In this episode of Behind the Latch, Margaret Salty interviews Maya Nakamura, CNM, PhD(c)—a midwife researcher from Sapporo, Japan—about her work on nipple trauma and her recent study on silver nipple protectors. Maya shares how years of bedside experience, watching mothers struggle with painful nipple damage, pushed her into research and innovation in clinical assessment (including AI-based image analysis) and practical tools that may reduce pain and promote healing.
Together, they explore how culture, access, and methodology shape nipple-trauma research; what we do and don’t yet know about silver nipple protectors; and how IBCLCs can translate emerging evidence into compassionate, realistic care for families. Maya also talks about the realities of conducting trials in Japan (declining birth rates, ethics, and single-site constraints), and why standardized outcome measures are critical for future meta-analyses.
They discuss:
- Why study nipple trauma? Night-shift realities, mother distress, and the limits of common “friction-reduction” hacks that sparked formal inquiry.
- Silver nipple protectors 101: what they are, how they’re used postpartum, and potential mechanisms (barrier + moisture + antimicrobial silver).
- Study design trade-offs: why a non-randomized comparative design with historical controls was chosen, and steps taken to minimize bias.
- Key findings from Maya’s trial: reductions in severe nipple trauma indicators and day-4 pain—alongside a clean safety profile in the study setting.
- Real-world considerations: availability in Japan, cost barriers (≈¥10,000) and ideas like unit-level lending to improve access.
- What’s next: the call for standardized criteria, longer follow-up, comparisons with other treatments, and the promise (and limits) of AI for consistent nipple-trauma classification.
Maya emphasizes a practical, parent-centered approach: protect the nipple, relieve pain, and sustain breastfeeding—while staying honest about evidence gaps and equity barriers in accessing devices and follow-up care.
Guest Info
Maya Nakamura, CNM, PhD(c)
- Midwife & doctoral researcher (Sapporo, Japan)
- Focus: nipple-trauma classification, wound-care adjuncts, and AI-assisted assessment in lactation care.
Publications:
Nipple Skin Trauma in Breastfeeding Women During Postpartum Week One. , Breastfeeding Medicine, Nakamura M, Asaka Y, Ogawara T, Yorozu Y, 2018 Sep;13(7):479-484.
https://www.researchgate.net/publication/326818739_Nipple_Skin_Trauma_in_Breastfeeding_Women_During_Postpartum_Week_One
・An evaluation of the signs of nipple trauma associated with breastfeeding: A Delphi Study, Journal of human lactation, Maya Nakamura, Yoko Asaka, 2022 Feb; 38(3) 548–558. DOI: 10.1177/08903344221076527
journals.sagepub.com/home/jhl
https://journals.sagepub.com/doi/10.1177/08903344221076527
・Effectiveness of moisturizing therapy in treating nipple trauma: a systematic review protocol, BMJ Open, Nakamura M, Luo Y, Ebina Y. 2024;14:e083389. doi: 10.1136/bmjopen-2023-083389
https://bmjopen.bmj.com/content/14/9/e083389.long
・Systematic Review on the Efficacy of Moisturizing Therapy in Treating Nipple Trauma and Nipple Pain. Journal of Human Lactation. Nakamura M, Luo Y, Ebina Y. 2025;41(1):39-53. doi:10.1177/08903344241301401
https://journals.sagepub.com/doi/10.1177/08903344241301401
・Development of Nipple Trauma Evaluation System With Deep Learning. Journal of Human Lactation. Nakamura M, Sugimori H, Ebina Y. 2025;41(1):105-114. doi:10.1177/08903344241303867
https://journals.sagepub.com/doi/10.1177/08903344241303867
・Role of Silver Nipple Protectors in Treating Nipple Trauma: A Non-Randomized Comparative Trial. J Hum Lact. Nakamura M, Sugimori H, Asaka Y, Ebina Y. 2025 Aug;41(3):382-391. doi: 10.1177/08903344251342564.
https://journals.sagepub.com/doi/10.1177/08903344251342564
・Feasibility and Acceptability of a Deep-Learning-Based Nipple Trauma Assessment System for Postpartum Breastfeeding Support. Healthcare, Nakamura, M., Sugimori, H., & Ebina, Y. (2025). 13(17), 2091. https://doi.org/10.3390/healthcare13172091
Transcript:
Where are you located and where are you working?
My name is Maya Nakamura. I live in Sapporo, the capital city of Hokkaido in northern Japan.
I am a third-year doctoral student and also a midwife. Before starting my doctoral program, I worked as a nursing and midwifery faculty member, and after graduation I plan to return to academia. As a midwife, I used to work in hospitals, but now I practice independently, visiting families at home to support pregnant women, new mothers, and their babies.
What brought you to this work?
I became a midwife simply because I love babies. I am also a mother of four children, which is quite unusual in Japan where most families have only one or two. My youngest is still an infant, and I am currently breastfeeding.
Your body of research centers around nipple damage. Can you tell me where this desire to study nipple damage in breastfeeding mothers came from?
When I was working as a hospital midwife, I often saw mothers crying at night because of painful nipple damage. They wanted to continue breastfeeding but felt they had no choice but to stop. At that time, senior midwives used to give polyester film to reduce friction, but I wondered whether it really worked and what the evidence was. That curiosity led me to pursue research, and it became the reason I entered a master’s program.
Silver nipple protectors are becoming more popular in the US. I see them frequently with my patients and my students often ask about them. What led you to focus your research on silver nipple protectors, and why do you think there was a need to study them in a Japanese population?
I noticed that silver nipple protectors are common in the US. I also saw a booth for them at the last ILCA conference, which showed me how much attention they are receiving. In Japan, however, they are almost unknown. I first came across the 2015 paper by Marrazzu et al., which really surprised me because of the unique appearance of the device. I imported one, and when I gave birth myself, I tried it and felt it worked. When I introduced it at my clinic, both mothers and midwives responded positively. That experience convinced me that Japanese mothers could also benefit from them.
Your study used a non-randomized comparative design with historical controls. Can you explain why this design was chosen and how you addressed potential limitations?
The choice was practical. First, there are ethical challenges in Japan with providing different interventions to women admitted at the same time in the same hospital. Second, silver nipple protectors are not common here, and introducing them across multiple facilities is very difficult. Japan also faces declining birth rates, which makes it hard to recruit large samples. For these reasons, I conducted the study in one clinic where silver protectors had already been used, and I used historical data as the control.
To minimize bias, I collected data from facilities of similar size and with comparable quality of midwifery care.
In both this study and the study used for the control sample you classified nipple trauma into specific signs such as erythema, swelling, scabbing, and blistering. How did you determine which signs to focus on, and what did you find most challenging about measuring trauma consistently?
The classification was based on my earlier research. I collected about 750 photographs of nipple trauma over time and analyzed them, which led me to develop a seven-category system. Using this system, we evaluated erythema, swelling, scabbing, and blistering in this study. The method itself was not so difficult, but subjective judgment is always a limitation. Recently, I have also used AI-based image analysis to classify nipple trauma, which I believe reduces subjectivity.
One of your key findings was that silver protectors reduced severe trauma and nipple pain by day 4 postpartum. You mention that it’s unclear whether the benefits come from the silver itself, the moisture effect, or both. Based on your findings, what do you think might be the most important mechanism at work?
As I wrote in my paper, it is not clear whether the benefit comes from the silver itself, the moisture effect, or both. My personal view is that it is likely a combination of both.
No adverse effects were reported in your trial. Were there any concerns from participants or staff about using silver, particularly regarding safety or potential impact on breast milk?
Because the study was conducted in a clinic that had already used silver protectors for several years, staff did not express concerns. We excluded women with very sensitive skin or known metal allergies. Participants generally had no safety concerns either, although some mentioned that the protector sometimes slipped off during sleep, or that the edge could press against the breast when it was engorged.
What do you see as the next steps in studying silver nipple protectors—do you envision randomized controlled trials, long-term follow-up, or comparisons with other common treatments like lanolin or hydrogel pads?
A full randomized controlled trial may be difficult in Japan due to ethical and clinical issues. In my opinion, one of the main problems in nipple trauma research is that different studies use different evaluation criteria, which prevents meta-analysis. I believe the next step is for researchers to use a standardized classification—such as my seven-category system—so that we can build evidence together.
What is next for you in terms of research?
I am currently working on using AI to classify nipple trauma. I think this technology can be very beneficial for the next generation of mothers. At the same time, human touch and care from midwives will always be essential. My goal is to combine AI with hands-on midwifery support to provide more comprehensive care.
Where can my listeners learn more about you and the work that you're doing?
Please take a look at my publications. I have written seven papers in English so far.
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🎙 Hosted by: Margaret Salty
🎧 Guest: Maya Nakamura
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