This is a randomized controlled experimental study evaluating the effects of oral motor intervention and chronobiological approach to feeding model applied to preterm infants on feeding readiness, transition to total oral feeding and body weight.

Premature birth is defined as birth occurring before the 37th week of gestation, and approximately 15 million babies are born this way worldwide each year. Premature babies experience feeding difficulties because their oral feeding skills, sucking-swallowing-breathing coordination, and oral structures are not fully developed. Their oral motor systems typically mature between 32-34 weeks of gestation. The development of the oral motor system is crucial for adequate nutrition, growth, and weight gain. Several methods are used to improve the oral motor development of premature babies. Oral motor interventions involve physical stimuli applied to intraoral structures such as the lips, tongue, cheeks, gums, and palate. These methods aim to increase the functional strength of oral muscles and target neuro-behavioral synergy.

Oral motor interventions applied in NICUs have been shown to accelerate the transition to oral feeding, increase weight gain, and shorten hospital stays in premature infants. Premature Infant Oral Motor Intervention (PIOMI) is one of the interventions applied in NICUs. Studies have shown that PIOMI is more effective than other interventions in this field. Furthermore, no negative side effects of PIOMI have been reported.

Breast milk is an ideal source of nutrition for the growth and development of preterm infants. It provides essential nutrients for the baby's growth and development, as well as containing biological cues that help regulate circadian rhythms. For the fetus, which has become accustomed to the mother's circadian rhythms during intrauterine life, it supports this transition process by providing similar cues after birth. The composition of breast milk can vary depending on gestational age, lactation stage, and pumping time. Differences are particularly observed between day and night breast milk in terms of circadian rhythms. Daytime milk contains higher levels of substances such as immune system-related nucleotides, interleukins, and antioxidants, while nighttime milk is rich in sleep-regulating components such as melatonin and tryptophan. This difference is important for the transmission of the mother's biological rhythms to the baby, contributing to the regulation of the baby's sleep-wake cycle and improving its environmental adaptation.

The chronobiological feeding model suggests that expressed breast milk be given in periods of day and night, or more specifically, in six-hour cycles, in accordance with the daily cycle. This approach aims to support the development of the infant's circadian rhythm through expressed breast milk in situations where breastfeeding is not possible. A review of the literature revealed no studies that combined PIOMI with chronobiological feeding. Therefore, this research was planned to determine the effects of oral motor intervention (PIOMI) and chronobiological feeding on feeding readiness, transition to total oral feeding and body weight in preterm infants hospitalized in the NICU.

Inclusion Criteria:

• Preterm infants with a postnatal age of 29-33 weeks,
• Whose vital signs and clinical condition have been stable for at least 24 hours,
• Whose APGAR score at 1 and 5 minutes (Activity-Pulse-Grimace-Appearance-Respiration) is 4 or higher.

Exclusion Criteria:

• Infants with major congenital anomalies (such as congenital heart disease, cleft palate, cleft lip) or birth trauma,
• Infants with RDS,
• Infants diagnosed with asphyxia,
• Infants with intraventricular hemorrhage,
• Infants with Neonatal Withdrawal Syndrome,
• Infants with Fetal Alcohol Syndrome,
• Infants included in the study group who develop any complications or whose stable condition deteriorates during the follow-up period,
• Infants with feeding intolerance or who are interrupted from feeding for more than 48 hours,
• Infants who develop sepsis,
• Infants who develop necrotizing enterocolitis,
• Infants receiving mechanical ventilation support,
• Infants who receive narcotic analgesia or sedation,

The data sets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request

6 months after publication

relevance to the topic of the study and approval of all co-authors within 1 month of receiving the request.