This randomized controlled trial aims to evaluate the effects of oxytocin massage on breastfeeding self-efficacy and the milk ejection reflex among mothers experiencing insufficient milk supply in the early postpartum period. Insufficient milk supply is a common issue often linked to maternal stress, which can inhibit oxytocin release and negatively impact the milk ejection reflex and the mother's confidence in breastfeeding. By applying oxytocin massage to the thoracic paravertebral region, this study seeks to stimulate oxytocin release non-pharmacologically. The primary objective is to determine whether this intervention improves physiological milk flow and enhances maternal breastfeeding self-efficacy compared to routine postpartum care.

Breastfeeding is a fundamental public health intervention in protecting maternal and neonatal health, and the early postpartum period is particularly critical for the initiation and maintenance of lactation (WHO, 2023). Effective breastfeeding initiated in the first hours and days of life reduces neonatal mortality and positively affects long-term mother-infant health (Victora et al., 2023). However, physiological, psychological, and environmental factors experienced in the early postpartum period can negatively impact breastfeeding success. During this period, the mother's hormonal balance, birth experience, fatigue level, and emotional adaptation are among the main factors determining the quality of the breastfeeding process.

One of the most frequently reported problems by mothers in the early postpartum period is insufficient milk supply or perceived insufficient milk (Brown et al., 2022). Perceived insufficient milk is often related to maternal stress, anxiety, pain, and negative perceptions regarding the birth experience rather than objective milk production (Fallon et al., 2021). Increased stress levels can suppress oxytocin release through the hypothalamic-pituitary axis, thereby reducing the effectiveness of the milk ejection reflex (Uvnäs-Moberg et al., 2020). Inadequate realization of the milk ejection reflex can lead to delayed milk flow despite a feeling of fullness in the breast, making the mother's breastfeeding experience difficult. Recurrent negative experiences can lower the mother's perception of self-efficacy regarding breastfeeding (Dennis & Jackson, 2021).

The lactation process is regulated by the coordinated action of prolactin and oxytocin hormones. While prolactin is responsible for milk synthesis, oxytocin ensures the realization of the milk ejection reflex (Uvnäs-Moberg et al., 2020). Oxytocin is not only a peripheral hormone but also a neuropeptide that has stress-reducing and attachment-supporting effects at the central nervous system level. Increased oxytocin levels are reported to be associated with maternal relaxation, a sense of trust, and mother-infant bonding (Feldman, 2021). Therefore, non-pharmacological interventions that support oxytocin release can positively affect both physiological milk flow and the mother's psychological adaptation process.

Oxytocin massage is an intervention applied to the thoracic paravertebral region that aims to increase oxytocin release through afferent nerve stimulation. Although this method, frequently used in clinical practice, has been reported to have positive effects on milk production and milk volume (Kusumastuti et al., 2021; Pramono et al., 2022), it is observed that randomized controlled trials evaluating the effectiveness of the milk ejection reflex and its relationship with psychosocial variables together are limited. The fact that most existing studies have a quasi-experimental design highlights the need to strengthen the level of evidence.

Breastfeeding self-efficacy is based on the concept of self-efficacy, which is grounded in Bandura's social cognitive theory and expresses an individual's belief that they can successfully perform a specific behavior (Dennis, 2020). Self-efficacy is nourished by four main sources: performance accomplishments, verbal persuasion, vicarious experience (observational learning), and physiological-emotional states. Physiological difficulties and inadequacy in the milk ejection reflex experienced in the early postpartum period can negatively affect the mother's physiological-emotional state, leading to a decrease in self-efficacy perception (Brady et al., 2021). Low breastfeeding self-efficacy has been found to be associated with early cessation of breastfeeding (Fallon et al., 2021).

When the literature is reviewed, although there are studies examining the effect of oxytocin massage on milk volume, it is noteworthy that randomized controlled trials addressing the milk ejection reflex and breastfeeding self-efficacy together are limited. The lack of studies with a high level of evidence aimed at evaluating these variables together, especially in mothers experiencing insufficient milk supply, creates an important gap in terms of developing evidence-based midwifery practices. In this context, this study aimed to investigate the effect of oxytocin massage applied to mothers with insufficient milk supply in the early postpartum period on breastfeeding self-efficacy and the milk ejection reflex using a randomized controlled design. The study is expected to contribute to the literature regarding the effectiveness of non-pharmacological interventions for breastfeeding support in the early postpartum period.

Hypotheses:

H0a: Oxytocin massage applied to mothers with insufficient milk supply in the early postpartum period does not affect breastfeeding self-efficacy.

H1a: Oxytocin massage applied to mothers with insufficient milk supply in the early postpartum period leads to a change in the level of breastfeeding self-efficacy over time.

H0b: Oxytocin massage applied to mothers with insufficient milk supply in the early postpartum period does not affect the milk ejection reflex.

H1b: Oxytocin massage applied to mothers with insufficient milk supply in the early postpartum period leads to a change in the level of the milk ejection reflex over time.

Inclusion Criteria:

• Being 18 years of age or older
• Being in the early postpartum period (within the first 24-48 hours after birth)
• Having had a single, live birth via vaginal delivery or cesarean section
• Having a term (≥37 weeks) and healthy baby
• Being in the same room as the baby (rooming-in practice)
• Having started breastfeeding
• Reporting insufficient milk production or expressing difficulty with the milk let-down reflex
• Not having a cognitive, neurological, or serious psychiatric problem that would impede communication
• Voluntary participation in the study and providing written informed consent

Exclusion Criteria:

• Having given birth preterm (<37 weeks)
• Having given birth as a result of a multiple pregnancy
• Having been admitted to the neonatal intensive care unit (NICU)
• The baby having a congenital anomaly that prevents breastfeeding (e.g., cleft lip and palate)
• The mother having medical conditions that contraindicate breastfeeding (HIV infection, active tuberculosis, etc.)
• The mother developing serious postpartum complications (postpartum hemorrhage, eclampsia, serious infection, etc.)
• The presence of anatomical or pathological conditions related to the breast that may prevent breastfeeding (advanced mastitis, breast abscess, etc.)
• The presence of skin lesions, surgical incisions, or infections in the back that would prevent the application of oxytocin massage
• Failure to complete the intervention or wishing to withdraw from the study will be excluded.

Participation is restricted to biological females because the study specifically investigates maternal physiological processes related to the early postpartum period, lactation, the milk ejection reflex, and breastfeeding.

Individual participant data will not be shared to protect the privacy and confidentiality of the postpartum mothers involved in the study. The informed consent obtained from the participants strictly limits the use of their data to this specific research only. Furthermore, the institutional ethics committee approval does not cover public data sharing or secondary analysis by third parties.