Comparison of The Effects of Initial Oral Feeding by Cup and Bottle-Feeding of Preterm Infants

Criteria for Sample Selection * Being at the ≤34th gestational week according to the last menstrual period of the mother of the preterm * Being at the ≥30th postmenstrual week on the date of inclusion in the study * Having a body weight of 1000 grams or more on the date of inclusion in the study * Switching from enteral feeding to oral feeding for the first time with the joint decision of the physician and nurse * Breastfeeding * Showing physiological and behavioural signs indicating that the infant is ready for oral feeding (tolerating full enteral feeding, exhibiting sucking behaviour, opening the mouth by responding to stimuli around the mouth, normal physiological values \[HR of 120-160/min, SpO2≥90\], maintaining alertness, keeping the body in flexion posture) * Having parental consent for inclusion in the study and an informed consent form signed by parents Exclusion Criteria * Having diagnostic criteria for severe bronchopulmonary dysplasia (≥30% O2 requirement and/or positive pressure requirement at the 36th postmenstrual week or at discharge in preterm infants with a gestational age of \<32 weeks; ≥30% O2 requirement or positive pressure requirement at the 56th postnatal day or at discharge in preterm infants with a gestational age of ≥32 weeks) * Having an anomaly such as cleft palate, cleft lip * Having gastrointestinal, neurological or genetic disease (NEC, IVH, hydrocephalus, asphyxia, Down syndrome, short bowel syndrome, etc.)