Preterm infants (28-37 gestation week) in the intervention group will receive 0.2 ml of breast milk intranasally three times a day for three days.

Preterm newborns in the control group will not receive any intervention.

The information in the "Physiologic Parameter Follow-up Form" will be recorded by the investigator just 5 minutes before the intervention. The researcher will drip 0.2 ml of breast milk at room temperature (approximately 22 °C) into the nose of the infant lying in the supine position, 0.1 ml in the right nose-0.1 ml in the left nose. 5 minutes after the intervention (T1), 15 minutes after the intervention (T2) and 30 minutes after the intervention (T3), the data in the "Physiologic Parameter Follow-up Form" will be recorded by the researcher. After intranasal breast milk administration, the baby will be fed by the neonatal nurse as in routine practice. The implementation of the intervention in the study will last for three days and this process will be repeated three times every day (09.00, 12.00 and 15.00).

The form developed by the researchers in line with the literature includes the identifying information of the preterm infant (gender, date of birth, gestational week at birth, mode of delivery, APGAR score, birth weight, postmenstrual age)

Cerebral rSO2 in the Physiological Parameter Monitoring Form will be measured 5 minutes before the intervention.

Oxygen saturation (sPO2) in the Physiological Parameter Monitoring Form will be measured 5 minutes before the intervention.

Heart rate in the Physiological Parameter Monitoring Form will be measured 5 minutes before the intervention.

Respiratory rate in the Physiological Parameter Monitoring Form will be measured 5 minutes before the intervention.

Intranasal breast milk content (fresh/thawed) in the Nutrition Follow-up Form will be recorded before the intervention.

Cerebral rSO2 in the Physiological Parameter Monitoring Form will be measured 5 minutes after the intervention.