Cobedding consists of associating twins in a common cocoon in order to maintain links developed in utero and reduce the stress of premature birth. The aim of this randomized, controlled prospective study is to compare efficacy (in term of newborn daily weight gain) and safety of cobedding versus single-bedding of preterm twins.

Randomization will occur during the first 96 hours after birth.Twins randomized in the cobedding arm will be kept in the same cocoon until maximum 37 amenorrhea weeks. Each day, parameters (weight gain, …) will be registered.At two years old, neuromotor development of twins will be estimated by Brunet-Lezine test.

Inclusion Criteria:

• At time of inclusion, twins must have been separated since less than 96h following birth.
• twins born between 30 to 34 weeks of gestation
• no severe congenital pathology
• hospitalized at the intensive neonates care unit
• Parents having given their non-opposition to this study within the 96 hours following twins birth -Time length of cobedding estimated by the investigator to be of three weeks -

Exclusion Criteria:

Inclusion criteria not fulfilled

• safety reasons
• prolonged lack of comfort clinically harmful for the newborn as per investigator conclusion.