Introduction
Some decades back, the presence of women in athletics and sports was a rare phenomenon. After the 1970’s women started participating in all athletic sports. The huge increase in women participants in sports and especially athletics has contributed significantly to physical fitness and other health benefits. However, the increased physical activities of these athletes have led to a lot of physiological problems also. These physiological changes as a result of vigorous physical activity and stress have been a topic of study for many researchers from the late twentieth century onwards.
The core problems of elite female athletes have always been related to their reproductive system and its relation to the rest of the physiology. It is the dynamic rhythm of the reproductive system that differentiates the female gender from males. The cyclical changes in the hormone levels in the body of the females make their body prepared for pregnancy and childbirth. The starting of menarche is considered an important step in the growth and development of a female body. The major physiological problem with female athletes is the disorders affecting the menstruation cycle.
Lack of professional coaches causes misinformation about the requirement of nutritional diet and physical training. Increasing competition demands more physical strain which can contribute negatively to the physiology of female athletes. Increased physical activities including exercise and change in the diet which leads to change in the nutritional levels of the body, can affect the menstruation patterns of female athletes. The changes in menstruation patterns are the focus of study of many fitness researchers as they can affect the overall performance of the female body. Menstrual dysfunctions can cause other physical problems relating to bone mass and fat content of the body.
Research Question
What are the causes and consequences of irregular menstruation patterns in elite female athletes?
The purpose of this study is to investigate the prevalence of irregular menstruation patterns in elite female athletes and its consequences. A majority of female athletes are found to experience irregular menstruation patterns. Exercise and nutritional defects can be a reason for irregularity in menstruation in athletes. This can lead to menstrual disorders like amenorrhea, oligomenorrhea, and dysmenorrhea which may affect the Bone Mineral Content, Bone Mineral Density, and other physical and hormonal functions of the body. This paper researches the factors causing menstruation dysfunctions in athletes and the effect of menstrual disorders in sports performance. An investigation on the factors influencing menstruation patterns and menstrual disorders can provide more ground to the study in improving physical fitness in female athletes thereby causing improvement in sports performances. The study covers previous research papers conducted on the factors influencing menstrual patterns, menstrual disorders, and associated risks in women athletes.
Menstruation cycle and menstrual disorders
Ideally, the menses cycle of a normal healthy woman is 28 days long. However, only a very low number of normal women have their menstrual cycle recurring every 28 days. “The length of the menstrual cycle varies from woman to woman, cycle to cycle, year to year and decade to decade.” 2 A large number of studies have been conducted on female athletes and their menstruation patterns.
Annotated Bibliography
Holschen JC. The female athlete South Med J. 2004;97(9):852-858.
The article “the female athlete” by Holschen says that “The prepubertal female is equal in strength, aerobic power, heart size, and weight to her male counterpart. With the onset of puberty, the female body undergoes physiologic changes under the influence of the female sex hormones which affect bone mass, lean body mass, circulation, and metabolism.”1 The paper studies several physiological factors affecting the performance of female athletes.
The menstrual cycle and disorders related to it are stated as important factors influencing athletics and performing sports. The average age of menarche for most females is reported to be between 12 – 13 years. A delay of 1-2 years in menarche may be found in athletes who start their performance from a small age. Nearly half of the athletes are found to have irregular menstruation by Holschen. Jolie C Holschen is an MD at the Department of Orthopedic Surgery and Emergency Medicine, University of Michigan, and the article was a featured CME topic in sports medicine in the Southern Medical Association Journal. She is specialized in sports medicine and researches the role of hormones in injury and tissue repair.
Redman LM, Loucks AB. Menstrual disorders in athletes. Sports Med. 2005;35(9):747-755. Irregular menstruation or differences in bleeding patterns causes menstrual disorders in athletes. The definitions of menstrual disorders, incidences, and clinical consequences in athletes have been studied by Redman and Loucks, professors of the Department of Biological Sciences, Ohio University, and have been published in the Sports Medicine Journal.
Both Redman and Loucks have more than twenty years of professional experience and Prof Loucks is specialized in Reproductive endocrinology. According to it, the recurring menses cycle every 26-32 days in young and middle-aged women is considered to be normal and is termed eumenorrhea. A delay of more than 35 days in the menstrual cycle is referred to as oligomenorrhea and has negative effects on conceiving and may cause unintentional pregnancy.
Asymptotic sub-clinical menstrual disorders like Luteal Phase defects and Anovulation are caused by a decrease in luteinizing hormone pulse frequency and retarded follicular development respectively. Women having Luteal Phase defects and Anovulation are generally considered infertile. “The term ‘amenorrhoea’ denotes the persistent absence of menses.” 2 There are two types of Amenorrhea – primary amenorrhea is the delay in menarche beyond 15 years of age and secondary amenorrhea is the absence of menses after menarche.
Klentrou P, Plyley M. Onset of puberty, menstrual frequency, and body fat in elite rhythmic gymnasts compared with normal controls. Br J Sports Med. 2003;37(6):490-494.
Unlike normal women, females participating in athletic sports and performing arts like ballet, dances, etc undergo vigorous physical training. Women who participate in these sports tend to have delayed menarche and abnormal menses patterns. The prevalence of delay in menarche and menstrual frequency is studied by Plyley and Kentrou, Faculty of Applied Health Sciences, Brock University, Canada in their research paper published in the British Journal of Sports Medicine.
Prof Plyley was the president of, Sports Medicine and Science Council of Canada, and Dr. Klentrou has received the 2009 Chancellor’s Chair for Research Excellence Award, Brock University. They have doctoral degrees and a long list of research papers and publications to their credit. A total of 47 rhythmic gymnasts from Greece and Canada were taken as their subjects for study who had physical training for 23 – 24 hours a week and had started their training at an average age of 7 years. A control group of 78 non-athletes was also chosen who have regular menstruation. The onset of puberty is found to be delayed in most girls who start gymnastics training from a small age. “The time at which athletic training was initiated has been implicated as a factor in delayed menarche because intense training before puberty may alter hypothalamic-pituitary function.” 3
Also the amount of body fat and genetic factors are found to have an association with menarche. Gymnasts have a very small body and usually do not have enough Body Mass Index to get menses at the normal age of 12 – 13. “79% of the Greek and 34% of the Canadian gymnasts had not yet started to menstruate; the mean age of these groups was 14.5 and 14.7 years respectively.” 3 All the gymnasts in the study were found to have a BMI much lower than those from the control group.
“The intense physical training of those involved in rhythmic gymnastics is associated with delayed development of the normal menstrual pattern, with menarche being delayed by as much as 1.5–2.0 years.” 3 Secondary amenorrhea is found to be prevalent in such candidates. However, investigations on nutritional factors and environmental factors of the candidates were not taken into consideration in this study. A remarkable finding in the study is the difference in the BMI and body fat in Greek and Canadian control groups which suggest habitual differences as an influencing factor in menstrual patterns.
Warren MP, Stiehl AL. Exercise and female adolescents: effects on the reproductive and skeletal systems.
The effects of exercise on reproductive and skeletal systems were the topic of research by Dr. Warren, professor, and medical director, Department of Obstetrics and Gynecology at Columbia University College of Physicians and Surgeons, and Ms. Stiehl, research assistant, at the Center for Menopause, Hormonal Disorders, and Women’s Health at the Sloane Hospital for Women, Columbia-Presbyterian Medical Center in New York City.
Moderate exercise is proved to have benefits in the good balancing of the physique in females as it reduces adiposity and contributes to cardiovascular fitness and bone mass. Primary amenorrhea is found to be a negative effect of exercise. “While maternal age of menarche is the strongest correlate of the age of menarche, studies that controlled for genetic factors found that leanness is the best predictor of the age of menarche in athletes.” 4
Unlike studies shown by Plyley and Kentrou3, Warren and Stiehl have also stated that eating disorders and lack of a balanced diet cause menstrual dysfunctions. The influence of mental stress along with extensive physical training is also found to affect menstrual irregularities. Warren and Stiehl state that high-intensity physical training has effects on gonadotropin-releasing hormone (GnRH) pulse generator situated in the hypothalamus resulting in delayed menarche which is an extension of the study made by Plyley and Kentrou3. However, the effect of causal metabolic substrates on the hypothalamus is not identified.
Secondary amenorrhea and oligomenorrhea are found to have a close relationship with heavy exercise and weight loss. Athletes having low body fat, as less as 22%, are found to have secondary amenorrhea. “Irregular menses have been reported in 2% to 20% of casual runners, 50% of elite runners, and 30% to 50% of professional dancers. It is prevalent among women who experienced delayed menarche or previously irregular cycles, vegetarians, and athletes in sports where being underweight is advantageous.” 4 Poor nutrition in female athletes is also a cause for secondary amenorrhea. Warren and Stiehl suggest oral contraceptives and estrogen therapy for secondary amenorrhea and irregular menstruation patterns.
Dusek T. High-intensity training and menstrual cycle disorders in athletes. International SportMed Journal. 2004;5(1):37-44.
Seventy-two female athletes were interviewed to determine the prevalence of primary and secondary amenorrhea and dysmenorrhea to formulate a research paper on the influence of high intensive training on menstrual cycles of female athletes and were published in the Croatian Medical Journal by Dr. Dusek, MD, Department of Pharmacology Zagreb University School of Medicine, Croatia. 96 non-athletic girls compromised the control group. Computerized statistical calculation methods were used to analyze the prevalence of menstruation patterns and their dysfunctions in the study groups.
The results state that “Out of the 72 athletes, 6 had primary amenorrhea. Five of them did not start menstruating by the time of the survey. In contrast, not a single case of primary amenorrhea was recorded in the control group.” 5 20 athletes suffered from secondary amenorrhea while only 12 girls from the control group had secondary amenorrhea. Dusek’s study emphasizes the findings of Warren and Steihl4 and Plyley and Kentrou3 on the role of pre-pubertal physical training and lower volume of body fat in delaying menarche in female athletes.
Long-distance runners are found to have more cases of secondary amenorrhea than athletes involved in other sports. Lower body weight and lean structure is found as the reason for menstrual disorders in long-distance runners. However, intensive physical training involving stretching of muscles is found to alleviate muscle cramps associated with menstruation. The prevalence of dysmenorrhea is more in girls in the control group than in athletes. The paper lacks the study of body composition and its influence on menstrual patterns.
Bonis M, Loftin M, Speaker R, Kontos A. Body composition of elite, eumenorrheic and amenorrheic, adolescent cross-country runners. Pediatric Exercise Science. 2009;21(3):318-328.
The body composition of elite, eumenorrheic, and amenorrheic adult cross country runners was studied by Bonis, Loftin, Speaker, and Kontos and published in the Pediatric Exercise Science journal. Bonis and Speaker are faculty members at the College of Education and Human Development, University of New Orleans, and Bonis has research interests in bone development and growth response in adolescent athletes.
Loftin is the Chair and Professor of HESRM at the Dept. of Health Exercise Science and Parks and Recreation Management, University of Mississippi, and has a Ph.D. in Exercise Physiology. Kontos is with the Department of Kinesiology and Recreation Administration, Humboldt State University, Arcata. The purpose of the study was to investigate the influence of body composition in amenorrhea in runners. It was done by studying the composition of 28 young female cross country runners of which 17 were amenorrheic and 11 were amenorrheics. Literature reviews of several previous studies were cited in this paper suggesting the influence of high-intensity training on Bone Mineral Density and its influence in causing amenorrhea.
According to it “most female athletes meet these training demands without harm or incidence, some female athletes, especially those associated with weight-related or image-related sports, experience negative consequences, such as irregular menses or the complete cessation of menstrual function.” 6 The Bone Mass Density of both amenorrheic and amenorrheics athletes was measured using a dual-energy X-ray Absorptiometer (DXA) pre-season and post-season.
The pre-season statistics revealed a significant increase in Bone Mass Density in the eumenorrheic subgroup when compared to amenorrheics. There is no difference in height, weight, body fat, and lean tissue. However, the situation is a different post-season. “There were significant differences in BMD, body fat, bone mineral content, and bodyweight between the eumenorrheic and amenorrheic subgroups, with the eumenorrheic subgroup having significantly greater BMD, Body fat, Bone Mineral Content and bodyweight than the amenorrheic subgroup.” 6 The study made by Bonis et al. reveals that Bone Mass density, body fat, and bone mineral content influence menstruation patterns and menstrual dysfunctions, especially primary and secondary amenorrhea are more prevalent in athletes involved in weight-related or image and size-related sports.
Torstveit MK, Sundgot-Borgen J. Participation in leanness sports but not training volume is associated with menstrual dysfunction: a national survey of 1276 elite athletes and controls. Br J Sports Med. 2005;39(3):141-147.
Torstveit and Borgen, Department of Sports Medicine, Norwegian University of Sport and PE, Oslo, Norway propose that menstrual dysfunction is associated with participation in leanness sports and not training volume in their article published in the British Journal of Sports Medicine. Questionnaires involving inquiries in training and physical activities, diet patterns, eating disorders, and usage of oral contraceptives were given to 669 elite athletes and 607 non-athletes in the control group, both groups having representatives aged 13 – 39. Representatives younger than 16 years and the ones using oral contraceptives were excluded from analyzing the prevalence of menstrual disorders. Computerized statistical analyses of menstrual dysfunctions are provided as a graph.
“Percentage of athletes separated into leanness (n = 105) and non leanness sports (n = 229) and controls (n = 375) reporting present menstrual dysfunction (PMD).
PSA: Present Secondary Amenorrhea
Oligo: oligomenorrhea
SLF: short luteal phase
Each respondent could report more than one type of menstrual dysfunction but was only counted as one in the PMD group. Therefore, the percentage of secondary amenorrhea, oligomenorrhea, short luteal phase, and primary amenorrhea is more than 100%
*p<0.01 compared with non – leanness
tp<0.05 compared with controls.” 7
The results of this study state that athletes participating in leanness sports reported a higher prevalence of primary and secondary amenorrhea than the ones who are not involved in leanness sports and control group females.
The result of this report says that with age factors adjusted, the percentage of athletes and controls who reported menstrual disorders is the same. On the contrary, athletes competing exclusively in leanness sports have a higher prevalence of developing menstrual disorders than the ones participating in non-leanness sports and controls. The paper also investigates the prevalence of menstrual dysfunctions in athletes over the past decade and found that the prevalence of menstrual disorders has decreased in athletes over the years. However, the causes for the prevalence of irregularities in menstruation patterns are not discussed in this paper.
Egan E, Reilly T, Whyte G, Giacomoni M, Cable NT. Disorders of the menstrual cycle in elite female ice hockey players and figure skaters. Biol Rhythm Res. 2003;34(3):251-264.
In contrast to previous studies by Warren and Steihl4 and Plyley and Kentrou3 and Dusek5, the study on the disorders of the menstrual cycle in elite female ice hockey players and figure skaters by Egan et al. states that menarche is unrelated to pre-pubertal vigorous physical training and the age of commencing the sports career by the athlete in their article in the Biological Rhythm Research, the official journal of the European Society for Chronobiology.
However, the influence of maternal menarche age was emphasized to have a relationship with the age of menarche of the elite athletes. The researchers are Egan, Reilly, and Cable, Research Institute for Sport and Exercise Sciences at Liverpool John Moore’s University, Professor Greg Whyte Ph.D. FACSM is at present the Professor of Applied Sport and Exercise Science, Research Institute for Sport and Exercise Science, Liverpool John Moores University, and Giacomoni is from the Laboratoire Ergonomine Sportive et Performance, University of Toulon Var, France. Prof Cable is the director of the school and professor in exercise physiology.
The self-administered questionnaire was provided to 82 athletes comprising of ice hockey players and figure skaters. The results of the study are consistent with that made by Torstveit and Borgen7 on the influence of image-related sports activities on menstrual disorders. Egan et al.’s study on menstrual patterns in ice hockey players and figure skaters reveals that ice hockey players had more height and weight and greater Body Mass Index than figure skaters.
Also, the prevalence of amenorrhea and oligomenorrhea was more in figure skaters than in ice hockey players. In the study, the athletes were asked to consider the factors associated with menstrual disorders. “Fifty-two percent of the athletes who experienced menstrual dysfunction attributed their menstrual disorder to at least one training-related factor, 35% indicated some form of psychological stress, and 16% associated menstrual dysfunction with an eating or weight-related factor. In contrast, figure skaters were more likely to associate pressure from the competition, family friends and work or study and dietary factors with their menstrual dysfunction.”8
Thus, menstrual disorders are more related to the nature of the sport of the athlete. Athletes involved in sports that demand more physical strain and appearance and higher performance outcomes have a higher prevalence of primary and secondary amenorrhea and oligomenorrhea. The influence of body mass index, bone mass density, and body fat in menstruation patterns is found to be high as found in studies by Plyley and Kentrou3.
Wolman RL, Faulmann L, Clark P, Hesp R, Harries MG. Different training patterns and bone mineral density of the femoral shaft in elite, female athletes. Ann Rheum Dis. 1991;50(7):487-489.
Menstrual disorders have been found to have negative effects on the physical structure of female athletes especially in the bone mineral content and bone mineral density which are associated with the strength of the bones. Wolman, Faulmann, Clark, Hesp, and Harries belonging to the British Olympic Medical Centre, MRC Clinical Research Centre, and Northwick Park Hospital studied the different training patterns and menstrual status and their influence on the bone mineral density of the femoral shaft in female athletes.
The paper was published in the Annals of Rheumatic Diseases, an international peer-reviewed journal of the high standard covering all aspects of rheumatism. 67 elite female athletes involved in different sports and 13 eumenorrheic non-athletic women were studied and their bone mineral content was analyzed. Like previous studies on the subject, Wolman et al. failed to show the association of low estrogen levels and cortical bone in the femoral midshaft. “The study resulted that the mean bone mineral content in runners was significantly higher than in rowers, dancers, and sedentary controls.” 9Also amenorrhea was not found to influence Bone Mineral Content of the femoral shaft in athletes.
Kishali NF, Imamoglu O, Katkat D, Atan T, Akyol P. Effects of menstrual cycle on sports performance. Int J Neurosci. 2006;116(12):1549-1563.
Kishali, Imamoglu, Katkat, Atan, and Akyol from the Physical education and Sports High School of Ataturk and Mayis Universities, Turkey has published a paper on the effects of the menstrual cycle on sports performance involving a study of 241 athletes in ages varying from 19 – 22 years in the International Journal for Neuroscience. Menstrual disorders were found to increase in athletes during intensive exercise. Kishali et al. failed to find any negative effects of menstruation on sports performance and found that exercise decreased dysmenorrhea. “The number of athletes that felt good before and during the menstruation was significantly higher (p <. 05, p <. 01). Between menstruation periods, the athletes said that they felt better in the first 14 days than the second 14 days.” 10
Beals KA, Hill AK. The Prevalence of Disordered Eating, Menstrual Dysfunction, and Low Bone Mineral Density among US Collegiate Athletes. International Journal of Sports Nutrition & Exercise Metabolism. 2006;16(1):1-23.
The most significant problem associated with elite female athletes is the link between poor diet or eating disorders, menstrual disorders, and low bone mineral density. This is termed the Female Athletic Triad. The female athletic triad is seen as a serious problem in the sports world which can lead to osteoporosis and other bone-related diseases in adult female athletes. Low Bone Mass Density and Bone Mineral Content can cause fractures of the bones leading to permanent disability in these athletes.
This can cause them to end their athletic career. Several studies have been conducted on the prevalence and nature of the Female Athletic Triad. Research on the prevalence of disordered eating, Menstrual Dysfunctions, and low bone mineral density among athletes from the US was conducted and published by Beals and Hill in the International Journal of Sports Nutrition and Exercise Metabolism.
Beals is a faculty at the Division of Nutrition and Department of Family and Preventive Medicine, University of Utah, Salt Lake City, and Hill works with the Community Hospital of Indianapolis, Indianapolis. 112 collegiate athletes performing in seven different sports events divided into subgroups of leanness sports and nonleanness sports were the subjects of the study. The study revealed that the combined prevalence of all the three factors of the Female Athletic Triad is less in US athletes but individual disorders are prevalent. Eating disorders like “Bingeing « were reported by 23% of the athletes and 16% indicated that they regularly experienced “out of control eating.” 11
Menstrual dysfunction was reported in females having eating disorders and was more in athletes involved in leanness sports. The spinal Bone Mineral Density was correlated with the body mass and assessed in the athletes. It is found that the athletes participating in leanness sports had lower Bone Mineral Density when compared to the ones involved in non-leanness sports. This finding is in agreement with the findings of Torstveit and Borgen7 which state that athletes in leanness sports had higher health risks when compared to athletes of non-leanness sports and non-athletes.
Punpilai S, Sujitra T, Ouyporn T, Teraporn V, Sombut B. Menstrual status and bone mineral density among female athletes. Nurs Health Sci. 2005;7(4):259-265.
A comprehensive study on Menstruation patterns and Bone mineral density among elite female athletes was done by Punipilai Ph.D. Associate professor, Sujitra DNS, Assistant Professor, Ouyporn Ph.D., Instructor, Teraporn MD, Associate Professor, and Sombut MD, Associate Professor belonging to different departments of health studies at the Faculty of Medicine in the Chiang Mai University, Thailand. The paper was published in the Nursing and Health Sciences Journal.
Sixty-three Thai elite female athletes participated in the questionnaire asking for menstrual status, stress, dietary practices including calcium intake during six months. Blood samples, hormonal study, and Bone Mineral Density of the spine and femoral neck were determined. Discussions on previous studies on weight-bearing exercises by Punipilai et al. found that weight-bearing exercises improved the growth of pelvic bone and leg bones. But over-exertion can bring about menstrual dysfunctions and this is found to be a risk factor leading to decreasing in bone mass.
“The beneficial effect of physical activity in women on BMD can be lost if the amount of exercise is so intensive that it brings about menstrual disturbances.”12 In the study, the mean menarche age of the participating Thai athletes who started training at an early age was found to be 12.7 years and those who started training post menarche had it as 11.7 years. Almost 44% of these athletes are found to have menstrual dysfunctions. The study involved relation of menstrual status and Bone Mineral Density and “it was found that the menstrual status of the female athletes was significantly inversely correlated with the lumbar spine Bone Mineral Density but not with the femoral neck Bone Mineral Density.” 12
This is consistent with the findings of Holschen2 who reported that vigorous exercises can affect the secretion of estrogen thereby reducing its levels. Low estrogen levels will affect bone density and lead to osteoporosis and bone fractures.
Clinical Implications
The study on menstruation patterns of elite athletes, the factors influencing their menstrual cycle, and its consequences are matters of significance for athletes, their parents, and physical fitness trainers. The amount of physical activity can be determined to provide risk-free health and career to young athletes. Pre-pubertal girls must not be given excessive exercises to improve sports performance. Physicians and gynecologists can identify the underlying cause of low bone mineral density and the prevalence of osteoporosis in young female athletes and provide solutions. Nutritional plans should be made to overcome the unbalanced dietary practices of the athletes leading them to the risk of menstrual dysfunctions.
Elite female athletes can be given insights into the effects of menstrual disorders on their physical and skeletal health. This can help them understand the risks associated with leanness sports and seek professional help in exercise patterns and diet plans.
Conclusions
A majority of elite female athletes are found to have irregularities in the menstruation patterns and many suffer from primary and secondary amenorrhea, oligomenorrhea, and short luteal phase disorders. Genetic factors, over physical exertion in the pre-menarche age, and eating disorders have been found to cause primary amenorrhea or delayed menarche. Primary amenorrhea can lead to secondary amenorrhea in adult athletes. However, some studies showed that physical exercises are not associated with delayed menarche.
Athletes involved in image-related or size-related sports like skating, gymnastics, dance, etc had a higher prevalence of menstrual disorders than in those in nonleanness sports. Dysmenorrhea or muscle cramps associated with menses is found to be low in athletes than in non-athletes and is attributed to the continuous physical exercises of the athletes. Menstrual disorders can lead to skeletal-related disorders in female athletes causing osteoporosis and bone fracture. The prevalence of the Female Athletic Triad is also found in females in leanness sports.
Future Research
Though this paper discusses the menstruation patterns in elite athletes related to physical activity, several factors like smoking, genetic factors, habitual relations, and ethnicity of the female athletes are not considered in the research. Also, the amount of physical exercise needed for different age groups for the healthy well-being of the athletes has not been discussed. Future researches can give more implications to the influence of the nature of diet and habits in menstruation patterns. The associations of psychological status and menstrual patterns or their disorders are yet another field for future research.