月経カップ：ライフサイクル・アセスメント

課題

タンポンやナプキンなどの生理用品は、2019年に全世界で260億米ドル（1ドル=110円として2兆8600億円）の負担を消費者に強いている（Imarc, 2020）。同時に、米国では毎年498億個のタンポンや生理用ナプキンとその包装材が埋立地や下水道に捨てられており、経済的にも環境的にもコストが高い。月経カップは、その両方の問題を解決できるのだろうか？　月経衛生の改善は、国連の持続可能な開発目標「No.５ジェンダー平等を実現しよう」と「No.６安全な水とトイレを世界中に」の2030年までの目標達成に貢献できるのだろうか？　私たちは、ジェンダー平等と環境の持続可能性という2つの社会善を推進することができるのだろうか？

方法：環境ライフサイクル・アセスメント

ジェンダード・イノベーション：

• 1. 月経カップは環境に優しく、国連の持続可能な開発目標「No.６安全な水とトイレを世界中に」に貢献する。
• 2. 月経カップはジェンダー平等を支え、国連持続可能な開発目標「No.５ジェンダー平等を実現しよう」に貢献する。
• 3. 月経カップは月経がある人たちの健康を支え、国連の持続可能な開発目標「No.３すべての人に健康と福祉を」に貢献する。
• 4. 月経カップは開発途上国における学校への出席維持を支え、国連持続可能な開発目標「No.１貧困をなくそう」に貢献する。

The Challenge

Menstrual hygiene products, such as tampons and pads, cost consumers US$ 26 billion globally in 2019 (Imarc, 2020). At the same time, 49.8 billion tampons and sanitary pads plus their packaging end up in landfills or sewer systems each year in the U.S. The cost of these products to the consumer and the environment is high. Can the menstrual cup help solve both problems? Can a change in menstrual hygiene sanitation help achieve the United Nations' Sustainable Development goals #5 "gender equality" and #6 "clean water and sanitation" by the year 2030? Can we promote two social goods: both gender equality and environmental sustainability?

The gendered innovation here is the menstrual cup. Although originally patented in 1867 (US 70843 A) and again in 1932 and 1937, menstrual cups have only recently become popular.

A menstrual cup:

• 1. is a bell-shaped and made of medical-grade silicone or natural latex. It is inserted into the vagina to collect (not absorb) menstrual fluid.
• 2. can be left in place for up to 12 hours.
• 3. may last for 2-4 years; some may last up to 10 years.
• 4. is reusable. A user will likely need between 4 and 32 cups in a lifetime, depending on the type used.
• 5. must be washed between uses and be sterilized at the end of the period. Cups can be sterilized in boiling water, microwaves, or, when traveling, with sterilizing tablets.
• 6. is not biodegradable but can be recycled at a specialty recycling center (Thiele, 2016).
• 7. is multifunctional. It can deliver contraception, vaginal medication, and, when a microbicide is added, protect against STIs and HIV. It may also function as a fertility aid by retaining semen close to the cervix (North & Oldham, 2011).
• 8. can be used by all people who menstruate.
• 9. cannot be used by people who have undergone genital cutting and been sewn closed—as is the case for 200 million girls and women worldwide (WHO, 2018).
• 10. is a safe option for menstruation management. It does not cause mechanical harm to the vagina or cervix nor does it increase the risk of infection compared to pads and tampons (van Eijk et al., 2019).
• 11. is an effective option for menstruation management. Leakage has been shown to be similar or less with a menstrual cup than with disposable pads/tampons (van Eijk et al., 2019).

N.B. Menstruation is a fact of life. We want to make clear that menstrual products constitute only a small proportion of waste created globally each year. The purpose of this case study is to encourage manufacturers to provide products that are safe and effective—from the point of view of environmental impact, cost, and health.

1: Menstrual Cups are Good for the Environment

supporting the UN Sustainable Development Goals #6 Clean Water and Sanitation

Traditional hygiene products, such as tampons and pads, are a burden to the environment. Altogether a menstruator likely uses around 15,000 sanitary pads or napkins, creating some 250-300 pounds of waste, over a lifetime (Stein, 2009, 238).

The figure (right) compares the environmental impacts of four products—o.b. tampons (non-reusable, no applicator), Tampax tampon (non-reusable, applicator), Softcup (non-reusable), and DivaCup (reu sable) as indexed by 'global warming potential'. Overall, reusable menstrual cups have the lightest environmental touch (Weir, 2015).

This study also analyzed material impacts by abiotic depletion, fossil fuel depletion, acidification, eutrophication, and waste production. In each category, reusable menstrual cups were the most environmentally friendly.

These data, however, do not factor in all environmental costs across all stages of production, distribution, use, and disposal. What is needed is a life-cycle assessment for each product from raw material extraction, material production, parts production, and assembly to its use and final disposal. For example, cotton used in many tampons and napkins requires significant land use, water, and pesticides to grow.

The environmental impact of pads and tampons is growing. In India, for example, only 12% of the 335 million women currently use sanitary napkins (Geertz et al., 2016). What will happen when 100% of those in their reproductive years achieve sanitary protection across India, Africa, and China (the last of which currently manufactures 85 billion sanitary napkins each year—Yang, 2016)?

Some traditional sanitary products are biodegradable, but the vast majority are made from synthetic materials that decompose slowly. Some 90 percent of sanitary napkins are plastic (Women's Environmental Network, 2017). It is estimated that the 20 billion pads, tampons, and applicators accumulating in North American landfills every year will take 500 to 800 years to fully biodegrade (Geertz et al., 2016, 12).

2: Menstrual Cups are Good for Gender Equality

supporting the UN Sustainable Development Goals #5 Gender Equality

In 2019, Menstrual hygiene products, such as tampons and pads, cost consumers US$ 26 billion globally (Imarc, 2020). These costs magnify gender inequality given the gender pay gap (women in the U.S. overall earn 80.5 cents on men's dollars). These costs especially burden low-income people, creating a barrier to accessing menstrual sanitary products. U.S. aid programs, such as Medicaid, do not support menstrual products, even though the FDA considers them medical devices (Kosin, 2018).

Although the cup is more expensive upfront (roughly U.S. $15-25 depending on the brand), because it is reusable it saves thousands of dollars over a lifetime. In qualitative studies, participants using menstrual cups cite monthly savings from not needing to buy pads or laundry soap (van Eijk et al., 2019). In addition, emerging evidence indicates that menstrual cup use in resource-poor areas might decrease the need for transactional sex to purchase feminine hygiene products (van Eijk et al., 2019).

A conservative estimate would project the cost of menstrual cup use to be as low as US$180 for cups (assuming 3 cups per decade x 4 decades) and not more than $430 (assuming 8 cups x 4 decades) plus government tax (in countries that still charge tax). The initial investment may be high because of the possible need to purchase several cups before finding the right fit.

3: Menstrual Cups are Good for Health

supporting the UN Sustainable Development Goals #3 Good Health & Well-Being

The U.S. FDA recommends but does not require tampon and sanitary pad makers to disclose the materials and chemicals in their products (FDA, 2005). People may be unaware of potential toxins, in particular dioxin, contained in these products (WHO, 2016). Although the FDA considers the threat from dioxins in tampons "negligible," no studies have tested diffusion of dioxins from tampons in vivo or the accumulative impact of exposure over a lifetime (Weir, 2015; Dudley et al., 2018). Further, tampons and pads carry the threat of toxic shock syndrome (Wendee, 2014).

Menstrual cups, by contrast, are hypoallergenic and bear a very low reported risk of TSS; medical grade silicone does not significantly support the growth of the bacterium S. aureus, associated with TSS (Tierno, 1994; North & Oldham, 2011; van Eijk et al., 2019).

A cluster randomized control study in rural Western Kenya found other health benefits. Menstrual cups can also be used to deliver contraception, vaginal medication, and, when a microbicide is added, protection against STIs and HIV. (North & Oldham, 2011; Phillips-Howard et al., 2016).

4: Menstrual Cups Help Sustain School Attendance in Developing Countries

supporting the UN Sustainable Development Goals #1 No Poverty

Menstrual hygiene products can be prohibitively expensive in low-income settings, such as parts of the U.S., sub-Saharan Africa, and rural India. As a result, people may use reusable cloth, newspaper, or simply stay home (Sommer & Sahin, 2013).

A number of recent projects have studied the impact of introducing menstrual cups to school-age children in South Africa, Uganda, Kenya, and rural India. Participants were provided a cup, education on menstruation and cup use, and a bar of soap each month plus information on how to disinfect cups (although many lacked the simple equipment required to boil cups—Hyttel et al, 2017). Studies found that, with proper education and training, participants successfully used the cups, and often preferred them to pads (Howard et al., 2011; Beksinska et al., 2015; Mason et al., 2015).

Cups had several advantages: menstrual cups reduced fear of leaking, increased confidence, comfort, mobility, independence, and allowed active school attendance or work during menstruation; a UK study found that menstrual cup use was associated with a significant decrease in the number of product changes in one cycle when compared to tampons and pads (van Eijk et al., 2019).

The cost of any menstrual hygiene products is prohibitive in many areas. Some cup brands, such as Femmecup, Ruby Cup, Keeper, Diva cup, Lunette, Softcup, and My Own Cup, have programs to donate to people in need.

Conclusions

Menstruation is a fact of life. But the way societies manage and respond to menstruation can and are being changed. Proper management requires changing attitudes and making menstruation a topic people feel comfortable talking about and taking action on menstruation. Education, support, and sanitation infrastructure are all important. The goal is comfortable, convenient products that are safe for people and the environment.

Next Steps

• 1. For environmental sciences, comparative life-cycle assessment is required for each type of menstrual product. These analyses should factor in all environmental costs across all stages of production, distribution, use, and disposal. On packaging, manufacturers should provide results from such a life-cycle analysis for the specific product, indicating environmental impacts from raw material extraction, material production, parts production and transportation, and assembly to its use and final disposal.
• 2. Product designers can provide alternatives to traditional menstrual hygiene products. Current initiatives:
  • a. Thinx and Dear Kate produce high-tech washable underwear that absorbs menstrual fluid. The fabric is anti-microbial, moisture-wicking, absorbent, and leak resistant (https://www.shethinx.com; http://www.dearkate.com). TomboyX and other companies also gender-inclusive period underwear in sizes appropriate also for transgender men and others.
  • b. Sustainable Health Enterprises train people to make pads out of banana trunk fibers (http://sheinnovates.com).
  • c. AFRIpads produce washable reusable pads across Africa (https://www.afripads.com).
  • d. BeGirl makes reusable underwear with a mesh pocket that can be filled with any readily available, safe absorbent material (https://www.begirl.org).
  • e. Femme International's Femme Health Management initiative distributes menstrual cups, menstrual education, and other hygiene products in East Africa (https://www.femmeinternational.org/our-work/).
• 3. Politicians should support human rights with respect to menstruation. Human Rights Watch and WASH United have stated that the biological fact of menstruation, the necessity of managing menstruation, and society's response to both are linked to human rights and gender equality (Human Rights Watch, 2017). Chief of the UN Human Rights Office Economic and Social Issues Section, Jyoti Sanghera, adds that "stigma around menstruation and menstrual hygiene is a violation of several human rights" (UNOHCHR, 2014).
• 4. Foundations can support access to sustainable menstruation products. The Bill and Melinda Gates Foundation, for example, advocates for addressing menstruation sustainably and at scale (Geertz et al, 2016). This includes safe and consistent access to products, supportive communities, education and awareness, and excellent sanitation facilities and services.