The investigators will conduct a prospective cohort without change in care.

Following classic patient admission in involved departments, the investigating team moves to the department to collect data.

The measurements and informations collected are no different from those taken in the context of normal care.

All anthropometric measurements correspond to recommendations of good practice. Anthropometric measurements will be carried out by the healthcare team.

With collected data the investigators will evaluate undernutrition for each child, according to the 2 diagnostics methods.

For any diagnosis of undernutrition, the department dietician will be alerted so that the patient can be taken care of so it is done normally.

Data collected are as follows:

Simple demographic characteristics: Age, sex, departmentsand principal diagnosis Anthropometry: weight, height, brachial perimeter, head circumference Birth weight and date of term of pregnancy. Clinical history: all pathologies or clinical events that may be related to a weight variation.

Assessment of ingesta. A non-opposition will be asked