FormalPara Key Points

Inadequate research, low menstrual health literacy, and lack of educational resources and training are barriers that prevent effective menstrual health monitoring for females, for both active individuals and elite athletes.

The development of educational resources that use correct terminology (in lay language) is required for athletes, coaches and support staff. This strategy could help improve appropriate and effective menstrual cycle health monitoring for females in sport and exercise environments.

A decision tree has been constructed for coaches, sporting organizations and athletes to inform decision-making on what menstrual health monitoring methods could be used, while also ensuring that there is some understanding/learning of what information will be provided.

1 Introduction

In 2023, the FIFA Women’s World Cup broke attendance records, drawing the largest crowds and ticket sales for a female-specific sporting event [1]. The year preceding this record-breaking World Cup event, the Tokyo Olympic Games demonstrated near parity in participation by male and female athletes, with Britain, Canada, China and Australia sending teams that were female-dominant [2]. However, the substantial growth in female sport participation has yet to be met with equality or equity in media coverage, salaries, athlete support (e.g., maternity leave, childcare support, mental and physical health), female leadership, female coaches, female-specific data and evidence-informed recommendations. As a result, in more recent times, an increase in sporting organization scrutiny by both athletes and media [3,4,5] has been observed. Organizations are criticized for their lack of female welfare and support, and subsequently calls to action have moved for improvements in policies and education from grassroots through to elite female athletes [5]. However, when turning to the research sector to inform education, performance and training recommendations, these organizations and individuals will find limited evidence [6].

To consolidate the available research on “How does the menstrual cycle affect exercise, sports performance, health, and well-being”, numerous audits of the available literature have been completed. These audits have investigated the extent of cis-female representation in the participant pool in sport medicine and exercise science journals [7], nutrition studies [8], research methodology [9, 10], menstrual cycle symptoms [11] and sport/exercise performance [12, 13]. Subsequently, these audits demonstrate how the issues of small sample sizes, the low quality in study design, and heterogeneity between studies and individuals have cumulatively contributed to a substantial cis-female data gap in sport and exercise science. As such, most sporting organizations have access to countless reviews that state that there is limited research evidence to inform adjustment of training, recovery or nutrition to the physiology of individuals who menstruate [8, 12, 13].

The data gap in cis-female research are also contributing to the consistent reports of low menstrual health literacy within sports [14]. Inadequate menstrual health literacy or menstrual health education will adversely influence the validity of the data provided by the individual on their menstrual health [15]. In addition, the reliability of menstrual health data may be questioned, especially when coaches and sporting organizations are faced with data-reporting compliance issues. For example, following the initial implementation of menstrual health data tracking, there may be high compliance by athletes due to its novelty. However, without coaches and support staff providing clear objectives on why data are being collected, there is a risk that once there is an increase in self-awareness or survey fatigue the consistency and reliability of data reporting may be reduced [15]. Of note, in the absence of athletes understanding why menstrual health data are being collected, the reporting of this health data may raise ethical concerns for athletes about how the data will be used by coaches and the organization [16]. Subsequently, counterarguments to the praise of menstrual health data collection and awareness within sports include misinterpretation of data, incorrect decisions on training, and performance, potential loss of privacy of the athlete, and disrespect for cultural sensitivities on the topic [16].

There is no argument that the menstrual cycle is a marker of female health. However, in the absence of high-quality research data, effective use of in-field data is likely to only occur once key issues pertaining to menstrual health literacy for athletes, coaches and support staff are addressed. Inadequate menstrual cycle and/or hormonal contraception knowledge of coaches has been suggested as a primary barrier to athlete communication, regardless of whether athletes rate their athlete-coach relationship favourably. Discussions with female coaches may occur more readily, but may still be limited to the coach’s education or influenced by the coach’s personal experiences/biases with their cycle. Exacerbated by the lack of formal education/discussions on the menstrual cycle and inadequacy of available research, any application of menstrual cycle tracking, monitoring or adjustment of training may be perceived as difficult, especially in the context of elite sports [17]. Therefore, education and resources that enable athletes, coaches and support staff to understand what they can monitor with regard to the menstrual cycle are required. This initial process may be beneficial to sporting organizations that wish to implement menstrual health discussions and health data collection in a culturally and ethically appropriate manner.

2 Basis for Resource Development

In the interim, standardizing menstrual health terminology and methodology by organizations, coaches and athletes should be considered a priority. Previously, academic experts in the field of sport and exercise have provided guidelines and a framework for current and future academics to consider when designing cis-female-specific in-lab research projects [10]. The provision of this framework has sought to remove the barriers that will enable high-quality research projects that are then able to provide evidence-based guidelines for female exercisers, their coaches, and support staff. Specifically, this work provided definitions of the female reproductive system and the diversity that may need to be considered throughout the lifespan both within and between cis-females. However, it is recognized that this paper was designed to improve research quality, and as such meets the needs of its primary target audience, academics and researchers in medicine, exercise and sport science. Therefore, the usability of this paper for applied, in-field support and education is limited.

Previous research acknowledges that even if menstrual health information is acquired by coaches, the complexity of the information remains a barrier to its usability (e.g., communication, understanding and awareness) [17]. Training management and physical performance are key considerations for coaches who desire a greater understanding of the physiological nuances that occur when working with female athletes [18]. To date, there is insufficient evidence available to suggest individualized training based on menstrual cycle phases or characteristics [13]. There may, however, be a consideration for individualized recovery and support provided to female exercisers/athletes that considers their unique physiology [18]. However, this may only be achieved with both coaches and athletes being aware and having transparent agreements on (1) what health data are being provided, (2) how these data may affect the discussions and management of the menstrual cycle, and (3) what data should be considered, collected and reported to ensure the individual’s privacy is maintained. As such, the following resource has been developed for cis-female athletes/exercisers, coaches and support staff to inform their decisions on menstrual health monitoring. The resource should enable any implemented health monitoring processes to remain in alignment with guidelines provided by academic experts in female-specific exercise and sport science.

3 Menstrual Health Manager (MHM)

To enable simple and informed decision-making on what menstrual health monitoring methods could be used, while also ensuring that there is some understanding/learning of what information will be provided, decision trees for menstrual cycle status have been developed (Figs. 1, 2, 3). Decision trees have been used in medical and healthcare settings to provide a support system that enables reliable and effective decisions to be made by practitioners [19, 20]. Decision trees provide a means of classification based on a series of questions on the features or characteristics associated with data [20]. The tree commences at the root node, and in this instance, the root node of ‘female’. The decision tree provides a series of questions, and each of these questions is contained within a node. In a simple binary format, each question of the decision tree has a simple yes or no response, with each possible answer directing the user to a specified child node [20].

Fig. 1
figure 1

A basic decision tree for determining menstrual cycle status. Commencing at the black root node ‘female’, simple binary questions (orange) can be completed to move progressively until a leaf (blue) node is reached. If responses to binary questions land on the green leaf node, then the individual using the resource should progress to Fig. 4. IUD intrauterine device

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Fig. 2
figure 2

An extension of Fig. 1 that can be used to determine the menstrual cycle status of a naturally menstruating female (black root node). Answering the menstrual cycle monitoring binary questions (orange) will progressively move the individual towards a leaf (blue), helping to establish the menstrual cycle status of the individual in each cycle. Detailed descriptions of each leaf (blue) are provided in Table 1. The menstrual cycle monitoring techniques and questions (orange) that are required to complete this decision tree are outlined in Table 2. Of note, ovulation in the decision tree has been stated as probable if a urinary ovulation test (LH surge) has been completed and is positive. To confirm ovulation a progesterone (P4) blood test will need to be completed 7–9 days after the urinary ovulation test. LH luteinizing hormone

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Fig. 3
figure 3

An overview of the continuum of female hormonal profiles, adapted from Allaway et al. [43], that correspond to each leaf in the naturally menstruating female decision trees (Figs. 1 and 2). After the individual has worked their way through the decision trees to identify the appropriate leaf and hence the menstrual cycle status of the individual, the assigned code on each leaf can be linked to the image and lay summary provided here or to a written description provided in Table 1. E1G urine metabolite of estrogen, estrone-3-glucuronide, PdG urine metabolite of progesterone, pregnanediol glucuronide, LH luteinizing hormone, FSH follicle-stimulating hormone

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Within this paper and the decision trees, the term ‘female’ was used to describe individuals designated with the biological sex characteristics that would enable menstruation to occur [21]. Historically, ‘female’ and ‘women’ post-puberty have both been used in the research literature to describe individuals who menstruate. However, it is acknowledged that the term ‘women’ may be used to describe the individual’s gender, with gender recognized as a social construct that depicts the roles and behaviors of individuals [21]. The decision tree has been designed for cis-gender females based on the presence of ovarian steroid concentrations. However, both sex and gender are not binary, and this may need to be considered when using this resource.

There are two outcomes when using the decision tree as a means of understanding what methods can be used to monitor menstrual health that athletes, coaches or support staff may consider. Firstly, users may select to work from the root node through a series of questions to a node that has no further questions, i.e. a leaf. To ensure adequate understanding and learning when using the resource, an expanded definition of each leaf of Figs. 1 and 2 is provided in Table 1, while a lay summary and image of the hormonal profile (endogenous estrogen and progesterone levels) associated with each leaf are provided in Fig. 3. For each leaf, a code has been provided to allow the user to find the appropriate menstrual cycle profile (Fig. 3) or description (Table 1). Users may then select to implement the in-depth menstrual health monitoring protocol that enables them to reach the relevant leaves. Details on what menstrual health monitoring tools or methods may be used to help respond to each of the binary questions within Fig. 2 are provided in Table 2. In Fig. 2, to ensure alignment with the recent IOC-REDs Clinical Assessment Tool [22], the suggestion of medical support to review the menstrual health status or required medical review of the identified menstrual health status has been provided.

Table 1 Leaf description, non-clinical and clinical definitions, and associated characteristics for naturally menstruating females
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Table 2 Menstrual cycle monitoring variables, their usability, and considerations for females
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Secondly, sporting organizations may use the decision trees to inform health monitoring processes. Thus, identify the amount of personal health data they may consider collecting, ensuring ethical and cultural sensitivities are respected. Specifically, it is acknowledged that there are ethnic and cultural differences in knowledge, practices and traditions concerning the menstrual cycle. The use of methodologies (e.g., blood sample collection, cervical mucus) that do not consider these diverse values of athletes could increase the risk of discrimination of individuals in an organization and result in inaccurate data due to the lack of engagement in implemented health monitoring [23]. In these instances, to ensure cultural safety is maintained, the users may work through the decision tree from the root node, selecting to stop at a more conservative node and not progress with any further questions to a leaf. Again, Table 2 may be used to help inform which menstrual health monitoring practices coaches and sporting organizations may use to inform health-specific decision-making with female athletes. For both circumstances, the author has provided the frequency with which menstrual health monitoring tools may be used to help inform decision-making and support provided to female athletes. These recommendations are based on the work previously completed by academic experts who have experience in female athlete health monitoring [24].

In recognition that not all premenopausal females may be naturally menstruating, a decision tree for hormonal contraception, a common hormonal milieu of active females [25,26,27], has been provided (Fig. 4). Hormonal contraception is defined as the provision of exogenous reproductive hormones that suppress endogenous reproductive hormone levels and may inhibit ovulation for the duration of time that the hormonal contraception is used [12]. The exception is the hormonal intrauterine device (IUD), where localized secretions of progestins have been shown to not inhibit ovulation throughout the duration of use [28].

Fig. 4
figure 4

Basic decision tree for hormonal contraceptive users. Commencing at a root node (black), binary questions (orange) can be completed until a leaf node is reached (blue). Details of each leaf node are provided in Table 3 and can be used collectively to provide education on the different types of hormonal contraception available to females. Details on menstrual health monitoring techniques for hormonal contraceptive users are provided in Table 2. OCP oral contraceptive pill, IUD intrauterine device

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Insights from research have suggested that the most utilized form of hormonal contraception is the combined oral contraceptive pill [25, 27, 29,30,31]; note, however, that there are many alternatives that females may have been prescribed [32,33,34], or have selected based on individual preferences. Due to different types, and brands, as well as the duration of exogenous hormone dose [12, 35], variations in exogenous hormone concentrations may occur. Therefore, while the choice of hormonal contraception remains that of the individual, support staff or coaches may use the flow chart to understand the various types that females may use and the methods by which they use these exogenous hormones (e.g., schedule). The flow chart is not provided as a tool to adjust or advise on hormonal contraception use: rather it is provided as an educational resource to inform athletes, support staff and coaches of the different types of hormonal contraception that an individual may use. This resource may be used to understand how hormonal contraception forms differ from each other and to naturally menstruating females. Additional details of each type of hormonal contraception are provided in Table 3. Finally, what health monitoring approaches may or may not be used for females who choose to use hormonal contraceptives have been provided in Table 2.

Table 3 Contraception type, exogenous hormones, and associated characteristics for females using hormonal contraceptives (see Fig. 4)
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The decision tree has primarily been made for cis-females who are classified as premenopausal, and future versions of the resource may incorporate decision trees for females at different life-cycle stages. However, in recognition of the various life-cycle stages that females may experience, Table 4 has highlighted some critical changes in female reproduction, detailing the basic physiological changes and subsequent presentations and considerations for health monitoring.

Table 4 Additional lifecycle phases of females, reproductive hormone characteristics, and considerations that influence health and exercise monitoring
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In recognition of common menstrual cycle disorders that females, both athletes and active individuals, may present with, Table 5 again defines the disorder and considerations for health, well-being and exercise/training monitoring. These definitions and considerations have been based on previous research on each of the conditions [36,37,38,39,40,41,42]. Details on health monitoring have been provided to support organizations or staff working with athletes at these various life-cycle stages or with a menstrual cycle disorder, providing a conservative framework to consider when implementing female health monitoring in sport and exercise. The resources are not diagnostic tools. Rather, if support staff or coaches identify common symptoms of disorders as a result of the menstrual health monitoring process, then it is advised that they seek out medical support and consultation.

Table 5 Common menstrual cycle disorders and considerations for health and exercise monitoring
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4 Conclusion

The decision trees and tables in this paper have been developed to educate and assist athletes, sports organizations and coaches with a framework that will enable them to develop or review their menstrual health monitoring methods. They are not suggested or intended as resources that can be used as diagnostic tools. It is anticipated these resources will help determine the details of menstrual health monitoring that may be implemented, while also ensuring that an improved understanding of the menstrual cycle occurs while still acknowledging the ethical and cultural perspectives of the individual/s providing the data. As such, these resources are likely to provide options for improved female health and well-being support and communication within a sporting environment that have previously been identified as barriers for coaches and support staff.