7 Newborn Transition and Assessment

Transition after birth

Birth requires rapid changes in breathing, circulation, and temperature regulation. Before birth, the placenta supplies oxygen, and the fluid-filled lungs receive little blood flow. With the first breaths, the lungs expand and clear fluid; surfactant helps keep the air sacs open. Rising oxygen levels and falling pulmonary vascular resistance increase blood flow through the lungs.

Blood returning to the heart from the lungs helps functionally close the foramen ovale. The ductus arteriosus constricts over the following hours to days. Because these changes are gradual, newborns need observation for effective breathing and circulation.

Newborns lose heat easily and have limited ability to regulate temperature. Drying, a warm environment, and skin-to-skin contact help prevent heat loss, while cold stress increases energy and oxygen demands. A vigorous infant who is breathing effectively can usually remain skin-to-skin with the parent as routine care begins. If breathing or heart rate is inadequate, prompt assessment and resuscitation take priority.

Apgar assessment

The Apgar score describes five features: heart rate, respiratory effort, muscle tone, reflex response, and color. It is recorded at one and five minutes to communicate the newborn’s condition and response to support. It does not determine whether initial resuscitation should begin and does not predict an individual child’s long-term outcome.

Systematic newborn assessment

Begin by reviewing pregnancy, labor, and birth history. Relevant details include gestational age; maternal conditions and medications; infection risks; duration of rupture of membranes; amniotic fluid; delivery events; and whether resuscitation was needed. Measure weight, length, and head circumference, then plot the measurements against standards appropriate for gestational age and sex.

A complete clinical examination is generally performed within the first 24 hours. Assess earlier or repeat the examination when the newborn’s condition or risk factors require it. Examine the infant when calm and warm, using a consistent head-to-toe sequence.

General appearance and vital signs

Assess alertness, tone, posture, color, activity, temperature, heart rate, and respiratory rate. Typical resting heart rate is approximately $100\text{–}160$ beats per minute, and typical resting respiratory rate is approximately $30\text{–}60$ breaths per minute. Interpret these values in context and repeat them when the infant is settled. Observe breathing rather than relying only on a brief count.

Head-to-toe findings

• Skin: Assess color, perfusion, bruising, birthmarks, rashes, jaundice, and signs of trauma. Acrocyanosis, or bluish hands and feet, can occur early. Blue lips or tongue indicate central cyanosis and are concerning.

• Head and face: Assess molding, sutures, fontanelles, symmetry, facial features, eyes and red reflex, ears, nose, and mouth. Check the palate and suck. Distinguish common scalp swelling from findings that may indicate bleeding or injury.

• Chest and heart: Assess chest symmetry and work of breathing, air entry on both sides, heart rate and rhythm, heart sounds, and murmurs. Palpate brachial and femoral pulses and assess perfusion.

• Abdomen and cord: Assess abdominal contour and softness, check for masses, and inspect the cord vessels, which normally comprise two arteries and one vein. Check for bleeding or abnormal drainage.

• Genitalia and elimination: Inspect the genitalia and confirm that the anus appears patent. Ask about and document urine and stool passage; investigate abnormal findings or delayed passage according to clinical protocol.

• Musculoskeletal and neurologic systems: Inspect the spine and limbs, palpate the clavicles, assess movement and symmetry, and evaluate hip stability using trained techniques. Observe tone and elicit age-appropriate primitive reflexes, such as rooting, sucking, grasp, and Moro.

A reassuring initial examination does not rule out conditions that develop or become apparent later.

Gestational age and growth

Use the best obstetric estimate of gestational age, especially early ultrasound and pregnancy dating, as the primary estimate. If dating is uncertain or the newborn’s apparent maturity is inconsistent with the history, a trained clinician may use the New Ballard Score. It combines six neuromuscular signs, including posture, arm recoil, and popliteal angle, with six physical signs, including skin, lanugo, plantar creases, breast tissue, eyes and ears, and genital development. Greater neuromuscular tone and physical maturity generally correspond to greater gestational age.

Classify gestational age as follows:

• Preterm: before $37$ completed weeks.

• Term: from $37$ weeks through $41$ weeks and $6$ days.

• Postterm: $42$ weeks or more.

Classify size separately using an appropriate growth chart. Small for gestational age means below the $10$th percentile; appropriate for gestational age means from the $10$th through the $90$th percentile; and large for gestational age means above the $90$th percentile. Gestational age and size together help identify newborns who may need additional observation, such as observation for temperature or glucose problems.

Routine care and prevention

For a stable newborn, essential care includes thorough drying, warmth, skin-to-skin contact, assessment of breathing, support for early feeding, infection prevention, and ongoing assessment for health problems. Delayed cord clamping is recommended in many routine situations when clinically appropriate; follow current local guidance and consider the newborn’s condition.

Support breastfeeding or the family’s chosen feeding plan. Assess latch, feeding cues, and intake. Maintain a warm environment and delay bathing until the infant is stable and warm. Keep the cord clean and dry and follow local infection-prevention practice. Give intramuscular vitamin K to prevent vitamin K deficiency bleeding, following the applicable newborn protocol.

Provide ocular infection prophylaxis and immunizations according to local law and current guidance, taking maternal infection results and infant-specific circumstances into account. Verify identity and security procedures, document findings and interventions, and arrange timely follow-up. Teach caregivers safe sleep practices: the infant should sleep alone, on the back, and on a firm, flat sleep surface. Also provide feeding guidance and explain warning signs that require urgent care.

Screening and signs requiring escalation

Complete newborn screening required in the jurisdiction. Screening commonly includes a blood-spot test for selected disorders, a hearing screen, and pulse-oximetry screening for critical congenital heart disease before discharge. Screening can identify concerns that are not apparent on physical examination, but a screen is not a diagnosis.

Escalate promptly for apnea, grunting, persistent retractions or tachypnea, central cyanosis, poor perfusion, temperature instability, markedly abnormal tone or responsiveness, weak feeding, bilious vomiting, or other signs of illness. Continue observation and arrange follow-up because some conditions may not be apparent during the initial examination.

• Newborn transition