The goal of this clinical trial is to compare sleeping in a SNOO Smart Sleeper bassinet (SNOO) with sleeping in traditional bassinet conditions in premature infants. The main questions it aims to answer are:

1. Do preterm infants who sleep in the SNOO have more quiet sleep?

2. Do preterm infants who sleep in the SNOO have improved vital signs?

   • Participants will spend two separate three-hour periods sleeping in either a SNOO (which plays white noise and rocks from side-to-side) or in a SNOO that remains off (does not play white noise and does not move). There will be at least one week separating these sleep assessments.
   • Participants will have their sleep stage and vital signs monitored (heart rate and oxygen levels).
   • Participants will also wear two stickers on their forehead that measure brain oxygen levels (NIRS) and brain waves (EEG).

There is a chance that the infant may experience more restful sleep and improved vital signs during the 2 sleep assessments.

Sleep plays an important role in the brain growth and development of preterm infants. Neonatal sleep is made up of three stages of sleep: quiet sleep, active sleep, and transitional sleep. Poor sleep can be a result of premature birth itself as well as from simply being in the neonatal intensive care unit (NICU) environment. The interruptions that these infants are exposed to include frequent cares, physical exams, lights, and noises.

The investigators are interested in the potential positive effects on sleep of recreating the environment of the womb. The SNOO is a bassinet that uses the combination of a secure swaddle, white noise, and gentle rocking movements to mimic the conditions that infants were exposed to in the uterus before being born. The investigators are interested in studying how recreating this environment of "within the womb" impacts the sleep-wake cycles of premature infants. To do this, the investigators will measure the amount of time that premature infants spent asleep versus awake while in the SNOO through behavior observations, electroencephalogram (brain activity monitoring), and vital signs. The investigators hypothesize that sleeping in the SNOO will increase the amount of time that the premature infants spend in quiet sleep and will improve their vital signs.

Inclusion Criteria:

• Inpatients at the Morgan Stanley Children's Hospital NICU.
• Singleton gestation.
• Gestational age 28w0d to 36w6d at birth.
• Postmenstrual age greater than 35 weeks at the time of the intervention.
• Weight greater than 1.8 kg and less than 11.3 kg.
• Stable thermoregulation in an open crib.
• Stable respiratory status on room air (no nasal cannula or CPAP).
• Normal head ultrasound (if obtained).

Exclusion Criteria:

• Congenital brain or spinal anomalies.
• Intracranial hemorrhage.
• Severe encephalopathy.
• Known or suspected genetic syndromes that could result in cerebral dysfunction.
• Airway anomalies that could result in sleep-disordered breathing.
• Bleeding diatheses.
• Status post surgery or minor surgical procedures (i.e. inguinal hernia repair, circumcision).
• Fetal opioid exposure.
• Administration of sedating agents over the past 24 hours.
• Ability to independently roll to hands and knees.

During sleep time (approx 3 hours) at baseline sleep assessment

All infants were discharged from the NICU after the 1st sleep assessment and were therefore not able to do a 2nd sleep assessment as outlined in the protocol, so the results presented in this record only reflects data collected from one 3-hour sleep assessment.