Physiologic and Behavioral Adaptations of the Newborn

These vocabulary flashcards cover the physiological and behavioral adaptations of the newborn, including thermoregulation, fetal circulation transitions, hematologic changes, and gastrointestinal and hepatic functions as presented by Dr. Wendy Gibbons.

Transition to Extrauterine Life

The period generally occurring in the first 6-8 hours of life where major adaptations involve heart rate, respirations, temperature, and gastrointestinal function mediated by the sympathetic nervous system.

Evaporative Heat Loss Prevention

The process of drying and stimulating the newborn on the maternal chest and placing a hat on the head to maintain warmth immediately following birth.

Brown Fat

The specialized tissue newborns use to create heat because they have a very limited ability to maintain body temperature and do not shiver.

Convection

Heat loss from the newborn's body to cooler ambient air currents, such as fans, vents, windows, or drafts.

Radiation

The loss of heat from the body surface to cooler solid surfaces not in direct contact but in relative proximity.

Evaporation

The loss of heat that occurs when liquid is converted to vapor, such as during sweating, being wet, or during a bath.

Conduction

The loss of heat from the body surface to cooler surfaces in direct contact, such as cold blankets or exam surfaces.

Hypothermia Consequences

A condition that leads to increased $O_2$ consumption, pulmonary vasoconstriction, decreased $PO_2$ and $pH$, and metabolic acidosis.

Hyperthermia

An elevation in body temperature often caused by sepsis, maternal fever, or inappropriate use of external heat sources, which can lead to neurologic injury and seizures.

Ductus Venosus

A fetal shunt that allows oxygen-rich blood from the umbilical vein to bypass the liver and flow directly into the inferior vena cava.

Foramen Ovale

An opening between the right and left atrium that allows oxygen-rich blood to shunt from right to left due to higher pressure in the right atrium in-utero.

Ductus Arteriosus

A shunt between the pulmonary arteries and the aorta that allows oxygen-rich blood to bypass the inactive lungs; it functionally closes within 24 hours as $PO_2$ rises.

Normal Newborn Heart Rate

$$120-160 \text{ beats/min}$$

Delayed Cord Clamping (DCC)

A procedure that expands blood volume and reduces the risk for Intraventricular Hemorrhage (IVH) and Necrotizing Enterocolitis (NEC).

Fetal $PO_2$

$$20-30 \text{ mm Hg}$$

Leukocytosis in Newborns

A normal finding at birth where the white blood cell (WBC) count can be as high as $30,000/mm^3$.

Uric Acid Crystals

A normal occurrence in the transitional period that gives a pink-tinged or "brick dust" appearance in the newborn's diaper.

Gastroesophageal Reflux (GER)

The involuntary backflow of stomach contents into the esophagus causing newborns to spit up and vomit frequently during the first 3 months.

Newborn Stomach Capacity

Varies by age: $<10 \text{ mL}$ on day 1, $30 \text{ mL}$ on day 3, and $60 \text{ mL}$ on day 7.

Hepatic Iron Store

The liver provides approximately a 4-month store of iron at term, though preterm infants may deplete these stores sooner.

Glucose Homeostasis

The stabilization of glucose levels by 2-3 days of life following an initial drop in the first 30-90 minutes which triggers increased glucagon and decreased insulin.

Vitamin K Administration

Required to activate coagulation factors synthesized in the liver and prevent Vitamin K deficiency bleeding since the newborn lacks intestinal bacteria.

IgG Antibodies

The primary circulating antibodies in the newborn, which are acquired from the mother to help compensate for a reduced immune response.

State Regulation

A behavioral adaptation involving the ability to modulate the state of consciousness, develop predictable sleep/awake states, and react to stress.