sleep, more rapid weight gain and brain development, decreased crying, longer alertness, more successful breastfeeding, earlier hospital discharge.

Kangaroo Care benefits (parent)

Builds confidence in caring for the baby, reduces stress, promotes bonding.

AAP pain statement (2016)

Prevention of pain in neonates should be a goal for all pediatric providers, both because it is ethical and because repeated painful exposures can have deleterious consequences.

Challenges assessing infant pain

Infants cannot describe pain; behavioral repertoire is limited; no single behavior can be attributed with certainty to pain.

Pain Assessment Tool (PAT)

Assesses respirations, heart rate, oxygen saturation, and blood pressure.

Premature Infant Pain Profile (PIPP)

Assesses heart rate and oxygen saturation.

CRIES tool

Cry, Requires oxygen, Increased vital signs, Expression, Sleeplessness.

Neonatal Infant Pain Scale (NIPS)

Assesses respiratory patterns, changes in vital signs, and body movements.

Signs of stress/pain in newborns

Sudden high-pitched cry, body posturing (squirming, kicking, arching), increased HR/BP/pulse/respirations, facial grimace with furrowed brow and quivering chin, increased muscle tone, oxygen desaturation, limb withdrawal/thrashing.

Nonpharmacologic pain management

Gentle handling, rocking, caressing, cuddling, massaging; rest before/after painful procedures; kangaroo care during procedures; breastfeeding for minor procedures.

Facilitated tuck

Holding an infant's arms and legs in a flexed position to reduce pain/stress.

Swaddling (pain management)

Wrapping/positioning the infant to establish physical boundaries and promote calming.

Nonnutritive sucking

Sucking on a pacifier, often dipped in sucrose, prior to a procedure to reduce pain response.

Environmental pain-reduction techniques

Warm blankets, reducing environmental noise/light (alarms, beepers, conversations), distraction with colored objects/mobiles, placing twins in the same isolette.

Sucrose (pain management)

Reduces procedural pain (heel prick, venipuncture) more effectively than topical anesthetic creams; effective dose peaks ~2 minutes after administration and lasts several minutes; mechanism not fully defined; no adverse effects with a single dose.

Opioid analgesia (neonates)

Used for severe/prolonged pain; has sedative properties; undesirable effects include hypotension, decreased gut motility, increased ventilation duration, and withdrawal signs even after short treatment.

Self-calming behaviors in the neonate

Hand-to-face/hand-to-mouth, sucking on hands/fingers/thumb/pacifier, maintaining flexed posture, hands or feet in midline, gaze aversion.

Neonate classification methods

By birthweight, by gestational age, or by gestational age and birthweight combined (AAP recommends classifying by both GA and birthweight).

Low Birth Weight (LBW)

Birthweight less than 2500 g (5 lb 8 oz).

Very Low Birthweight (VLBW)

Birthweight less than 1500 g; can occur in preterm, full-term, or post-mature infants.

Common causes of LBW

Preterm birth (before 37 weeks) and intrauterine growth restriction.

LBW risk factors

Preterm labor (any GA), maternal chronic health conditions (cardiovascular disease, high blood pressure), maternal infections, maternal substance use, environmental toxins (air pollution, lead), inadequate maternal weight gain during pregnancy.

LBW/prematurity statistics

About 10% of US babies are born preterm; about 8% are born LBW; LBW and prematurity are the 2nd leading cause of infant mortality in the US; global infant mortality rate for LBW infants is ~20x that of normal birthweight infants.

LBW immediate complications

Temperature regulation difficulties and nutrition/feeding issues; risk increases as birthweight decreases.

LBW long-term risks

Certain health conditions, developmental delays, mental health issues.

Small for Gestational Age (SGA)

Birthweight below the 10th percentile for gestational age; risk factors include multiples, placental abruption, preeclampsia, maternal smoking/alcohol/drug use, or other chronic conditions; SGA infants generally do not have the organ-immaturity complications seen in preterm infants of similar size.

Average for Gestational Age (AGA)

Birthweight between the 10th and 90th percentile for gestational age.

Large for Gestational Age (LGA)

Birthweight above the 90th percentile for gestational age; primary risk factor is maternal diabetes.

Macrosomia

Birthweight greater than 4000 g (8.8 lb).

LGA complications

Shoulder dystocia, clavicle or limb fracture, brachial plexus injury, respiratory distress, meconium aspiration, hypoglycemia.

Preterm birth risk factors

Previous preterm birth, maternal age younger than 16 or older than 35, delayed/absent prenatal care, maternal smoking or drug use, chronic health conditions, infections, preeclampsia or placental abruption.

Preterm immediate complications

Underdeveloped organs (lungs, eyes, brain), need for surfactant, retinopathy of prematurity, increased risk of intracranial/intraventricular hemorrhage (IVH), NICU stay, nutrition/feeding issues, temperature regulation problems, ventilator support, surfactant replacement therapy.

Retinopathy of Prematurity

Abnormal blood vessel development in the retina associated with prematurity.

Intraventricular Hemorrhage (IVH)

Bleeding inside or around the ventricles of the brain; preterm infants are at increased risk.

Preterm long-term outcomes

Increased risk of developmental delays (cognitive, social-emotional, behavioral, motor); approximately 40% of children with cerebral palsy (CP) were born preterm; increased risk of chronic respiratory disease, cardiovascular disorders, hearing issues, and vision problems.

Effects of prematurity on body systems

Physiological flexion, temperature regulation, hyperbilirubinemia.

Physiological Flexion

The normal flexed posture typically seen in term newborns; often underdeveloped or absent in preterm infants due to decreased muscle tone.

Body temperature regulation risk factors (preterm)

Increased susceptibility to hypothermia due to inadequate subcutaneous fat insulation, lack of muscle tone/flexion to conserve heat, limited muscle mass/activity, inability to shiver, and an immature temperature-regulating center in the brain.

Thermoregulation

Maintaining the balance between heat loss and heat production; neonates depend on their environment to maintain body temperature and are vulnerable to both underheating and overheating.

Neutral Thermal Environment

A condition in which body temperature is maintained without an increase in metabolic rate or oxygen use, promoting growth/stability and conserving energy for basic bodily functions.

Physiological Jaundice

Yellow coloration of the skin, whites of the eyes, and mucous membranes caused by hyperbilirubinemia; about 50% of infants show signs in the first week of life; preterm or SGA infants may be at greater risk and require intervention at lower bilirubin levels.

Bilirubin

A breakdown product of red blood cells (RBCs).

Hyperbilirubinemia

Increased levels of bilirubin in the blood.

Jaundice

Yellow coloration of the skin and eyes due to hyperbilirubinemia.

Kernicterus

Bilirubin-induced neurologic damage; permanent brain damage from bilirubin toxicity.

Signs of Acute Bilirubin Encephalopathy

Listlessness, difficulty waking the baby, high-pitched crying, poor sucking/feeding, backward arching of the neck and body, fever.

Signs of Kernicterus (permanent damage)

Involuntary/uncontrolled movements, permanent upward gaze, hearing loss.

Causes of jaundice

Preterm birth, difficulty with breastfeeding, and normal liver immaturity, common even in healthy term neonates as the liver continues to develop.

Interventions for jaundice

Keep the baby well hydrated and increase feedings; promote elimination since early feedings reduce bilirubin reabsorption by stimulating intestinal activity; phototherapy.

Post term infant

Born at 42 weeks or more of gestation; accounts for approximately 5% of births; cause often unknown, but risk factors include previous post term delivery and miscalculation of due date.

Post term complications

After 42 weeks the placenta loses ability to nourish the fetus, affecting oxygen diffusion; leads to tissue wasting/undernourishment, dry peeling skin, decreased amniotic fluid, meconium aspiration, fetal distress/perinatal asphyxia, and increased risk of hypoglycemia.

Meconium Aspiration

Infant breathes in a mixture of amniotic fluid and meconium (the infant's first stool).

Perinatal Asphyxia

Lack of blood flow or oxygen to the brain around the time of birth.

Prevention of post term birth

Accurate pregnancy due dating; early ultrasound to establish accurate gestational dating via fetal measurements; ultrasound also used to evaluate the placenta for signs of aging.

Purpose of GA/BW assessment

Allows the healthcare team to plot growth parameters and anticipate potential risks related to prematurity, postmaturity, and growth abnormalities.

PT role with newborns

Understand and recognize common problems associated with the newborn and monitor at-risk newborns for signs/symptoms of distress requiring follow-up.