Hyperbilirubinemia is defined as the presence of bilirubin in the serum of newborns at levels exceeding the normal range. It is the most common problem among healthy newborns, with an incidence of approximately 40% to 60% in full-term infants. The primary cause is the immature bilirubin metabolism in newborns, leading to the accumulation of excess bilirubin in the blood, which in turn results in a temporary yellowing of the skin and sclera, known as jaundice. Physiological jaundice in full-term newborns typically appears 24 to 72 hours after birth, peaking on days 4 to 5. Studies have shown that neonatal jaundice is a leading cause of readmission after discharge.

Phototherapy is the most effective and safest treatment for neonatal hyperbilirubinemia. It takes advantage of bilirubin's sensitivity to light, converting bilirubin into water-soluble conjugated bilirubin, which is then excreted through bile and urine, thereby reducing total bilirubin levels. The most effective light during phototherapy has a wavelength of 400 nm to 520 nm and an intensity of at least 30 microW/cm²/nm, with at least 80% of the infant's body surface area exposed.

This study aims to investigate whether using aluminum foil reflective covering around the phototherapy incubator can enhance the effectiveness of light treatment for jaundice in infants, thus potentially reducing the duration of phototherapy required.

Inclusion Criteria:

1. Newborns who are admitted to the neonatal ward for examination and treatment due to jaundice levels reaching the treatment threshold.
2. Term babies below 14 days of age (gestational age of 37 weeks or greater).
3. No evidence of hemolysis

Exclusion Criteria:

1. Infants with serum bilirubin levels close to the exchange transfusion limit
2. Hemolytic disease (Ex: G6PD)
3. Congenital anomalies
4. Elevated direct bilirubin
5. Infants with abnormal liver function or biliary structure
6. Infants who receive Cardiopulmonary Resuscitation after birth or suspected perinatal asphyxia