The study will be conducted with the Crossover Randomized Controlled Method. The infants who have attained oral feeding in the neonatal intensive care unit will be divided into two groups via randomization in the computer environment. After the randomization, kangaroo care will be applied to the infants in Group 1 during the first feeding hour when they are included in the study and they will be breastfed by their mothers without any other application during the next feeding. On the other hand, no application will be performed on the infants in Group 2 during the first feeding hour when they are included in the study and kangaroo care will be applied to them during the second feeding hour. The infants in both groups will be breastfed by their mothers during the feeding hours.

Test weighing is a feeding evaluation method which is used for evaluating the increase in infant's body weight and the amount of food intake before and after breastfeeding. Each gram is evaluated to be equivalent to one cc breast milk. The aim of the study is to evaluate the effect of kangaroo care applied to the preterm infants that have attained oral feeding and are breastfed by their mothers, on their physiological parameters, feeding condition and body weight increase. After weighing the infant only in his/her diaper before the feeding and applying kangaroo care in which skin-to-skin contact will be provided for half an hour, the mother will breastfeed the infant. The infant will be weighed once again after the feeding without diaper change and the effect of kangaroo care on test weighing and physiological parameters during the feeding process will be evaluated. Sample size of the study has been determined by the power analysis, in line with the results obtained from the studies which have been conducted using a similar research method. According to the analysis results, it has been calculated as 23 for each group and 46 in total. Parents of the infants meeting the study inclusion criteria will be informed both in written and verbally and then the study will be conducted with mothers who agree to participate in the study with their infants.

Inclusion Criteria:

- Agreeing to participate in the study for parents.

The inclusion criteria for infants were as follows;

• Attaining to oral feeding by the physician in the neonatal intensive care unit
• Being born at 26-36+6 gestational week which is determined according to the mother's last period cycle
• Being at 32-39+6 postmenstrual week during the time they are included in the study
• Having body weight of 1500 grams and above
• Being breastfed at least once
• Having no health problems other than being preterm

Exclusion Criteria:

The exclusion criteria for infants were as follows;

• Suffering from gastrointestinal, neurological or genetic diseases (such as necrotizing enterocolitis, intracranial bleeding, hydrocephalia, omphalocele, down syndrome, gastroschisis) and other diseases
• Having a condition obstructing oral feeding (such as cleft palate, cleft lip, facial muscle paralysis, craniofacial abnormalities etc.)
• Receiving oxygen support