The Prevalence and Impact of Heavy Menstrual Bleeding (Menorrhagia) in Elite and Non-Elite Athletes.

Heavy menstrual bleeding (HMB) is common, affecting a quarter of the female population.[ 1 ] HMB can negatively impact on physical, emotional and social quality of life and reduce work capacity.[ 2 , 3 ] Diagnosing HMB can be subjective and definitions include; blood loss of more than 80ml per menstrual cycle or “excessive menstrual blood loss which interferes with a woman’s physical, social, emotional and/or material quality of life”.[ 3 , 4 ] In a recent Europe-wide study a diagnosis of HMB was given if two or more of the following criteria were met; 1. passing of large blood clots, 2. need for double sanitary protection (both towels and tampons), 3. need for frequent changes of tampons and towels (meaning changes every 2 hours or less, or 12 sanitary items per period) and 4. flooding through to clothes or bedding.[ 1 ] The greater blood loss in HMB increases susceptibility to iron deficiency, which if left untreated may progress to iron deficiency anemia (IDA). Iron is an essential micronutrient required for numerous biological functions, including oxygen transport, cellular and mitochondrial respiration, electron transfer reactions, gene regulation, cell growth and differentiation.[ 5 ] Compromised iron stores cause adaptive changes, eventually resulting in limitations to the production of hemoglobin and a state of IDA. Menstruation is the most common single cause of IDA in females of a childbearing age,[ 6 ] with HMB specifically identified as the principal cause of iron deficiency and IDA in clinical practice in this population.[ 7 ] In a recent study of women with HMB, 63% of respondents reported being deficient in iron at some point.[ 1 ] However, despite the high prevalence of HMB, awareness is poor, with only a small minority (6%) of women seeking medical help annually.[ 8 ] The impact of compromised iron stores on oxidative metabolism in endurance athletes can be significant, potentially reducing total hemoglobin mass, oxygen carrying capacity and performance.[ 9 , 10 ] Furthermore, those who exercise are at higher risk of iron deficiency as a result of increased iron loss through hematuria (blood in urine), gastrointestinal bleeding, sweating and hemolysis (particularly exacerbated in impact sports involving foot strike).[ 11 – 14 ] Research into the impact of iron deficiency without anemia is inconclusive, with an identified need for further research.[ 15 ] While HMB has been shown to affect more than a quarter of women in the general population, the prevalence of HMB and the impact upon training and performance in exercising females has been unknown. We have recently published this headline data in a brief letter,[ 16 ] and in this paper we aim to 1. provide the full methods and results from this study, identifying the prevalence of HMB in exercising females; 2. determine any differential effect on exercisers of varying abilities; and 3. outline the perceived reported impact of HMB on training and performance which we were able to do through this research.

A total of 789 surveys were completed online. More than half (54.1%) of the participants had experienced HMB at some point ( Table 1 ).[ 16 ] 55.4% stated that their menstrual cycle impacts upon their training and performance ( Table 1 ), with those meeting the HMB criteria (n = 427) being more likely to state this (69.3% vs. 39.0%; χ2 = 867 . 593 , p<0 . 01) ( Table 2 ).[ 16 ] Those with a history of HMB were found to be older (31 years ±9.32 vs. 29 years ±7.49; H(2) = 10 . 392 , p<0 . 01) . [ 16 ] Significant differences between the values here from those meeting the HMB criteria and those who haven’t are shown as follows: *p < 0.001, **p < 0.01, ***p < 0.05. Of the 427 participants who met the HMB criteria, 37.2% had sought medical help for heavy periods ( Table 2 ). 1091 face-to-face surveys were collected and inputted into the Bristol Online Survey platform manually by the lead investigator and an assistant. Those with missing data or those completed by females who did not meet the inclusion criteria were excluded, resulting in a final sample size of 1073 for further analysis. Eight individuals declined to complete the survey once they had read the study information, and 61 declined answering the survey prior to being informed about the content typically citing a lack of time. Therefore, in stage 2, the survey was fully completed by 94% of randomly approached female marathon runners. The prevalence of HMB in females undertaking the 2015 London Marathon was 35.5% ( Table 1 ).[ 16 ] Overall nearly one third (31.7%) said that their menstrual cycle impacts upon their training and performance ( Table 1 ).[ 16 ] This was more than twice as likely to be a problem in those with HMB (48.3% vs. 22.5%; χ2 = 1151 . 481 , p<0 . 01 ; Table 2 ). Those who have experienced HMB were older than those who have not (35 years ±7.95 vs. 32 years ±7.83; H(2) = 18 . 936 , p<0 . 01) . Of the 381 participants who met the criteria for HMB, 44.6% had sought medical help ( Table 2 ). Across both groups, known anemia was reported by 603 (32.4%) participants, while 1049 (56.3%) specified that they were unsure whether they have had anemia.[ 16 ] Reported anemia was more common in those with HMB (40.7% vs. 26.0%; χ2 = 70 . 765 , p<0 . 01 ).[ 16 ] Use of iron supplementation was also more common in those reporting HMB (58.4% vs. 50.3%; χ2 = 39 . 199 , p<0 . 01) .[ 16 ] Less than a quarter of all surveyed reported having sought help for heavy periods (22.3%), with this increasing in those who met the HMB criteria (40.7%).[ 16 ] When a sub-analysis was conducted and elite athletes were separated out from both groups, 36.7% met the HMB criteria, with 51.1% indicating that their menstrual cycle has impacted upon their training and performance, with these being significantly related ( χ2 = 5 . 046 , p<0 . 05 ). A history of anemia was reported by 52.2%, with 78.9% having supplemented with iron ( Table 1 ). When participants who specified a 5km personal best time (n = 1166) were divided into groups based on the number of HMB symptoms they have experienced, a significant difference was found between groups ( H(4) = 11 . 464 , p<0 . 05 ), despite distributions looking similar. However, a post hoc analysis using pairwise statistics revealed no statistically significant pairwise comparisons. When simply comparing those with and without HMB, median 5km times were significantly different (25 minutes:0 seconds vs. 24 minutes:24 seconds; z = 3 . 099 , p<0 . 05 ). When 5km personal best times were divided into quartiles (Q1 being the fastest athletes), a significant difference was seen in HMB prevalence between groups (χ2 = 14 . 890 , p<0 . 01) , the faster runners in Q1 being less likely to have HMB (39.1%) than the slower runners in Q4 (53.1%) ( Fig 1 ). 5km personal best times (minutes:seconds) are divided into quartiles, Q1 representing those with the fastest times, Q4 the slowest. A significant difference was found between groups (p 0 . 05 ). Those exercising for >720 minutes each week appeared as likely to suffer from HMB as those exercising for 0 . 05) .

This study has demonstrated that HMB is common in the exercising population. HMB was associated with anemia, iron supplementation and slower performance times. Further research is however needed to explore the impact of HMB and iron deficiency on performance. The lack of medical help sought by the participants in this study suggests that either females don’t feel or realize this is a problem, or have learnt to cope with it, highlighting that more research and awareness is needed. HMB is also surprisingly common amongst elite athletes, ostensibly impacting upon their training and performance, and potentially causing iron deficiency, although further research is needed to confirm this association.

This research has been approved by the St Mary's University Ethics Committee. A 12-item ‘Female Health Questionnaire’ including free-text and yes-no polar questions was developed and designed to take 2–3 minutes to complete. The four-symptom definition of HMB [ 1 ] was used to identify HMB sufferers and information was collected on age, ‘personal best’ sports performance times, current training volume, previous history of anemia and iron supplementation (including as part of a multivitamin), the menstrual cycle and difficulties caused by it, and oral contraceptive pill (OCP) usage ( S1 Appendix ). The participants were informed that by indicating that they agree to the terms and completing the survey they have provided written informed consent for their information to be used in this study. The inclusion criteria were: female, aged ≥18 years, pre-menopausal and regularly exercising (≥90 minutes/week). The questionnaire was administered online and advertised through social media including Twitter, Facebook, online blogs and forums, university newsletters, websites and by word of mouth between 22 January 2015 and 19 May 2015. A link was provided to the internet-based survey in addition to some brief information about the research. Females registering for the 2015 London Marathon at the pre-event exhibition were surveyed using the same questionnaire. No bias was applied when selecting females to question and to avoid a response bias a scripted standardized introduction was made providing no specific information about the context of the survey. To ensure maximum response yield, surveys were completed at the time of asking. The questions and format of the paper copies used at the Exhibition were identical to the online survey to maintain equivalency and reliability of this mixed mode strategy.[ 17 ] Data were analyzed descriptively to summarize the prevalence of HMB, known anemia, iron supplementation, the seeking of medical help and impact of HMB on training and performance in both stages 1 and 2. The statistical analysis was completed using a predictive analytic software statistics computer package (IBM SPSS Statistics for Macintosh, Version 21.0, Armonk, NY: IBM Corp.). Statistical significance was set at P<0.05. Chi-squared tests were used to determine whether there was an association between HMB and presence of anemia and HMB and self-reported impacts on training and performance. Mann-Whitney U and Kruskal Wallis H tests were used to determine whether age and average weekly training volume were related to HMB. A Kruskal-Wallis H test with post hoc analysis and correction was used to determine whether 5km personal best time was linked to the number of HMB symptoms experienced, and Mann-Whitney U tests and Chi-squared tests were used to determine whether participant performance level (based on 5km personal best) was related to HMB incidence. After combining both groups, a sub-analysis was conducted to separate out elite athletes using the following criteria: 5km ≤18 minutes, 10km ≤36 minutes, half marathon ≤80 minutes, 2km row ≤7 minutes:45 seconds (elite running criteria defined using the 2015 ‘Great Run’ series definitions of ‘elite’, rowing criteria defined by English Institute of Sport physiologist). Participants were split into the following groups based on typical total minutes exercised per week 720 minutes.

The ‘Female Health Questionnaire’ that was completed either online or at the 2015 London Marathon Exhibition by all surveyed (n = 1862). (DOCX) Click here for additional data file. Letter to the Editor: The prevalence and impact of heavy menstrual bleeding amongst athletes and mass start runners of the 2015 London Marathon. (DOCX) Click here for additional data file.