The dependent variable of this research was breast milk production, while the independent variable was factors assumed to affect the increase of breast milk production on breastfeeding mothers, which is oxytocin massage and breast case. The sampling was done through Non-probability sampling and Purposive Sampling, obtaining 30 samples. The data collected using a questionnaire and analyzed using Mc Nemar test.

Based on Table 1 above, it is obtained that most breastfeeding mothers were at the age of 20–35 years old by 25 respondents (83.3%), were Senior High School graduates by 16 respondents (53.3%), were housewife by 19 respondents (63.3%), had two children by 12 respondents (40.0%), had children with normal birth weight by 26 respondents (86.7%), had full-term pregnancy by 29 respondents (96.7%), and had protruded nipple by 23 respondents (23.3%). Furthermore, it is also known that all breastfeeding mothers had normal nutrition based on the upper arm circumference, did not experience inflammation, and had cesarean section labor (100%).

The following Table 2 presents the difference in the increase of breastfeeding mothers’ breast milk production based on frequency, duration of breast milk provision, and baby's weight after the interventions of oxytocin massage and breast care in the working area of Lawanga Public Health Center, Poso District.

Before the intervention was performed, it was known that the production of breast milk was inadequate by 18 respondents, while the remaining 12 respondents’ were adequate, while after the intervention, it was obtained that seven respondents of the 18 respondents whose breast milk production was inadequate previously became adequate after the intervention, while the remaining 11 respondents were still inadequate. The statistic test result conducted indicates a p-value of 0.016, which means that it is less than 0.05. Thus, it can be concluded that oxytocin massage and breast care can increase breast milk production.

The statistical test conducted in this research obtained a p-value of 0.016, which indicates that oxytocin massage and breast care affected the increase of breast milk production. Theory suggests that oxytocin massage and breast care increase milk production. It was found that the increase in milk production in the breast care and oxytocin group (mean=17.37, SD=9.70) was greater than the control group (mean=1.58, SD=1.69), where the difference was statistically significant (p<0.001). There are two processes of breast milk formation; production and release. Through the stimulation on mothers’ nipples through babies’ mouths or massage on the back of the mothers, the oxytocin hormone will be released.

The purpose of the oxytocin massage is so that the mothers feel calm and relax so that they can increase the affection toward their baby and stimulates the release of oxytocin, which can accelerate the release of breast milk. Meanwhile, breast care will stimulate the lactiferous (prolactin hormone) to accelerate breast milk production as well. The combination of these two methods results in increased breast milk production through stimulation of touch to the breast and back of the mother which will stimulate the production of oxytocin which results in contraction of myoepithelial cells and increases the prolactin.7

This result is also consistent with previous studies showing that the intervention group produced more breast milk production of 3.74cc than the control group (2.04cc). Bivariate analysis performed showed a p-value of 0.001. Therefore, Endorphin, Oxytocin, and Suggestive Massage Stimulation (SPEOS) method concluded that those affected breast milk production in post-partum mothers.8 The smoother the breast milk production, the more breast milk produced, which then leads to the increase in baby's weight. Thus, through massage, the mother will feel relaxed, comfortable, lose the fatigue after labor and confident so that she will be able to produce breast milk exclusively to her baby.9 These results are also in line with the previous study (p<0.000), that oxytocin massage caused the increase of breast milk production of breastfeeding mothers at Public Health Center plus of Mandiangin Bukit Tinggi 2016.10

The lack and slow release of breast milk production can cause the mother to produce inadequate breast milk for her baby. In addition to prolactin hormone, the lactation process also depends on the oxytocin hormone, which is released from the posterior pituitary as a reaction to nipple suction.11 Oxytocin affected the myoepithelial cells surrounding the alveoli mammae so that the alveoli are contracted and release breast milk that has been secreted by the Mammae gland. Such oxytocin reflexes are affected by the mother's psychology.12 If there are anxiety, stress, and doubt, then the release of breast milk can be inhibited. So that one of the efforts to maintain the oxytocin hormone by giving back massage that can make the mother feels comfortable and relax.13,14

The results of this study clearly stated that there are differences in the results of pre and post interventions for oxytocin massage and breast care. Based on Table 2, it is known that during the pre-intervention, the breast milk production of 18 respondents was inadequate and while the other 12 respondents produced adequate breast milk. Meanwhile, during the post-intervention, among the 18 respondents whose previous breast milk production was inadequate, 7 of them became adequate after the intervention, while the remaining 11 respondents were still inadequate.

Oxytocin massage will stimulate the spinal cord; then, the neurotransmitter medulla oblongata will send a message to the hypothalamus. Thus, the posterior pituitary will secrete the hormone oxytocin, which causes the breasts to produce milk.15,16 The production of breast milk and the process of breastfeeding requires stimulation of the breast muscles to the breast glands for the contractions needed in the lactation process. Stimulation of the breast muscle can be done by giving breast care techniques.16–18

In addition, to increase the breast milk production, oxytocin massage and breast care also have many other benefits such as increasing the tightness of the breast and surrounding skin, relaxing the breast and breast area, preventing breast cancer, preventing the occurrence of breast milk blockage and maintaining breast hygiene especially on the nipples and many more.19,20 Based on the results of the research and theory above, there was a difference in increased breast milk production in breastfeeding mothers after oxytocin massage and breast care. Thus, it can be concluded that oxytocin massage and breast care can affect the increase of breast milk production in breastfeeding mothers at Lawanga Public Health Center, Poso District.