What Are the Possible Side Effects of Phototherapy in Newborns?

Phototherapy is a common treatment for newborn jaundice, where high bilirubin levels cause yellowing of the skin and eyes. Using specific wavelengths of light, phototherapy breaks down excess bilirubin for excretion. While generally safe and effective, it has potential side effects that caregivers should monitor.

Skin-Related Effects

Phototherapy can cause temporary skin redness, or transient erythema, due to increased blood flow to the skin’s surface. This effect, more common in fair or sensitive skin, typically resolves after treatment but may cause irritation in preterm infants with underdeveloped skin barriers.

Dryness and peeling are also frequent, resulting from increased water loss under phototherapy lamps. The heat accelerates moisture evaporation, leading to flaking. Maintaining appropriate humidity levels can help mitigate this effect.

A distinct condition, “bronze baby syndrome,” occurs in some infants with elevated direct bilirubin levels, leading to grayish-brown skin discoloration. Though harmless and temporary, it can be concerning for parents.

In rare cases, extremely preterm infants may develop increased skin fragility, making them more prone to epidermal stripping, especially when medical adhesives are used. Gentle handling and hydrocolloid dressings can help minimize trauma.

Eye-Related Effects

Prolonged exposure to intense light poses risks to a newborn’s developing eyes, necessitating protective eye shields. These shields, typically made from hypoallergenic materials, prevent excessive exposure. However, improper positioning can lead to unintended light exposure, raising concerns about retinal damage. Some studies suggest prolonged unshielded exposure may contribute to oxidative stress in retinal cells, though long-term effects remain unclear.

Phototherapy can also cause temporary changes in pupillary response, with some infants exhibiting reduced constriction due to continuous bright light exposure. This effect resolves after treatment but highlights the importance of proper shielding. Excessive light exposure may also induce transient blepharospasm, where eyelids involuntarily contract, causing discomfort and increased tear production.

Research has explored phototherapy’s influence on early visual development. A systematic review in Pediatrics examined its effects on visual tracking and contrast sensitivity. While no definitive long-term impairments were found, some studies noted subtle differences in light adaptation and contrast perception, suggesting follow-up evaluations may be beneficial, particularly in preterm infants.

Temperature Fluctuations

Newborns under phototherapy may experience difficulty regulating body temperature. The heat from phototherapy units can cause mild hyperthermia, increasing metabolic demands and fluid loss. While modern devices include cooling mechanisms, monitoring is necessary to prevent excessive warmth.

Conversely, some infants may develop hypothermia, particularly in open bassinets where clothing is removed for maximum light exposure. This risk is higher in low-birth-weight infants with minimal fat reserves. Maintaining an ambient temperature of 26-28°C (78-82°F) and using temperature-controlled incubators can help stabilize body temperature.

Electrolyte Variation

Phototherapy can affect electrolyte balance, primarily through increased water loss, leading to dehydration if fluid intake is not adjusted. This can result in hypernatremia, or elevated blood sodium levels, particularly in preterm infants whose kidneys struggle to conserve electrolytes.

Calcium levels may also be affected, with some studies linking phototherapy to transient hypocalcemia. This may be due to melatonin suppression, which influences parathyroid hormone secretion. Lower calcium levels can cause neuromuscular irritability, manifesting as jitteriness or, in severe cases, tetanic spasms. While usually short-lived, monitoring calcium levels may be necessary for at-risk infants.

Behavioral And Sleep Issues

Phototherapy can disrupt newborn sleep patterns. While newborns lack fully developed circadian rhythms, continuous bright light exposure can reduce sleep duration and increase wakefulness, causing irritability. Intermittent phototherapy or adjusting light intensity may help minimize disruptions while ensuring bilirubin levels decrease effectively.

Feeding behavior and activity levels may also change, with some infants appearing fussier or less efficient at feeding, possibly due to mild discomfort from temperature fluctuations or dehydration. Others may seem more lethargic following extended exposure, likely due to metabolic shifts as bilirubin breaks down. Encouraging frequent feedings and skin-to-skin contact can help stabilize behavior and provide comfort.

Potential Oncological Associations

Some studies have explored a potential link between neonatal phototherapy and an increased risk of childhood cancers, particularly acute myeloid leukemia (AML). While a few retrospective analyses suggest a slight association, no definitive causal relationship has been established. Other factors, such as preexisting conditions leading to jaundice or genetic predispositions, may contribute to observed correlations.

Laboratory studies examining cellular effects of blue light exposure have not demonstrated significant DNA damage beyond normal metabolic processes. Large-scale registry-based studies indicate no notable increase in pediatric cancer incidence despite widespread phototherapy use. Medical guidelines continue to endorse phototherapy as a safe and necessary treatment, with ongoing research monitoring long-term health outcomes.