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Research article

Research priorities for improving menstrual health across the life-course in low- and middle-income countries

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Article: 2279396 | Received 04 Jul 2023, Accepted 31 Oct 2023, Published online: 27 Nov 2023

ABSTRACT

Background

Research on menstrual health is required to understand menstrual needs and generate solutions to improve health, wellbeing, and productivity. The identification of research priorities will help inform where to invest efforts and resources.

Objectives

To identify research priorities for menstrual health across the life-course, in consultation with a range of stakeholder groups from a variety of geographic regions, and to identify if menstrual health research priorities varied by expertise.

Methods

A modified version of the Child Health and Nutrition Research Initiative approach was utilized to reach consensus on a set of research priorities. Multisector stakeholders with menstrual health expertise, identified through networks and the literature, were invited to submit research questions through an online survey. Responses were consolidated, and individuals were invited to rank these questions based on novelty, potential for intervention, and importance/impact. Research priority scores were calculated and evaluated by participants’ characteristics.

Results

Eighty-two participants proposed 1135 research questions, which were consolidated into 94 unique research questions. The mean number of questions did not differ between low- and middle-income country (LMIC) and high-income country (HIC) participants, but significantly more questions were raised by participants with expertise in mental health and WASH. Sixty-six participants then ranked these questions. The top ten-ranked research questions included four on ‘understanding the problem’, four on ‘designing and implementing interventions’, one on ‘integrating and scaling up’, and one on ‘measurement’. Indicators for the measurement of adequate menstrual health over time was ranked the highest priority by all stakeholders. Top ten-ranked research questions differed between academics and non-academics, and between participants from HICs and LMICs, reflecting differences in needs and knowledge gaps.

Conclusions

A list of ranked research priorities was generated through a consultative process with stakeholders across LMICs and HICs which can inform where to invest efforts and resources.

Responsible Editor Maria Emmelin

Background

Menstrual health has received increased attention in recent years as an important component of public health [Citation1,Citation2]. Research in low- and middle-income countries (LMICs) – largely descriptive studies – has described girls’ need for information related to menstrual health and the impacts of poor menstrual health on their health, wellbeing, and education [Citation3–5]. A small number of recent trials have evaluated the impact of menstrual products and puberty education on girls’ school attendance, educational performance, sexual and reproductive health (SRH), and wellbeing [Citation6–12]. Other studies have focused on understanding the menstrual self-care practices and menstrual health challenges of women and girls in humanitarian contexts, as well as the acceptability of specific menstrual products [Citation13–15] and policy considerations [Citation16] in such settings. More recently, studies have started to describe challenges for adult women [Citation17–21] and marginalized populations [Citation22–27], the relationship between menstrual health and mental health [Citation28], and measures for menstrual health research [Citation5,Citation29–31]. The evidence on menstrual health has been consolidated into a growing body of systematic reviews, including reviews focused on specific geographies [Citation32–34], populations (e.g. girls with disabilities [Citation35], and those who are displaced [Citation32,Citation36]), measures of exposures and outcomes [Citation30,Citation37], interventions (e.g. menstrual cups, reusable menstrual pads) [Citation38,Citation39], and outcomes (e.g. knowledge and understanding, health, and social wellbeing) [Citation4,Citation34,Citation40–42].

The identification of research priorities is an important process to help researchers, programmers, practitioners, policymakers, and funding agencies decide on which specific areas to invest their efforts and resources. In 2014, research priorities on menstrual hygiene management (MHM) among schoolgirls in LMICs were identified by an expert group as part of ‘MHM in Ten,’ an initiative that sought to set the agenda for overcoming challenges related to menstrual health and hygiene (MHH) faced by this population and for identifying the evidence needed to improve girls’ experiences of menstruation and education [Citation1,Citation3]. As evidenced by its extensive citation history and the substantial number of relevant research outputs since 2014, it is clear that the prioritization effort has positively impacted the trajectory of the field, which has developed rapidly in the past nine years. Several identified priorities have been acted upon, including the need to strengthen the evidence base, with over 50% of all menstrual health literature published after 2015 [Citation4]. Other priorities have also seen progress, including the need for standardized menstrual measures [Citation31,Citation43] and definitions [Citation30,Citation44,Citation45], and the need for a research consortium, which has begun to take shape under the umbrella of the Global Menstrual Collective (GMC). The GMC is a collaborative network whose aim is to bring together partners in MHH to amplify efforts and reduce duplication for mainstreaming menstrual health across health, education, gender, and water, sanitation, and hygiene (WASH).

Given the evolution of the field, it is therefore timely to reassess the research priorities for improving menstrual health to guide the field. Further, as the focus of efforts to address menstrual health has expanded beyond schoolgirls to include girls who are out-of-school, as well as women and others who menstruate, there is a need to identify research priorities to address the needs of all who menstruate across the life-course in varying contexts around the world [Citation46]. According to the WHO, a life course approach to health aims to ensure people’s well-being at all ages by addressing people’s needs, ensuring access to health services, and safeguarding the human right to health throughout their lifetime [Citation47].

Thus, the objective of this study is to identify research priorities for menstrual health across the life-course in LMICs, in consultation with a range of stakeholder groups from a variety of geographic regions. This study additionally aims to understand if and how research priorities differ across sectors, specifically between academics and those outside of academia.

Methods

This research was undertaken by members of the Global Menstrual Collective’s Research and Evidence Group, comprising researchers, consultants, programmers, policymakers, and funding agencies working in the field of menstrual health.

We used a modified version of the Child Health and Nutrition Research Initiative (CHNRI) approach to reach consensus on a set of research priority questions. The CHNRI approach is a transparent and structured process for ranking the relative importance of competing research priorities to help decision-makers effectively allocate limited resources to address a health problem, e.g. by reducing morbidity and mortality, improving wellbeing and quality of life, and addressing inequities [Citation48,Citation49]. It has been used to reach consensus on research priorities for numerous health topics, including adolescent health [Citation50], adolescent sexual and reproductive health [Citation51], and family planning [Citation52]. In short, the CHNRI approach involves three phases: 1) identifying individuals with expertise on a topic; 2) asking these individuals to propose research questions related to the topic; and 3) asking them to rate the proposed research questions against a set of criteria. These ratings are subsequently used to calculate a composite Research Priority Score for each question, which are then ranked. The adapted CHNRI approach used in this study is described in detail below.

Phase 1: identification of individuals with expertise in menstrual health

To be as inclusive as possible, a snowball and self-selection approach was used for this study. Phase I consisted of identifying ways of reaching individuals from various stakeholder groups with expertise in policy, programming, financial support, and/or research related to menstrual health around the world. This included (i) menstrual health networks, coalitions, and consortia (e.g. the Menstrual Health Hub, the African Coalition for Menstrual Health Management, the MHM in Ten Expert network, Water Supply and Sanitation Collaborative Council and the GMC Collective, the Menstrual Cup Collaboration, and WASH United’s Menstrual Hygiene Day), (ii) published researchers, and (iii) funders from past or current funding calls.

Phase 2: identification of research questions on menstrual health

An initial correspondence was sent to (i) menstrual health networks, coalitions, and consortia, (ii) known academic researchers likely to be missed from (i), and (iii) funders identified in Phase 1. This correspondence included information about the study, an invitation to participate, and an electronic survey (SurveyMonkey, Palo Alto) through which they could propose research questions regarding menstrual health across the life-course. The invitation email was sent in September 2020 with two reminders sent fortnightly. The survey was closed in October 2020.

Participants were prompted to propose research questions after they read an information sheet explaining the nature and purpose of the exercise, they had consented, and had provided demographic information about their sector of work (e.g. academia, UN-agency, non-governmental organization) and geographic areas of residence and work Research questions spanned three domains (each with several sub-domains), as guided by the CHNRI approach:

  1. Understanding the problem: questions to illustrate the experiences of those who menstruate, explore risk and protective factors for menstrual health, and test impacts and consequences of poor menstrual health. Such questions could utilize a range of methodologies, from descriptive epidemiology to ethnographic research.

  2. Designing and implementing interventions: questions which relate to (i) discovery of new interventions, (ii) development and testing the effectiveness of interventions, (iii) evaluations of the costs of interventions, (iv) evaluations of the delivery of interventions (including acceptability, adoption, appropriateness, feasibility, fidelity, coverage, and reach), and (v) evaluations of the sustainability of interventions. Such questions could utilize intervention effectiveness research and implementation research.

  3. Integrating and scaling up interventions: questions which relate to integrating menstrual health interventions into health, education, WASH, or social services and to taking menstrual health interventions to scale. Such questions could include implementation research and policy and systems research.

Exemplar questions for each domain and sub-domain were included in the survey to provide further clarity for the participants.

Participant responses were downloaded into spreadsheets, and free texts were collapsed to aggregate group data. A core team of four members of the Global Menstrual Collective’s Research and Evidence Group then iteratively categorized and consolidated the questions based on themes. Further ordering of questions between domains and sub-domains was undertaken where relevant. Duplicates were removed, as were questions covering unrelated topics. An extra domain, Measurement & Research, was included as numerous questions on this topic were suggested by participants. Similar questions were condensed together to derive a smaller number of amalgamated research questions (Table S1). Once the full set of consolidated questions was developed, a meeting with the GMC’s Research and Evidence Group was held to review and agree upon a final list of research questions to be used in Phase 3.

Phase 3: prioritization of the proposed research questions on menstrual health

Following the CHNRI approach, Phase 3 of the process involved rating each of the proposed research questions on a standard set of criteria to generate a composite Research Priority Score for each question. Discussion among the GMC’s Research and Evidence Group raised concerns about the length of the survey that would be required to accomplish this, given the large number of research questions that were proposed by participants in Phase 2. Further, the relevance of the five criteria typically proposed by the CHNRI approach (i.e. clarity, answerability, importance/impact, implementation, equity) was questioned for this specific topic; in particular, there was concern for potential confounding due to the explicit mention of ‘equity’ in multiple questions. To address these concerns, the five criteria were modified in line with the CHNRI approach, which suggests that the priority setting process should list possible criteria appropriate to their specific context and may merge criteria, where appropriate [Citation49]. Thus, three criteria – novelty, potential for implementation, and importance/impact () – were agreed upon, with the CHNRI approach’s standard scoring system of yes, no, or undecided. Due to its length, the survey was split into two sections comprising 43 and 51 research questions.

Table 1. Criteria used to score the proposed research questions and their definitions.

Invitations were sent to (i) menstrual health networks, coalitions, and consortia, (ii) published researchers, and (iii) funders identified in Phase 1 to score the proposed research questions, again using an electronic survey (SurveyMonkey, Palo Alto). An invitation email was sent in June 2021 with two reminders sent fortnightly. The survey was closed in July 2021. Similar to the prior survey, participants read the information sheet, consented, and provided information on their sector and area of work.

Participant responses were downloaded into spreadsheets, cleaned, and imported into IBM SPSS version 28 (Armonk, N.Y.). A variable was created to indicate if participants had responded to individual research priority questions. The number of responses per participant and per research question were counted. For participant demographic information, frequency distributions of characteristics of the participants were conducted. We also conducted an analysis of variance to test if there was a significant difference between the mean number of questions, across the three domains and overall, provided by participants with seven or more years of experience with MHH compared with those with less experience. Means, standard deviations, and levels of significance reached were generated, with a p-value of ≤ 0.05 considered significant.

For ranking of the research questions, a score of 100 points was attributed to ‘yes’, 50 points to ‘undecided’, and 0 points to ‘no’. A total Research Priority Score (RPS) was then assigned for each research question by computing the mean score across the three criteria. RPSs were then ranked from highest to lowest, overall and within each domain. RPSs were also assessed based on the profile of the participants, e.g. by their sector of work, stakeholder group, and years working in menstrual health.

Ethical considerations

The project was approved by the Liverpool School of Tropical Medicine’s Research and Ethics Committee (ID# 20–055), and it was granted exemption from review by the Human Reproduction Programme Research Protocol Review Panel and the WHO Ethics Review Committee (ID# ERC.0003407). Potential participants were informed that their participation was voluntary, and they were free to stop responding to the questions at any time. Participants were required to indicate their consent using a checkbox before the survey commenced.

Results

Characteristics of phase 2 participants

A total of 82 participants responded to the Phase 2 survey and proposed research questions on menstrual health (). The majority were female (89%) with 33% and 28% aged 25–34 years and 35–44 years respectively. The highest proportion (N = 50, 61%) originated from HICs, with 29% from Europe; LMICs were represented by 30 (39%) of participants, with 27% of all participants from sub-Saharan Africa. The highest proportion of participants worked in non-government organization (NGOs) and international NGOs (43%) or in academia (35%). A higher proportion of participants from HIC were academics, compared with LMIC (48% versus 15.6%, p = 0.002), while the reverse was true for NGOs, where 34% were from LMIC and 16.0% from HIC (p = 0.05). A third of participants worked globally, over half (58%) worked in sub-Saharan Africa, and 35% worked in east and southern Asia. Sixty-two percent of participants reported their area of expertise lay in sexual and reproductive health (SRH). Over one third (38%) of participants had worked in the field of menstrual health for seven years or longer.

Table 2. Participant characteristics (n = 82).

Proposed research questions

A total of 1135 research questions were proposed by the 82 participants that responded to the Phase 2 survey, with a mean of 13.8 (standard deviation [sd 9.9]; median 11) research questions proposed per participant ( and Table S2). The greatest number of research questions proposed were on ‘understanding the problem’ (521 by all 82 participants; mean 6.4 per participant), followed by ‘designing and implementing interventions’ (451 by 69 participants, mean 6.5 per participant). Integrating and scale up questions were proposed by fewer participants (145 questions, among 54 participants, mean 2.7), and 15 participants suggested 18 other research questions (mean 1.2). Participants with seven or more years of experience in menstrual health (n = 51) proposed more research questions (average 17.6), compared with those with fewer years of experience (n = 31; average 11.7) (Table S3). Participants with WASH expertise (N = 35) provided significantly more questions (16.77, sd 9.72) compared with those without WASH expertise (N = 47; 11.85, sd 9.63) (Table S4). Participants working in the mental health sector (N = 11) also proposed more research questions (mean 19.7, sd 12.9) than those working in other areas (combined mean 13.17, sd 9.25). The differences among stakeholder groups were less pronounced, with no significant differences. Evaluation of the research priority questions posed by LMIC (N = 32) compared with HIC (N = 50) participants found no significant differences in the mean number of research questions, with a mean of 15.03 (sd 9.82) suggested by LMIC participants compared with a mean of 13.29 (sd 10.02; p = 0.442) from HIC participants.

Table 3. Overview of the proposed research questions.

As previously described, the proposed research questions were consolidated into a final list of 94 unique research questions. A breakdown of the number of research questions per domain and sub-domain is provided in .

Table 4. Overview of the consolidated list of research questions.

Characteristics of phase 3 participants

A total of 66 participants completed the Phase 3 survey, contributing to the prioritization of the proposed research questions (). In the interest of ensuring anonymity of the data, it was not possible to confirm that the participants who responded to the survey in Phase 2 were the same as those who responded to the survey in Phase 3. The majority were female (80%), with 26% and 27% aged 25–34 years and 45–54 years respectively. The highest proportion (61%) resided in HICs, with 32% of the participants from Europe; LMICs were represented by 39%, with 18% of the participants from Asia. The highest proportion of participants worked in NGOs or international NGOs (38%) and academia (33%). An equal proportion of participants from LMIC and HIC were academics (34.6% and 32.5%, respectively). Over a third (39%) of participants worked globally, 38% worked in sub-Saharan Africa, and 30% worked in east and south Asia. Sixty-five percent of participants reported working in SRH. Over half (51%) had worked in the field of menstrual health for seven years or more.

Prioritized research questions

The highest ranked research question by RPS among all participants was ‘What indicators are optimal for assessing menstrual health over time (e.g. related to norms, education, health, rights, etc.)?’ It was ranked highest according to non-academic participants, and second highest according to academic participants.

The full list of ranked research questions is available in Table S5. The top ten-ranked research questions are listed in . They include four questions on ‘understanding the problem’, four on ‘designing and implementing interventions’, one on ‘integrating and scaling up’, and one on ‘measurement and research’. We found a high level of agreement on these ten questions, with total RPS ranging from 0.913 to 0.956 (out of a possible 1). Of note, the difference in RPS between the top ten-ranked research questions and those subsequent was not substantial, pointing to the high prioritization of many questions beyond those included only in this abbreviated list (). Thus, the top five-ranked research questions in each domain, ranked according to their RPS, are listed in .

Figure 1. Research priority scores and overall rank.

Figure 1. Research priority scores and overall rank.

Table 5. Top 10-ranked research questions, by research priority score.

Table 6. Top five-ranked research questions in each domain, by research priority score.

When examining the top five-ranked research questions by individual scoring criteria, as opposed to the overall RPS, it is notable that the top five-ranked questions in the criteria ‘potential for implementation’ are in the overall top ten ranked questions by RPS, as are the top five ranked questions in the criteria ‘importance/impact’, except for one question (). In both criteria, three out of the top five-ranked questions are in the domain ‘understanding the problem.’ Additionally, it is noteworthy that the top five-ranked questions in the criteria ‘novelty’ did not include questions from the domain on ‘understanding the problem’ and instead included questions from the domains of ‘designing and implementing interventions’, ‘integration and scale-up’, and ‘measurement and research.’

Table 7. Top five research questions ranked by individual scoring criteria.

When examining the average RPS by domain, we found a similar level of prioritization of the domains among all participants, with average RPS ranging from 0.833 to 0.862 (). However, when comparing the average RPS by domain among academics compared with those outside of academia, it is noted that both academics and non-academics gave highest prioritization to ‘integrating and scaling up’. For academics this was followed by ‘understanding the problems’, ‘designing and implementing interventions’, and ‘measurement and research’, while for non-academics this was followed by ‘measurement and research’, ‘understanding the problem’, and ‘designing and implementing interventions’. Likewise, when comparing the average RPS by domain among participants from HICs vs LMICs, it is noted that participants from LMICs gave highest prioritization to ‘measurement and research’, followed by ‘integrating and scaling up’, ‘designing and implementing interventions’, and ‘understanding the problem’, while participants from HICs gave highest prioritization to ‘integrating and scaling up’, followed by ‘understanding the problem’, ‘measurement and research’, and ‘designing and implementing interventions’.

Table 8. Average research priority scores, by domain, stakeholder group, and country of origin.

When comparing the top ten-ranked research questions among academics vs. those not working in academia, there were notable differences (). First, the lists have only three questions in common (out of a total of 18 unique questions in the two lists): one regarding the optimal indicators for assessing menstrual health, one regarding interventions to address norms and attitudes about menstruation, and one regarding interventions to manage menstrual pain. Second, the top ten-ranked questions among non-academics included more questions in the domain on ‘understanding the problem’ (n = 4) than those among academics (n = 1). The top ten-ranked questions among academics, meanwhile, included more questions in the domain on ‘designing and implementing interventions’ (n = 7) than those among non-academics (n = 4).

Figure 2. Comparison of the top ranked research questions, among academics vs. non-academic.

Figure 2. Comparison of the top ranked research questions, among academics vs. non-academic.

Finally, when comparing the top ten-ranked research questions among participants from HIC vs. LMICs, there were also considerable differences (). First, the lists only had one question in common (out of a total of 19 unique questions in the two lists): that regarding the optimal indicators for assessing menstrual health. Second, the top ten-ranked research questions among participants from HICs included more questions in the domain on ‘understanding the problem’ (n = 5) than those among participants from LMICs (n = 1). The top ten-ranked questions among participants from LMICs meanwhile, included more questions in the domain of ‘integrating and scaling up’ (n = 3) than those among participants from HICs (n = 0).

Figure 3. Comparison of the top ranked research questions, among participants from HICs vs. LMICs.

Figure 3. Comparison of the top ranked research questions, among participants from HICs vs. LMICs.

Discussion

This study used a modified version of the CHNRI approach to identify research priorities on menstrual health across the life-course in LMICs, moving beyond the previous research priority setting exercise conducted in 2014 that focused on schoolgirls [Citation3]. In doing so, it incorporated input from 82 participants across all continents with expertise in policy, programming, financial support, and/or research related to menstrual health.

Overall, the study identified a greater number of research questions in the domains of ‘understanding the problem’ and ‘designing and implementing interventions’, with a higher prioritization of those research questions, compared with questions on ‘integration and scale-up’ and ‘measurement and research’. This suggests that there are still many knowledge gaps related to understanding the menstrual experiences of women, girls, and others who menstruate, and in identifying and assessing the most effective interventions to meet their needs. These two domains also align with previous research priority-setting exercises, which specifically noted ‘the need for a strong evidence base’, and included illustrative questions related to understanding the problem and developing interventions [Citation3,Citation53]. Until these gaps are addressed, it appears that stakeholders perceive questions regarding ‘integration and scale-up’ to be premature. The lower prioritization of questions on ‘integration and scale-up’ may also reflect the composition of stakeholder groups that participated in this study, as only a small proportion of participants represented international agencies, government, and funding agencies.

Despite there being fewer ‘measurement and research’ questions identified and prioritized overall, the top-ranked research question identified in this study was ‘What indicators are optimal for assessing menstrual health over time?’ The 2014 research priority setting exercise focused on schoolgirls also highlighted a broad need for standardized measures, and specifically noted a need for identifying indicators for national-level monitoring for assessing changes over time [Citation3]. Having a standardized set of indicators is critical even to answer the other research questions in this list. A standardized set of indicators would allow for comparison of menstrual health issues across and within different populations worldwide, which could help researchers, implementers, and funders to target their efforts where they are needed most. Since this study was initiated, progress on indicators has been made [Citation43]. Specifically, a shortlist of priority indicators for monitoring girls’ menstrual health at the national level [Citation31] and a list of potential indicators for monitoring menstruation among those who work outside the home have been published [Citation54]. Additionally, in 2021, the Joint Monitoring Programme for Water Supply, Sanitation, and Hygiene – custodians of monitoring data for SDG targets 6.1 and 6.2—included a set of harmonized menstrual health indicators as part of the first dedicated section on menstrual health in the regular reporting on household drinking water, sanitation, and hygiene [Citation55].

This study identified that the top research priorities were not limited to one area of expertise (e.g. education, health, WASH etc.) but were distributed across topics. For example, the top ten-ranked research priorities include questions related to menstrual pain, socio-cultural drivers of menstrual health, menstrual products, and participation in school and work. This indicates that research gaps exist in multiple domains of menstrual health, which will need to be addressed through collaborative efforts across all areas of expertise. Further, they identify a strong need to promote equity by understanding the specific menstrual needs and experiences of underserved populations (e.g. those living with HIV, those with disabilities, those who are incarcerated, those experiencing homelessness, those who have experienced Female Genital Mutilation (FGM), trans and gender non-binary persons), and identifying effective interventions to meet those needs. Finally, the difference in RPS between the top 10-ranked research questions and those following was not substantial, pointing to the high prioritization of many questions beyond those included only in this abbreviated list.

This study also identified important differences in the top ten-ranked research priorities among academics and those working outside of academia, and those from HICs and LMICs. In part, the different priorities may reflect what the two stakeholder groups see firsthand as challenges and needs in their day-to-day work. It may also reflect an important need for improved knowledge sharing between stakeholder groups. For example, while sorting through the proposed research questions in Phase 2, the GMC’s Research and Evidence Group – which itself was largely composed of academics – felt that many of the proposed questions already had a substantial amount of evidence in the published literature. As such, strong effort is needed to ensure that research evidence is not confined to academic literature, but rather that findings and recommendations are written, translated, and disseminated purposefully and meaningfully to others working in the field of menstrual health, e.g. through educational programmes, through liaison with governments to support legislation. On the other hand, it is possible that those directly involved in the implementation of menstrual health interventions have generated substantial learnings on what the problems are, what interventions work to address them, and how to deliver them effectively in various contexts, but have not formally publishing these learnings. They would thus see those domains as a lower priority despite limited published evidence. More effort is needed to ensure that these learnings are documented, integrated into an evidence base on menstrual health, and equally valued and disseminated across stakeholder groups. Finally, these differences may also reflect variations in what stakeholder groups view as worthy of investment from a limited pool of resources. For example, academics may feel that there is insufficient evidence to invest resources on an intervention, while non-academics may approach such decision-making from a different lens, such as that of human rights.

Strengths and limitations

This study has several limitations. First, whilst the open invitation along with snowballing technique opened our survey to a wide audience, participants were permitted to self-select, and stringent criteria were not used to evaluate their eligibility for inclusion. As a result, it is possible that the study was affected by non-response bias, and some participants may not have had sufficient expertise to be considered an ‘expert’ in menstrual health. Second, many participants began the surveys in Phases 2 and 3 but did not complete them. The format of the online survey did not allow participants to view the whole document; instead, they had to complete each page before the next page was revealed. This meant participants were unable to decide in advance whether the survey was appropriate or of interest to them until after they had completed their demographic details. A formal analysis of the barriers to completion was not possible, but we hypothesize that the length of the surveys – particularly that used in Phase 3, which had a total of 94 questions each requiring consideration of three criteria – may not have been user-friendly for such a wide audience. This may also have contributed to the high level of consistency in scores across the three criteria. Further, although this was intended to be a global exercise, it was only conducted in English; thus, non-English speaking menstrual health experts may not have been able to participate and, among those who did, some may not speak English as their primary language. This may explain in part the absence of substantial participation from Latin America and the Caribbean and the Middle East, and under-representation from countries in Asia. It is also important to note that the survey required participants to have stable internet connectivity, as it was not available to download; this may also have undermined participation in LMICs. We also note that direct contact was made with well-known academic researchers who were likely to be missed from membership of consortia and acknowledge this was not a systematic capture of all academic researchers internationally. As a result, the findings from this study may not perfectly reflect the opinions of all menstrual health experts. Finally, as noted above, in the interest of ensuring anonymity of the data, it was not possible to confirm that the participants who responded to the survey in Phase 2 were the same as those who responded to the survey in Phase 3. As a result, the perspectives and expertise of the participants may have varied throughout the process.

Nevertheless, this study also has many strengths. While research priorities were previously generated on menstrual health among schoolgirls [Citation3], this is the first study to generate research priorities on menstrual health across the life-course in LMICs. This is particularly timely given the growing momentum among researchers, implementers, and activists in recognizing the importance of menstrual health to female empowerment and gender equity. Additionally, the study utilized a modified CHNRI approach, which is a well-respected and widely utilized systematic approach to research priority setting with transparent criteria. The study also incorporated input from participants representing a wide range of countries, sectors, stakeholder groups, and years of experience in menstrual health. Finally, this study included several sub-analyses to (1) understand the characteristics of those who did and did not complete the surveys and the implications of this for others seeking to use the CHNRI approach to generate research priorities, and (2) to understand how the research priorities differ by stakeholder group and country of origin, along with the implications for knowledge dissemination and translation between academics and non-academics and those in HICs and LMICs.

Conclusions

In conclusion, this study aimed to generate research priorities on addressing menstrual health across the life-course in LMICs. It identified that the largest number of questions identified as research priorities belong to the domains of ‘understanding the problem’ and ‘designing and implementing interventions’, suggesting that there are still many knowledge gaps in understanding the menstrual experiences of women, girls, and others who menstruate, as well as in understanding the most effective interventions to meet their needs. This study also identified that the top research priorities were not limited to one area of expertise (education, health, WASH, etc.) but were distributed across issues, indicating that research gaps exist in multiple domains of menstrual health which will require collaborative efforts to address. Further, this study identified a strong need to promote equity by understanding the specific menstrual needs and experiences of underserved populations.

As menstrual health continues to gain attention and emphasis as an important component of public health, it is hoped that these research priorities can be utilized by policymakers, programmers, researchers, and funders to guide future research in this area. Recognizing that research priority setting is a dynamic process, it is also hoped that these research priorities will be revisited in an iterative manner as the field continues to evolve.

Author contributions

The study was conceptualized by PPH and MP. Study design was developed by all authors. Data were collected and analyzed by MP PPH LM BC BT. The manuscript was drafted by MP PPH LM and BT. All authors reviewed and edited the manuscript.

Ethics and consent

The project was approved by the Liverpool School of Tropical Medicine’s Research and Ethics Committee (ID# 20–055), and it was granted exemption from review by the Human Reproduction Programme Research Protocol Review Panel and the WHO Ethics Review Committee (ID# ERC.0003407). Potential respondents were informed that their participation was voluntary, and they were free to stop responding to questions at any time. Participants were required to indicate their consent using a checkbox before the survey commenced.

Paper context

In 2014, research priorities were identified on menstrual hygiene management among schoolgirls in LMICs. This paper identifies an updated set of research priorities for menstrual health across the life-course in LMICs, in consultation with various stakeholders from different geographic regions. The breadth of research priorities indicates the topic remains under-researched and greater evidence is needed for policy and action. Additionally, the different responses between academics and non-academics suggests a need for improved knowledge sharing.

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Acknowledgments

We are grateful to all members of the GMC’s Research & Evidence group for their contributions to this study. Cheryl Giddings is thanked for her administrative support. We also thank the many colleagues managing collaborations and various consortia and hubs that provided a conduit to forward the surveys involved in this study to their colleagues and constituents, to ensure a wide representation of participants around the world and in different sectors. We thank all participants who so carefully generated and scored these research questions. We are grateful to Virginia Kamowa and Therese Mahon from the Global Menstrual Collective who facilitated funding to support this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/16549716.2023.2279396.

Additional information

Funding

This work was funded through the Global Menstrual Collective. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • Sommer M, Caruso BA, Sahin M, Calderon T, Cavill S, Mahon T, et al. A time for global action: addressing girls’ menstrual hygiene management needs in schools. PLoS Med. 2016;13:e1001962. doi: 10.1371/journal.pmed.1001962 PubMed PMID: 26908274.
  • Sommer M, Hirsch JS, Nathanson C, Parker, RG. Comfortably, safely, and without shame: defining menstrual hygiene management as a public health issue. Am J Public Health. 2015;105:1302–17. doi: 10.2105/AJPH.2014.302525 PubMed PMID: 25973831.
  • Phillips-Howard PA, Caruso B, Torondel B, Zulaika G, Sahin M, Sommer M. Menstrual hygiene management among adolescent schoolgirls in low- and middle-income countries: research priorities. Glob Health Action. 2016;9:33032. doi: 10.3402/gha.v9.33032 PubMed PMID: 27938648; PubMed Central PMCID: PMCPMC5148805.
  • Hennegan J, Shannon AK, Rubli J, Schwab KJ, Melendez-Torres GJ, Myers JE. Women’s and girls’ experiences of menstruation in low- and middle-income countries: a systematic review and qualitative metasynthesis. PLoS Med. 2019;16:e1002803. doi: 10.1371/journal.pmed.1002803 Epub 2019 May 17. PubMed PMID: 31095568; PubMed Central PMCID: PMCPMC6521998.
  • Mehjabeen D, Hunter EC, Mahfuz MT, Mobashara M, Rahman M, Sultana F. A qualitative content analysis of rural and urban school students’ menstruation-related questions in Bangladesh. Int J Environ Res Public Health. 2022;19. doi: 10.3390/ijerph191610140 Epub 2022 Aug 16. PubMed PMID: 36011779; PubMed Central PMCID: PMCPMC9408576.
  • Phillips-Howard P, Nyothach E, Ter Kuile F, Omoto J, Wang D, Zeh C, et al. Menstrual cups and sanitary pads to reduce school attrition, and sexually transmitted and reproductive tract infections: a cluster randomised controlled feasibility study in rural western Kenya. BMJ Open. 2016;6:e013229. doi: 10.1136/bmjopen-2016-013229
  • Montgomery P, Hennegan J, Dolan C, Wu M, Steinfield L, Scott L, et al. Menstruation and the cycle of poverty: a cluster quasi-randomised control trial of sanitary pad and puberty education provision in Uganda. PLoS One. 2016;11:e0166122. doi: 10.1371/journal.pone.0166122 PubMed PMID: 28002415; PubMed Central PMCID: PMCPMC5176162.
  • Kansiime C, Hytti L, Nalugya R, Nakuya K, Namirembe P, Nakalema S, et al. Menstrual health intervention and school attendance in Uganda (MENISCUS-2): a pilot intervention study. BMJ Open. 2020;10:e031182. doi: 10.1136/bmjopen-2019-031182 Epub 2020 Feb 7. PubMed PMID: 32024786; PubMed Central PMCID: PMCPMC7044877.
  • Austrian K, Kangwana B, Muthengi E, Soler-Hampejsek E. Effects of sanitary pad distribution and reproductive health education on upper primary school attendance and reproductive health knowledge and attitudes in Kenya: a cluster randomized controlled trial. Reprod Health. 2021;18:179. doi: 10.1186/s12978-021-01223-7 Epub 2021 Sep 2. PubMed PMID: 34465344; PubMed Central PMCID: PMCPMC8406733.
  • Sivakami M, Maria van Eijk A, Thakur H, Kakade N, Patil C, Shinde S, et al. Effect of menstruation on girls and their schooling, and facilitators of menstrual hygiene management in schools: surveys in government schools in three states in India, 2015. J Glob Health. 2019;9:010408. doi: 10.7189/jogh.09.010408 Epub 2018 Dec 14. PubMed PMID: 30546869; PubMed Central PMCID: PMCPMC6286883.
  • Zulaika G, Nyothach E, van Eijk AM, Wang D, Opollo V, Obor D, et al. Menstrual cups and cash transfer to reduce sexual and reproductive harm and school dropout in adolescent schoolgirls in western Kenya: a cluster randomised controlled trial. EClinicalMedicine. 2023;65:102261. doi: 10.1016/j.eclinm.2023.102261 Epub 2023 Oct 20. PubMed PMID: 37860578; PubMed Central PMCID: PMCPMC10582356.
  • Mehta SD, Zulaika G, Agingu W, Nyothach E, Bhaumik R, Green SJ, et al. Analysis of bacterial vaginosis, the vaginal microbiome, and sexually transmitted infections following the provision of menstrual cups in Kenyan schools: results of a nested study within a cluster randomized controlled trial. PLoS Med. 2023;20:e1004258. doi: 10.1371/journal.pmed.1004258 Epub 2023 Jul 25. PubMed PMID: 37490459; PubMed Central PMCID: PMCPMC10368270.
  • VanLeeuwen C, Torondel B. Exploring menstrual practices and potential acceptability of reusable menstrual underwear among a Middle Eastern population living in a refugee setting. Int J Womens Health. 2018;10:349–360. doi: 10.2147/IJWH.S152483 Epub 2018 Jul 24. PubMed PMID: 30034256; PubMed Central PMCID: PMCPMC6047600.
  • Schmitt ML, Clatworthy D, Ratnayake R, Klaesener-Metzner N, Roesch E, Wheeler E, et al. Understanding the menstrual hygiene management challenges facing displaced girls and women: findings from qualitative assessments in Myanmar and Lebanon. Confl Health. 2017;11:19. doi: 10.1186/s13031-017-0121-1 Epub 2017 Oct 20. PubMed PMID: 29046714; PubMed Central PMCID: PMCPMC5641996.
  • Sommer M, Utami D, Gruer C. Menstrual hygiene management considerations during Ebola response: a qualitative exploration. J Int Humanitarian Action. 2022;7:1–11. doi: 10.1186/s41018-022-00128-9
  • Muralidharan A, Patil H, Patnaik S. Unpacking the policy landscape for menstrual hygiene management: implications for school WASH programmes in India. Waterlines. 2015;34:79–91. doi: 10.3362/1756-3488.2015.008
  • Fry W, Njagi J, Houck F, Avni M, Krishna A. Improving women’s opportunities to succeed in the workplace: addressing workplace policies in support of menstrual health and hygiene in two Kenyan factories. Sustainability. 2022;14:4521. doi: 10.3390/su14084521
  • Caruso BA, Clasen TF, Hadley C, Yount KM, Haardorfer R, Rout M, et al. Understanding and defining sanitation insecurity: women’s gendered experiences of urination, defecation and menstruation in rural odisha, India. BMJ Glob Health. 2017;2:e000414. doi: 10.1136/bmjgh-2017-000414 Epub 2017 Oct 27. PubMed PMID: 29071131; PubMed Central PMCID: PMCPMC5640070.
  • Boyers M, Garikipati S, Biggane A, Douglas E, Hawkes N, Kiely C, et al. Period poverty: the perceptions and experiences of impoverished women living in an inner-city area of Northwest England. PLoS One. 2022;17:e0269341. doi: 10.1371/journal.pone.0269341 Epub 2022 Jul 15. PubMed PMID: 35834506; PubMed Central PMCID: PMCPMC9282460.
  • Hennegan J, Kibira SPS, Exum NG, Schwab KJ, Makumbi FE, Bukenya J. ‘I do what a woman should do’: a grounded theory study of women’s menstrual experiences at work in Mukono district, Uganda. BMJ Glob Health. 2020;5. doi: 10.1136/bmjgh-2020-003433 Epub 2020 Nov 22. PubMed PMID: 33219001; PubMed Central PMCID: PMCPMC7682193.
  • Singh V, Sivakami M. Normality, freedom, and distress: listening to the menopausal experiences of Indian women of Haryana. In: Bobel C, Winkler IT, Fahs B, Hasson KA, Kissling EA, Roberts TA, editors. The palgrave handbook of critical menstruation studies. Chapter 70. Singapore: Palgrave Macmillan; 2020. https://link.springer.com/book/10.1007/978-981-15-0614-7
  • Ballard AM, Hoover AT, Rodriguez AV, Caruso BA. Emphasizing choice and autonomy in personal hygiene, menstrual health, and sexual health product distribution to people experiencing homelessness in Atlanta, Georgia during COVID-19. Health Promot Pract. 2021;22:764–766. doi: 10.1177/15248399211024996 Epub 2021 Jul 8. PubMed PMID: 34229462.
  • Sommer M, Phillips-Howard PA, Gruer C, Schmitt ML, Nguyen AM, Berry A, et al. Menstrual product insecurity resulting from COVID-19 Related income loss, United States, 2020. Am J Public Health. 2022;112:675–684. doi: 10.2105/AJPH.2021.306674 Epub 2022 Mar 24. PubMed PMID: 35319956; PubMed Central PMCID: PMCPMC8961817.
  • Boden L, Wolski A, Rubin AS, Oliveira LP, Tyminski QP. Exploring the barriers and facilitators to menstrual hygiene management for women experiencing homelessness. J Occup Sci. 2021;30:1–16. doi: 10.1080/14427591.2021.1944897
  • Krusz E, Hall N, Barrington DJ, Creamer S, Anders W, King M, et al. Menstrual health and hygiene among indigenous Australian girls and women: barriers and opportunities. BMC Womens Health. 2019;19:146. doi: 10.1186/s12905-019-0846-7 Epub 2019 Nov 30. PubMed PMID: 31775735; PubMed Central PMCID: PMCPMC6882156.
  • Lowik AJ. “Just because I don’t bleed, doesn’t mean I don’t go through it”: expanding knowledge on trans and non-binary menstruators. Int J Transgend Health. 2021;22:113–125. doi: 10.1080/15532739.2020.1819507 Epub 2021 Sep 28. PubMed PMID: 34568874; PubMed Central PMCID: PMCPMC8040688.
  • Power R, Wiley K, Muhit M, Heanoy E, Karim T, Badawi N, et al. ‘Flower of the body’: menstrual experiences and needs of young adolescent women with cerebral palsy in Bangladesh, and their mothers providing menstrual support. BMC Womens Health. 2020;20:160. doi: 10.1186/s12905-020-01032-3 Epub 2020 Oct 1. PubMed PMID: 32738885; PubMed Central PMCID: PMCPMC7395369.
  • Spinhoven P, Zulaika G, Nyothach E, van Eijk AM, Obor D, Fwaya E, et al. Quality of life and well-being problems in secondary schoolgirls in Kenya: prevalence, associated characteristics, and course predictors. PLOS Glob Public Health. 2022;2:e0001338. doi: 10.1371/journal.pgph.0001338 Epub 2023 Mar 25. PubMed PMID: 36962912; PubMed Central PMCID: PMCPMC10022324.
  • Hennegan J, Nansubuga A, Smith C, Redshaw M, Akullo A, Schwab KJ. Measuring menstrual hygiene experience: development and validation of the menstrual practice needs scale (MPNS-36) in Soroti, Uganda. BMJ Open. 2020;10:e034461. doi: 10.1136/bmjopen-2019-034461 Epub 2020 Feb 20. PubMed PMID: 32071187; PubMed Central PMCID: PMCPMC7044919.
  • Hunter EC, Murray SM, Sultana F, Alam MU, Sarker S, Rahman M, et al. Development and validation of the self-efficacy in addressing menstrual needs scale (SAMNS-26) in Bangladeshi schools: a measure of girls’ menstrual care confidence. PLoS One. 2022;17:e0275736. doi: 10.1371/journal.pone.0275736 Epub 2022 Oct 7. PubMed PMID: 36201478; PubMed Central PMCID: PMCPMC9536616.
  • Hennegan J, Caruso BA, Zulaika G, Torondel B, Haver J, Phillips-Howard PA, et al. Indicators for national and global monitoring of girls’ menstrual health and hygiene: development of a priority shortlist. J Adolesc Health. 2023. doi: 10.1016/j.jadohealth.2023.07.017 Epub 2023 sep 22. PubMed PMID: 37737755.
  • Schmitt ML, Wood OR, Clatworthy D, Rashid SF, Sommer M. Innovative strategies for providing menstruation-supportive water, sanitation and hygiene (WASH) facilities: learning from refugee camps in Cox’s bazar, Bangladesh. Confl Health. 2021;15:10. doi: 10.1186/s13031-021-00346-9 Epub 2021 Feb 28. PubMed PMID: 33637096; PubMed Central PMCID: PMCPMC7912835.
  • Barrington DJ, Robinson HJ, Wilson E, Hennegan J. Experiences of menstruation in high income countries: a systematic review, qualitative evidence synthesis and comparison to low- and middle-income countries. PLoS One. 2021;16:e0255001. doi: 10.1371/journal.pone.0255001 Epub 2021 Jul 22. PubMed PMID: 34288971; PubMed Central PMCID: PMCPMC8294489.
  • van Eijk AM, Sivakami M, Thakkar MB, Bauman A, Laserson KF, Coates S, et al. Menstrual hygiene management among adolescent girls in India: a systematic review and meta-analysis. BMJ Open. 2016;6:e010290. doi: 10.1136/bmjopen-2015-010290 PubMed PMID: 26936906; PubMed Central PMCID: PMCPMC4785312.
  • Wilbur J, Torondel B, Hameed S, Mahon T, Kuper H. Systematic review of menstrual hygiene management requirements, its barriers and strategies for disabled people. PLoS One. 2019;14:e0210974. doi: 10.1371/journal.pone.0210974 Epub 2019 Feb 7. PubMed PMID: 30726254; PubMed Central PMCID: PMCPMC6365059.
  • VanLeeuwen C, Torondel B. Improving menstrual hygiene management in emergency contexts: literature review of current perspectives. Int J Womens Health. 2018;10:169–186. doi: 10.2147/IJWH.S135587 Epub 2018 Apr 26. PubMed PMID: 29692636; PubMed Central PMCID: PMCPMC5901152.
  • Hennegan J, Brooks DJ, Schwab KJ, Melendez-Torres GJ. Measurement in the study of menstrual health and hygiene: a systematic review and audit. PLoS One. 2020;15:e0232935. doi: 10.1371/journal.pone.0232935 Epub 2020 Jun 5. PubMed PMID: 32497117; PubMed Central PMCID: PMCPMC7272008.
  • van Eijk AM, Zulaika G, Lenchner M, Mason L, Sivakami M, Nyothach E, et al. Menstrual cup use, leakage, acceptability, safety, and availability: a systematic review and meta-analysis. Lancet Public Health. 2019;4:e376–e93. doi: 10.1016/S2468-2667(19)30111-2 Epub 2019 Jul 22. PubMed PMID: 31324419; PubMed Central PMCID: PMCPMC6669309.
  • van Eijk AM, Jayasinghe N, Zulaika G, Mason L, Sivakami M, Unger HW, et al. Exploring menstrual products: a systematic review and meta-analysis of reusable menstrual pads for public health internationally. PLoS One. 2021;16:e0257610. doi: 10.1371/journal.pone.0257610 Epub 2021 Sep 25. PubMed PMID: 34559839; PubMed Central PMCID: PMCPMC8462722.
  • Sumpter C, Torondel B. A systematic review of the health and social effects of menstrual hygiene management. PLoS One. 2013;8:e62004. doi: 10.1371/journal.pone.0062004 Epub 2013 May 3. PubMed PMID: 23637945; PubMed Central PMCID: PMC3637379.
  • Chandra-Mouli V, Patel SV. Mapping the knowledge and understanding of menarche, menstrual hygiene and menstrual health among adolescent girls in low- and middle-income countries. Reprod Health. 2017;14:30. doi: 10.1186/s12978-017-0293-6 Epub 2017 Mar 3. PubMed PMID: 28249610; PubMed Central PMCID: PMCPMC5333382.
  • Shannon AK, Melendez-Torres GJ, Hennegan J. How do women and girls experience menstrual health interventions in low- and middle-income countries? Insights from a systematic review and qualitative metasynthesis. Cult Health Sex. 2020;1–20. doi: 10.1080/13691058.2020.1718758 Epub 2020 Mar 3. PubMed PMID: 32116149.
  • GMMG. Priority list of indicators for girls Menstrual health and hygiene: technical guidance for national monitoring, global MHH monitoring group. New York: Columbia University; 2022. https://www.publichealth.columbia.edu/file/8002/download?token=AViwoc5e
  • Hennegan J, Winkler IT, Bobel C, Keiser D, Hampton J, Larsson G, et al. Menstrual health: a definition for policy, practice, and research. Sex Reprod Health Matters. 2021;29:1911618. doi: 10.1080/26410397.2021.1911618 Epub 2021 Apr 30. PubMed PMID: 33910492; PubMed Central PMCID: PMCPMC8098749.
  • Haver J, Long J, Caruso BA, Dreibelbis RD. New directions for assessing MHM in schools: a bottom-up approach to measuring program success. Stud Soc Justice. 2018;12:372–381. doi: 10.26522/ssj.v12i2.1947
  • Sommer M, Chandraratna S, Cavill S, Mahon T, Phillips-Howard P. Managing menstruation in the workplace: an overlooked issue in low- and middle-income countries. Int J Equity Health. 2016;15:86. doi: 10.1186/s12939-016-0379-8 PubMed PMID: 27268416; PubMed Central PMCID: PMCPMC4895811.
  • World Health Organization. Life course. Geneva: World Health Organization; 2021 [cited 2023 Aug]. Available from: https://www.who.int/our-work/life-course
  • de Francisco A, d’Arcangues C, Ringheim K, Liwander A, Peregoudov A, Faich H, et al. Perceived research priorities in sexual and reproductive health for low- and middle-income countries: results from a survey. Geneva: Global Forum for Health Research; 2009.
  • Rudan I, Gibson JL, Ameratunga S, El Arifeen S, Bhutta ZA, Black M, et al. Setting priorities in global child health research investments: guidelines for implementation of the CHNRI method. Croat Med J. 2008;49:720–733. doi: 10.3325/cmj.2008.49.720 Epub 2008 Dec 19. PubMed PMID: 19090596; PubMed Central PMCID: PMCPMC2621022.
  • Nagata JM, Ferguson BJ, Ross DA. Research priorities for eight areas of adolescent health in low- and middle-income countries. J Adolesc Health. 2016;59:50–60. doi: 10.1016/j.jadohealth.2016.03.016 Epub 2016 May 29. PubMed PMID: 27235375; PubMed Central PMCID: PMCPMC5357763.
  • Hindin MJ, Christiansen CS, Ferguson BJ. Setting research priorities for adolescent sexual and reproductive health in low- and middle-income countries. Bull World Health Organ. 2013;91:10–18. doi: 10.2471/BLT.12.107565 Epub 2013 Feb 12. PubMed PMID: 23397346; PubMed Central PMCID: PMCPMC3537249.
  • Ali M, Seuc A, Rahimi A, Festin M, Temmerman M. A global research agenda for family planning: results of an exercise for setting research priorities. Bull World Health Organ. 2014;92:93–98. doi: 10.2471/BLT.13.122242 Epub 2014 Mar 14. PubMed PMID: 24623902; PubMed Central PMCID: PMCPMC3949533.
  • Plesons M, Patkar A, Babb J, Balapitiya A, Carson F, Caruso BA, et al. The state of adolescent menstrual health in low- and middle-income countries and suggestions for future action and research. Reprod Health. 2021;18:31. doi: 10.1186/s12978-021-01082-2 Epub 2021 Feb 10. PubMed PMID: 33557877; PubMed Central PMCID: PMCPMC7869499.
  • USAID. Advancement of metrics for menstrual hygiene management in the workplace: final report. Washington DC: USAID Water, Sanitation, and Hygiene Partnerships and Learning for Sustainability (WASHPaLS) Project; 2021. https://pdf.usaid.gov/pdf_docs/PA00X8VB.pdf
  • WHO. Progress on household drinking water, sanitation, and hygiene 2000-2020: five years into the SDGs. Geneva: WHO, UNICEF; 2021. Available from: https://www.who.int/publications/i/item/9789240030848