week 1: the normal newborn

Vocabulary flashcards covering the key concepts from the lecture notes on the normal newborn, including physiologic and behavioral adaptations, thermoregulation, respiratory and cardiovascular changes, hematologic and immune development, feeding and nutrition, jaundice, reflexes, and neonatal care practices.

Neonate

A newborn infant from birth to day 28 of life.

Transition to extrauterine life

• The physiologic and behavioral adjustments a newborn makes to life outside the womb

  • respiration

  • circulation

  • temperature

  • ingesting, retaining, and digesting nutrients

  • waste elimination

  • weight regulation

Respiratory adaptation

• Physiologic changes enabling breathing at birth

  • chemical

  • mechanical

  • thermal

  • sensory factors

chemical factors in initiation in breathing

• decreased P02

• increases PC02

• decreased Ph

  • occurs during last moments of labor

mechanical factors in initiation of breathing

• compression of chest with birth

  • negative intrathoracic presssure helps draw air into lungs

thermal factors factors in initiation of breathing

decreased temp in extra-uterine environment

sensory factors in initiation of breathing

• drying

• suctioning

• environmental factors

  • cold air

  • noises

  • touching

Initiation of breathing

Triggering of the first breath due to chemical, mechanical, thermal, and sensory stimuli; signs include tachypnea, nasal flaring, cyanosis, expiratory grunting, and intercostal retractions.

Tachypnea

Abnormally rapid breathing; a sign of respiratory distress in the newborn.

Nasal flaring

Widening of the nostrils during breathing, often a sign of distress.

Acrocyanosis

Bluish coloration of the hands and feet that is normal for the first 24–48 hours.

Periodic breathing

Breathing pauses lasting about 5–15 seconds common in newborns.

Obligate nasal breather

Newborns primarily breathe through the nose and may not breathe well through the mouth.

Ductus Venosus

A fetal vessel that bypasses the liver by channeling blood from the umbilical vein to the inferior vena cava.

Foramen ovale

A hole in the heart that allows most blood in the right atrium to pass to the left atrium, bypassing pulmonary circulation.

Ductus Arteriosus

• A vessel connecting the pulmonary artery to the aorta that bypasses the lungs

• normally constricts and closes after birth

Transient murmurs

• temporary heart murmurs

• result from normal transitional circulatory changes

Heart rate range (neonate)

Normal resting heart rate is about 120–160 beats per minute.

PMI (Point of Maximal Impulse)

• Location of the strongest heartbeat

• typically at the 4th intercostal space, left of the midclavicular line.

Neonate heart sounds

• S1 is typically louder/duller

• S2 is sharper.

Hematopoietic system

Blood cell system in the newborn, including red cells, white cells, and platelets.

Hemoglobin at birth (Hgb)

Normal range of about 14–24 g/dL at birth.

WBC range in newborns

White blood cells typically range from about 9,000 to 30,000/µL, stable around 12,000/µL.

Vitamin K

• not naturally made by our bodies

• coagulation factors are activated by this

• absent in babies due to sterile intestinal tract ( no normal intestinal flora)

• 0.5–1 mg given intramuscularly within 1 hour of birth (AquaMEPHYTON) to prevent bleeding.

Thermogenic system

Body heat production and loss regulation in the newborn.

causes of heat loss in neonates

• large body surface compared to mass

• thin epidermis/ vessels close to skin

• less insulating fat

  • especially for preterm babies

*why babies should be wrapped up as much as possible

thermogenesis in neonates

• hypothermia and cold stress

• hyperthermia

mechanisms neonates use to increase heat production

• increased basal metabolism

• muscular activity

• non shivering thermogenesis (babies can’t shiver when cold)

Brown fat

• Special adipose tissue used for nonshivering thermogenesis

• primary heat source when cold

• 2-6% of body’s weight

Heat loss methods

Radiation, convection, evaporation, and conduction.

Radiation

Loss of heat from the body to a cooler surface not in direct contact.

Convection

Heat loss to cooler ambient air surrounding the body.

Evaporation

Heat loss due to moisture evaporating from the skin.

Conduction

Heat loss to a cooler surface via direct skin contact.

Nonshivering thermogenesis

Heat production mainly via brown fat metabolism without shivering.

Meconium

The newborn’s first stool: thick, black, tarry.

Stool types

Meconium, transitional stool (green/brown), breastfed stool (yellow, more liquid).

Feeding energy need

Approximately 110 kcal/kg/day in the first few months.

Foremilk

The initial, lower-fat milk at the start of a feeding.

Hindmilk

The later milk during a feeding that is higher in fat.

Let-down reflex

Milk ejection triggered by oxytocin in response to sucking.

Lactogenesis I–III

Stages of milk production: I (colostrum), II (transitional milk), III (mature milk).

Colostrum

Thick, creamy yellow first milk rich in protein and antibodies (Lactogenesis I).

Transitional milk

Milk produced after colostrum, increasing volume (Lactogenesis II).

Mature milk

Milk present by about 2 weeks; thin, white, with high water content and balanced nutrients (Lactogenesis III).

Latch

Attachment of infant to breast; determines effectiveness of breastfeeding.

Let-down signs

Audible or palpable milk ejection during feeding.

Sucking reflexes

Reflexes including rooting and sucking that aid feeding.

Rooting reflex

Turning the head toward a touch on the cheek to find the nipple.

Palmar grasp reflex

Infant reflex where fingers grasp when the palm is touched.

Plantar grasp reflex

Toes curl downward when the sole is touched.

Moro reflex

Startle response with arm extension and then embrace; protective reflex.

Stepping reflex

Baby makes stepping motions when held upright with feet touching a surface.

Trunk incurvation (Galant) reflex

Side-to-side flexion of the trunk in response to stroking along the spine.

Fontanels

Soft spots on a newborn’s skull; should be soft and flat.

Bulging fontanel

Possible sign of elevated intracranial pressure or vigorous crying.

Sunken fontanel

Late sign of dehydration.

Caput succedaneum

Edematous swelling of the scalp crossing suture lines; resolves in ~3 days.

Cephalhematoma

Collection of blood between skull bone and periosteum; does not cross sutures; may take weeks to resolve and can raise bilirubin.

Subgaleal hemorrhage

Bleeding beneath galea layer; can cross sutures and be life-threatening.

Molding

Overlapping of skull bones during birth; usually resolves within 24–48 hours.

Fontanels and sutures

Fontanels should be soft/flat; sutures may be overlapped due to molding.

Caput vs cephal hematoma

Caput is diffuse scalp edema; cephalhematoma is a localized bleed under the skull bone.

Newborn reflexes list

Palmar, plantar, Babinski, Moro, stepping, trunk incurvation, rooting, sucking.

Sleep-wake states

Behavioral patterns influenced by gestational age, time, stimuli, and meds.

Jaundice (bilirubin)

Hyperbilirubinemia; excess bilirubin due to various causes, including immaturity and increased RBC turnover.

Physiologic jaundice

Normal bilirubin rise peaking around days 3–5 (term) or 5–7 (preterm); usually self-limiting.

Pathologic jaundice

Jaundice appearing within 24 hours or bilirubin level above 95th percentile on nomogram.

Breastfeeding jaundice

Jaundice related to feeding inadequacy in the first week; resolves with improved feeding.

Breast milk jaundice

Late-onset bilirubin rise (5–10 days) related to milk composition; can last weeks.

Transcutaneous bilirubinometer (TcB)

Noninvasive device to estimate bilirubin levels on the skin.

Total serum bilirubin (TSB)

Blood test measuring bilirubin level to assess jaundice severity.

Phototherapy

Treatment using light to convert bilirubin into water-soluble forms for excretion.

Exchange transfusion

Blood transfusion to rapidly reduce bilirubin levels in severe cases.

Immunologic adaptation

Not fully activated at birth; IgM produced by fetus, IgG crosses placenta, IgA develops after ~4 weeks.

IgM

Immunoglobulin produced by fetus beginning at ~8 weeks gestation; does not cross placenta.

IgG

Immunoglobulin that crosses the placenta providing passive immunity.

IgA

Immunoglobulin produced by newborns starting around 4 weeks; initially acquired postnatally.

Integumentary features

Skin structures and features such as sweat glands, desquamation, Mongolian spots, erythema toxicum.

Kangaroo care

Skin-to-skin contact between newborn and parent; improves thermoregulation, breathing, glucose, breastfeeding, and bonding.

Gastrointestinal basics

Newborn capable of swallowing, digesting, absorbing simple nutrients; receives meconium at first stool; breastfed stools are yellow.

Hepatic system (jaundice risk)

Liver immaturity and high RBC turnover increase bilirubin; enterohepatic circulation can elevate unconjugated bilirubin.