Oral motor Stimulation (OMS) and an Supplemental Nursing System (SNS) were applied to preterm infants in the experimental group.

The clinic's routine feeding protocol was applied to the babies in the control group.

OMS and an SNS were applied to preterm infants in the experimental group. Oral stimulation intervention provides assisted movement to activate muscle contraction and provides movement against resistance to build strength. The cheeks (internal and external), lips, gums, tongue, and palate were stimulated by finger-stroking following the protocol. OMS consisted of intra (oral region) and peri-oral stimulation (around the oral region). The OMS was administered three times a day by a nurse, from the day of initiation of oral feeding to the day of independent oral feeding 15 minutes before the feeding schedule. A bottle/container was filled with breast milk before the process and given to the baby via SNS while the baby was holding the mother's breast. The SNS consists of a syringe/container and a feeding catheter. One end of the feeding probe is inside the syringe/container, while the other end of it is fixed to the mother's nipple using plaster.

Transition time to oral feeding is the time that the preterm baby outgrew gavage feeding and fed with complementary nutritional support, and it was evaluated as days in the study.

The transition time to full breastfeeding is the duration from the day that the preterm baby started oral nutrition until the day they started breastfeeding

. The oral nutrition body weight is the weight of preterm babies when they started oral nutrition after gavage.

The full breastfeeding body weight is the weight in grams of preterm babies when they started feeding from the breast alone

The duration of discharge is the number of days between the admission of preterm babies to intensive care and their discharge

The oral nutrition body weight is the weight of preterm babies when they started oral nutrition after gavage.

Heart rate

respiratory rate