Free bilirubin jaundice is a common condition in the neonatal period: 80% of newborns have some degree of hyperbilirubinemia within days of birth, but only 5-10% require treatment to prevent complications or to treat the cause of jaundice. The major complication is neurological toxicity, the most severe form of which is kernicterus, a severe and irreversible hyperbilirubinemic encephalopathy involving the basal ganglia. The main treatment for jaundice is phototherapy, which may or may not be combined with exchange transfusion in the most severe forms of jaundice caused by uncontrolled severe hemolysis. Phototherapy acts by interaction of light with bilirubin located in the skin, transforming it into photo-derivatives directly eliminated in the stool and urine. The hepatic stage of bilirubin transformation, limiting its elimination in newborns, is thus short-circuited. The interaction between bilirubin and light on the skin is maximal in the 460-490 nm spectrum. Phototherapy technology has evolved considerably since the discovery of its effectiveness by Dr. Cremer in 1958, with a constant progression in its effectiveness and indications. The light sources used in phototherapy devices are varied and today all use Light Emitting Diode (LED) technology. The models used today in phototherapy directly emit a blue wavelength, whose spectrum between 420 and 490 nm is the most effective. The effectiveness of the treatment also depends on the exposed skin surface, the homogeneity of the light intensity and the distance between the skin and the light source.

Other phototherapy equipment is also available, including the BiliCocoon® (Bilicocoon Bag, Eurocare®). This is a so-called "proximity" equipment. Thanks to the routing of the luminous flux by an optical fiber, the terminal light panel is put directly in contact with the baby's skin. This device allows an intensive and homogeneous radiation (35 µW/cm²/nm), and a wide coverage of the body surface (1200 cm²). The Bilicocoon® is a safe and controlled therapy that is performed in the mother's room, thus avoiding any separation, allows, during the treatment, to continue breastfeeding, is easy to install, does not require goggles and therefore no scope or hospitalization and thus reduces the workload of the nursing staff. A continuous treatment of 12 hours is required, interrupted only for the baby's change. Several sessions are sometimes necessary, and in case of failure, the child can be put under intensive phototherapy. The BiliCocoon® was implemented in our maternity hospital in August 2020 to avoid mother-child separations and to limit the number of hospitalizations in neonatology.

The objective of our study is to evaluate the impact on the number of hospitalizations in neonatology since its implementation, the failure rate (unchanged or increased bilirubinemia at the end of the Bilicocoon® session requiring a relai by intensive phototherapy) and the average length of stay of neonates treated for jaundice in the NDBS maternity unit of the GHPSJ. The secondary objectives are to evaluate the failure rate of Bilicocoon® : need for intensive phototherapy after a Bilicocoon® session (Bilicocoon® failure is defined by an unchanged or increased bilirubinemia at the end of the 12-hour session) and to evaluate the length of stay of children who had Bilicocoon® alone or intensive phototherapy alone for the same causes.

Inclusion Criteria:

• Newborn between 36 and 42 SA born between 01/08/2020 and 31/01/2022 at NDBS maternity
• AND in postpartum care with their mother, treated with phototherapy
• French speaking parents

Exclusion Criteria:

• Parents objecting to participation in the study
• Parents deprived of liberty
• Parents under guardianship or curatorship
• Children initially hospitalized in neonatology from the time of birth, regardless of the cause.

Newborn between 36 and 42 SA born between 01/08/2020 and 31/01/2022 at NDBS maternity and in postpartum care with their mother, treated with phototherapy