History of Phototherapy

The discovery of phototherapy for treating newborn jaundice was a remarkable accident. In 1958, a British nurse named Sister Jean Ward noticed that babies placed near windows had less jaundice than those kept away from sunlight. This observation led Dr. Richard Cremer and his colleagues to investigate the effect of light on bilirubin levels. Their groundbreaking research demonstrated that exposing jaundiced infants to blue light effectively reduced bilirubin concentrations in the blood.

Following this discovery, phototherapy was introduced as a standard treatment in the 1960s and quickly became the primary method for treating neonatal jaundice worldwide. Over the decades, the technology has evolved from simple fluorescent tubes to sophisticated LED systems, making treatment more effective and safer. Today, phototherapy has dramatically reduced the need for exchange blood transfusions and prevented countless cases of brain damage from severe jaundice, saving millions of lives globally.

What is a Phototherapy Unit

A phototherapy unit is a medical device that uses specific wavelengths of light to treat newborn jaundice. Jaundice occurs when bilirubin, a yellow pigment produced during the breakdown of red blood cells, builds up in the blood faster than a baby's immature liver can process it. This causes the yellowing of skin and eyes seen in approximately 60% of full-term and 80% of premature newborns during their first week of life.

The phototherapy unit emits blue-green light in the wavelength range of 460-490 nanometers. When this light penetrates the baby's skin, it converts bilirubin molecules into water-soluble forms that can be easily excreted through urine and stool without needing to be processed by the liver. This process is safe, non-invasive, and highly effective in lowering dangerous bilirubin levels.

Purpose and Where They Are Used

Phototherapy units serve the critical purpose of preventing brain damage from high bilirubin levels, a condition called kernicterus. The primary uses include:

• Treating neonatal jaundice: The most common use, addressing elevated bilirubin in term and preterm infants
• Preventing exchange transfusion: By effectively lowering bilirubin, phototherapy helps avoid the need for more invasive blood transfusions
• Managing hemolytic conditions: Used in babies with blood group incompatibilities or other conditions causing rapid red blood cell breakdown

Types of Phototherapy Units

Several types of phototherapy devices are available, each with distinct features suitable for different clinical situations:

These traditional units use fluorescent tubes or halogen bulbs mounted above the baby. They deliver standard intensity phototherapy and are widely used in hospitals. The baby lies in a crib or incubator underneath the lights, requiring eye protection.

Modern LED-based units are the most advanced option. They use light-emitting diodes that emit light specifically in the blue spectrum (450-470 nm) without producing excess heat. LED systems are more energy-efficient, have longer bulb life (up to 50,000 hours), and provide more effective treatment than conventional units.

These systems deliver light through flexible fiber optic cables to a pad or blanket placed under or wrapped around the baby. The device allows the baby to be held or fed during treatment and does not require eye protection. However, fiber optic systems are generally less effective than overhead lights for severe jaundice.

For intensive treatment, overhead lights are combined with fiber optic pads placed under the baby. This approach maximizes skin exposure and light intensity, providing the most effective treatment for severe hyperbilirubinemia.

Type	Light Source	Intensity	Best For
Conventional	Fluorescent/Halogen	Standard	Mild to moderate jaundice
LED	Light-Emitting Diodes	High	All levels, most efficient
Fiber Optic	Halogen through fibers	Lower	Home treatment, mild cases
Double/Intensive	Combination	Very High	Severe hyperbilirubinemia

User Guide: How to Use a Phototherapy Unit

• Before Starting: Verify the unit is functioning properly, check the bulb hours if applicable, and ensure the distance settings are appropriate for the type of light source being used.
• Baby Positioning: Place the baby naked except for a small diaper in a bassinet under the lights. For fiber optic systems, position the pad under the baby's back.
• Eye Protection: Apply opaque eye shields for overhead lights to prevent potential retinal damage. Ensure they cover the eyes completely but do not obstruct the nose.
• Light Distance: Maintain proper distance from the light source. For LED and fluorescent lights, typically 10-15 cm above the baby. Follow manufacturer guidelines for specific units.
• During Treatment: Turn off phototherapy lights during feeding and when drawing blood samples for bilirubin testing. Remove eye shields during these breaks to allow parent-infant bonding.
• Duration: Treatment typically lasts 24-48 hours for mild cases but may extend up to 5-7 days for more severe hyperbilirubinemia. Continue until bilirubin levels drop significantly below treatment thresholds.
• Monitoring: Check the baby's temperature, feeding patterns, weight, urine output, and stool frequency. Watch for signs of dehydration or overheating.

Precautions and Safety Measures

Always use opaque eye shields with overhead phototherapy to protect the baby's retina. Although retinal damage from phototherapy has not been documented in clinical practice, eye protection remains a standard precaution. Ensure eye shields fit properly and do not cover the nose or interfere with breathing.

Monitor the baby's temperature regularly as phototherapy lights can cause warming, particularly with halogen lamps. Premature babies are especially vulnerable to temperature changes. Adjust the incubator or room temperature as needed and avoid placing halogen lights too close to the baby to prevent burns.

Phototherapy can increase insensible water loss through the skin. Ensure adequate feeding frequency and monitor for signs of dehydration such as decreased urine output, dry mouth, or sunken fontanelle. Some babies may require supplemental fluids.

Check the baby's skin regularly for any irritation, redness, or rash. While uncommon, some babies may develop temporary skin changes. Change diaper frequently as phototherapy often increases stool frequency.

• Verify light irradiance periodically using a radiometer to ensure therapeutic levels
• Replace bulbs or lamps according to manufacturer guidelines when hours expire
• Clean light surfaces regularly to maintain effectiveness
• Check electrical cords and connections for safety

Phototherapy should be used with caution or avoided in certain situations:

• Infants with congenital porphyria or family history of porphyria
• Babies taking photosensitizing medications
• Bronze baby syndrome - if it develops, discontinue phototherapy and consult physician

Potential Side Effects and Complications

Side Effect	Frequency	Management
Loose stools/diarrhea	Common	Normal response, ensure hydration and frequent diaper changes
Skin rash	Occasional	Usually resolves on its own, monitor closely
Temperature instability	Occasional	Adjust room temperature, monitor regularly
Dehydration	Occasional	Increase feeding frequency, may need IV fluids
Bronze baby syndrome	Very rare	Discontinue phototherapy, investigate liver function

This rare complication occurs when babies with elevated direct bilirubin and underlying liver problems develop a dark gray-brown discoloration of skin, urine, and blood serum during phototherapy. While the exact cause is not fully understood, it is thought to result from accumulation of bilirubin breakdown products that cannot be excreted properly.

The condition is usually reversible and resolves within weeks after stopping phototherapy. However, it requires investigation of liver function and may indicate an underlying hepatic disorder. Bronze baby syndrome is not a contraindication to continue phototherapy if the benefits outweigh the risks, but close monitoring is essential.

Frequently Asked Questions

No, phototherapy is completely painless. The baby may feel slightly warm from the lights but does not experience any discomfort from the light itself.

Bilirubin levels typically show a 30-40% decrease within 24 hours of starting intensive phototherapy. Most babies require treatment for 24-48 hours, though some may need longer depending on the severity.

With overhead lights, the baby needs to stay under the unit for maximum effectiveness, but you can hold the baby during feeding breaks. Fiber optic blankets allow you to hold your baby during treatment.

No, any temporary changes to skin appearance from phototherapy are completely reversible and resolve shortly after treatment ends.

Yes, home phototherapy is possible for stable, healthy term infants with mild to moderate jaundice using fiber optic blanket systems. This requires daily bilirubin checks, proper equipment, and reliable caregiver adherence. Home phototherapy is not suitable for premature babies or those with risk factors for complications.

No, breastfeeding should continue normally during phototherapy. In fact, frequent feeding helps lower bilirubin by increasing stool output. The lights can be turned off during feeding sessions.

A rebound bilirubin check is typically done 12-24 hours after stopping phototherapy to ensure levels remain safe. Some babies may experience a small rebound increase but this is usually not clinically significant.

No, there is no evidence that phototherapy causes cancer. The light used is in the visible spectrum, not ultraviolet, and extensive research over 60 years has not shown any link to cancer.

Device Maintenance and Safety

• Cleaning: Wipe down light surfaces and equipment with appropriate disinfectant between patients. Follow hospital infection control protocols.
• Light Irradiance Testing: Check light intensity regularly using a phototherapy radiometer. Most units should deliver at least 30 microwatts per square centimeter per nanometer for intensive phototherapy.
• Bulb Replacement: Replace fluorescent tubes after 2,000-3,000 hours of use, halogen bulbs after 450 hours, or as indicated by the timer. LED lights last 50,000 hours or more.
• Equipment Inspection: Check all electrical connections, cords, and switches regularly for wear or damage.
• Documentation: Maintain a log of bulb hours, maintenance dates, and equipment checks.

• Store in clean, dry environment away from moisture
• Protect fiber optic cables from sharp bends or crushing
• Keep eye shields clean and properly stored between uses
• Ensure spare bulbs are available and stored appropriately

• Verify all lights are functioning
• Check that eye shields are clean and intact
• Ensure proper distance settings
• Confirm timer is working if present
• Test any alarms or safety features

When to Seek Medical Attention

Additional Resources

• American Academy of Pediatrics Clinical Practice Guidelines on Hyperbilirubinemia Management
• Manufacturer operation manuals for specific phototherapy devices
• Hospital neonatal care protocols and guidelines
• National Institute for Health and Care Excellence (NICE) Neonatal Jaundice Guidelines

• American Academy of Pediatrics
• World Health Organization Newborn Health
• National Institutes of Health - MedlinePlus
• Manufacturer websites for specific product information

Source Information: This guide was compiled using research from peer-reviewed medical literature available through PubMed Central, clinical guidelines from medical organizations, and manufacturer technical specifications. Key references include studies on LED versus conventional phototherapy efficacy, fiber optic phototherapy effectiveness, and phototherapy safety profiles published in journals including The Journal of Pediatrics, Pediatrics, and the New England Journal of Medicine.

Content checked and reviewed by a pediatrician | Last updated: January 2026