Transgender individuals identify as a gender different than their sex designated at birth (1). The estimated prevalence of transgender individuals in the United States is 390 in 100,000 (2). Transgender athletes have made media headlines not only due to controversies of whether they should be competing as the traditional gender associated with their sex designated at birth or as the gender of their gender identity, but also after advocacy efforts have resulted in policy change for increased inclusion in sport (3). This article aims to review the literature relevant to the care of transgender athletes. This includes terminology, epidemiology, policy, and medical considerations. Relevant articles are cited, which in some cases include articles more than a couple of years old. We feel it is important to include these older articles in addition to the newer material, especially given the paucity of literature in the area.
Relevant terminology is reviewed in detail in Table 1 (1,4–7). As with any population, preferred terminology is constantly changing and may vary in different cultures or social settings. Individuals have the right to their own preferences on terminology use, so it is of utmost importance for clinicians to ask patients and athletes their preferences to provide the most comfortable environment for them. If unsure about the individual’s pronoun preferences, it is best to simply ask. The web site www.mypronouns.org is a good reference for additional information on pronoun use (7).
Epidemiology of the Transgender Athlete
Research suggests that there are decreased levels of physical activity and sports participation in transgender individuals when compared with cisgender individuals (8–10). A recent systematic review revealed that poor access to inclusive environments was the primary reason for lack of sports participation among transgender athletes. The review also showed that many transgender athletes had negative experiences with competitive sports due to the restrictive nature of the policies surrounding their participation (11). It also is important to consider that medical interventions related to gender affirmation, such as hormone therapy and/or surgery, are timely and may conflict with training time for sport. Particularly, individuals undergoing surgery require recovery time that will significantly conflict with training for elite athletics. Some sport policies also require a waiting time after surgery or the initiation of hormone therapy before participation as the gender to which the individual is transitioning. This can decrease the time that the individual is able to participate in their sport. Some individuals may even delay medical or surgical interventions for gender affirmation until they have completed their sports career or important competitions to avoid these delays in training or competition.
Certainly, not all transgender individuals choose medical and/or surgical means of gender affirmation, but for those who do, typical treatments are described in this section.
Hormone therapy for transgender males involves treatment with testosterone (4,5). With this treatment, menses often stops within a few months. If this is not the case, other treatment can be considered, such as use of a progestational agent or endometrial ablation. For some, gonadotropin-releasing hormone (GnRH) analogs or depot medroxyprogesterone can be used before testosterone therapy to result in decreased estrogen and cessation of menses (4).
Transgender females who undergo hormone therapy are typically treated with an antiandrogen and estrogen therapy (4,5). Spironolactone is an oral antiandrogen commonly used in the United States (1). Cyproterone acetate is an oral antiandrogen that is commonly used in Europe, but is not currently approved in the United States (4). Among estrogens, thromboembolic risks are highest with the ethinyl estradiol; therefore, its use is advised against in the 2017 clinical practice guideline: “Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline” (4).
While the above is a general overview of common strategies of hormone therapy in the transgender population, it is important to note that complexities, such as hormone regulation before and after gonadectomy, also are taken into account. Hormone levels also are routinely monitored by the clinician managing the individual’s hormone therapy to ensure appropriateness of the regimen (4,5). For elite athletes, a therapeutic use exemption (TUE) needs to be submitted before competition for medications on the prohibited list, such as spironolactone and testosterone (12).
Gender Affirmation Surgery
Transgender males who wish to undergo gender affirmation surgery can undergo various procedures. These include “top surgeries”: mastectomy and chest wall reconstruction and “bottom surgeries”: hysterectomy, salpingooophorectomy, vaginectomy, urethroplasty, metoidioplasty, phalloplasty, and/or either scrotoplasty or testicular prosthetic insertion, in addition to hormone therapy (5,13). Transgender males more commonly opt for “top surgery” than “bottom surgery.” This may be related to the distress associated with having female contours with a male gender identity (4).
Transgender females who wish to undergo gender affirmation surgery can undergo “top surgery”: breast augmentation and/or “bottom surgeries”: penectomy, clitoroplasty, labiaplasty, orchidectomy, and/or vaginoplasty, in addition to hormone therapy. Additionally, some transgender females may choose to have facial feminization surgery, hair removal, and/or shaving down of the tracheal cartilage (5,13).
Other Physical Means of Gender Affirmation
Transgender males who have not undergone “top surgery” may perform the practice of binding, which is the use of tight garments (shirts or sports bras) or bandages to create a flat contour of the chest. Transgender males who have not undergone “bottom surgery” may perform the practice of packing, which involves the use of a penile prosthetic in their undergarments to create a male contour (1).
Transgender females who have not had “top surgery” may opt for soft tissue fillers that are not standard of care. These fillers, such as silicone, aim to create a female chest contour, but can have complications, such as skin reaction, necrosis, or silicone embolization, which could result in death, so this practice is discouraged (1).
Transgender females who have not had “bottom surgery” may perform the practice of tucking to demonstrate an external appearance of a smooth contour for the purpose of gender affirmation. Tucking involves posteriorly pushing the penis and scrotum into the perineal area and pushing the testicles, when present, into the inguinal canal. Tight-fitting underwear, a specialized undergarment known as a gaffe, or tape, can help to maintain the tucking position (1).
In October 2003, the International Olympic Committee (IOC) Medical Commission had an ad hoc committee meeting in Stockholm to create a policy for inclusion of transgender athletes in the Olympic Games (14). This policy, released in May 2004 and referred to as the Stockholm Consensus, allowed for transgender females who had transitioned before puberty to compete in the female gender category and transgender males who had transitioned before puberty to compete in the male gender category (3,14). Transgender males and transgender females who transitioned after puberty were allowed to participate as their gender identity under more strict criteria. These criteria required surgery (external genitalia surgery and gonadectomy), legally documented recognition of their gender identity, and hormone therapy (which had to have been administered in a way that was verifiable and for a long enough period suitable to the committee). Of note, it was recommended for gonadectomy to be performed at least 2 years before competition (14). There were mixed opinions about this policy after it was released, as some had concerns that individuals were going to change genders simply to have an athletic advantage and others arguing that the details of the policy were too restrictive and not evidence-based (3,11).
Since that time, the IOC has updated its policy to a less restrictive one, which no longer requires gender affirmation surgery or legal recognition of the athlete’s gender (11). The new 2015 policy states that transgender males may compete in the male category. Transgender females who have declared their identity as female (which cannot be changed in relation to sport for 4 years after proclamation) and who have serum testosterone levels less than 10 nmol·L−1 for 12 months leading up to competition and throughout the period of competition eligibility are able to compete in the female category. It is noted that testing may be performed to confirm compliance and that if an athlete does not meet the criteria, she would not be able to compete in the female category for at least 12 months (15).
Many other sports organizations have policies regarding participation of transgender athletes in their organizations. Sports policies vary in their requirements to participate as a male or female gender. Many policies have followed the original, and more restrictive, Stockholm Consensus guidelines and have not been updated to reflect the newer IOC guidelines, while others are more inclusive (11). The web site https://www.transathlete.com/, created by transgender male athlete Chris Mosier, includes up-to-date information on the policies of various sports organizations throughout the world (16). Table 2 reviews a selection of current policies at the time of the preparation of this article in July 2018 (12,15–18).
Of note, Handelsman et al. (19) reported in 2018 that testosterone level has a direct impact on athletic level and recommended the use of 5 nmol·L−1 as the upper limit of testosterone for participation in female athletics, which may result in policy changes among sporting organizations.
Transgender Athletes in the News
Transgender athletes have made headlines in recent years, mostly not only due to controversies over participation but also because of successful advocacy efforts, and of course, athletic successes.
Controversies regarding transgender athletes’ sports participation often stem from a concern about unfair advantage, particularly for transgender females. One such case is the case of Kristen Worley, a transgender female cyclist from Canada who reached a settlement with Cycling Canada, Ontario Cycling Association, and the Union Cycliste Internationale (UCI) in 2017 after her claim that their hormone range restrictions prevented her from participating in her sport at an elite level (20). The settlement resulted in these organizations reassessing their policies for better inclusion and advocating for evidence-based guidelines for transgender athletes (21,22).
Transgender male athletes also have made headlines. Chris Mosier is a transgender male duathlon athlete who advocated for a change to the IOC policy for participation of transgender athletes, helping to inspire the 2015 changes. He became the first known transgender member of a men’s US National team (23–25). A more recent case is the 2018 case of Mack Beggs, a transgender male. Mack is a high school aged competitive wrestler in Texas who wished to participate as male, consistent with his gender identity, but due to the policy of the Texas high school athletic association, the University Interscholastic League (UIL), he has been required to compete in the female category, as this was his sex designated at birth. In this case, there is concern that when competing as a female, Mack may have an unfair advantage over cisgender females due to his testosterone therapy; however, participation in the female category is mandated by the UIL and not Mack’s preference (26).
These cases help to highlight the importance of advocacy and literature in this population to help guide evidenced-based policy for inclusion in sports.
Below are medical considerations when caring for transgender athletes. A number of comprehensive care guidelines regarding medical care of transgender individuals exist (as referenced at the end of this sentence) and are useful references for a more thorough discussion of the following considerations (1,4,6,27).
Research has shown that before hormone therapy, transgender females have lower baseline bone mineral density when compared with transgender men or age-matched males, respectively (28). In a study involving transgender females and males, 23% of the 47 transgender women on hormone therapy had bone mineral density findings of osteoporosis at the lumbar spine, 9% at the femoral neck, 2% at the total hip, and 26% at the left radius (29). Transgender men did not have bone mineral density findings consistent with osteoporosis (29). A study comparing transgender females to age-matched control cisgender males demonstrated that before hormone therapy, transgender females have lower muscle mass, strength, and bone mineral density than age-matched males. This is thought to be due to the aforementioned decreased physical activity in this population compared to the general population (28). A prospective study of bone health in transgender women from this same group showed that although fat mass increased and muscle mass and strength decreased, bone mineral density was maintained or even slightly increased after hormone therapy (9). A similar prospective study of bone health in transgender men showed that muscle mass increased, fat mass decreased, and trabecular bone mineral density at the distal radius and total hip increased after hormone therapy (30). A systematic review of the literature on bone health in transgender individuals concluded that while there was a small increase in bone mineral density at the lumbar spine of transgender women receiving hormone therapy, there was no evidence for significant bone mineral density changes in transgender men receiving hormone therapy (31). It is thought that individuals who cease hormone therapy after gonadectomy may be at a higher risk of bone loss/low bone mineral density. Because of this, clinical guidelines recommend evaluating bone mineral density in transgender individuals who stop hormone therapy after gonadectomy and those with other risk factors for low bone mineral density (4).
While differences in injury patterns between cisgender female and male athletes have been studied, we were unable to find any studies specifically evaluating musculoskeletal injury patterns among transgender female or male athletes.
Starting at puberty, cisgender females have an increased risk of noncontact anterior cruciate ligament (ACL) tears compared to males (32–34). Puberty is when neuromechanical factors are thought to diverge in cisgender athletes, with cisgender female landing mechanics becoming riskier for ACL injuries compared to the landing mechanics of cisgender males. These factors seen in postpubertal cisgender females are divided into four commonly described neuromuscular imbalances: 1) ligament dominance (landing in a way that puts more force and stress on the ACL compared to use of the lower extremity musculature; this can be seen with increased dynamic knee abduction during landing), 2) quadriceps dominance (higher recruitment of the quadriceps compared with the hamstrings), 3) leg dominance (asymmetries seen side to side with leg strength and/or neuromuscular control), and 4) trunk control (increased lateral displacement of the trunk during landing) (35). The divergence of neuromuscular patterns into male and female patterns after puberty suggests that sex hormones may have an impact on these patterns. Although not specifically examining the effects of hormone therapy on ligamentous stiffness in transgender individuals, there has been research evaluating hormonal influences at ligaments in cisgender individuals. Studies have shown that ACL injuries are more likely to occur in women during the preovulatory menstrual phase, suggesting hormonal influence at the ACL (36–39). Increased levels of estrogen have been correlated with decreased levels of ACL stiffness (39,40). Studies examining the effects of oral contraceptive pills on ligamentous laxity have been mixed, with some showing decreased ligamentous changes with the use of oral contraceptive agents and others showing no differences (36,38,39,41–43). Future research is necessary to better determine the effect of sex hormones on the ligaments of cisgender and transgender women and men.
Although little research exists in the area of postsurgical musculoskeletal concerns in transgender athletes, it is important for the sports medicine physician to consider the postoperative status of the transgender athlete who has undergone gender affirmation surgery when evaluating musculoskeletal chief complaints in the regions of the chest wall or pelvis. For instance, the sports medicine physician or other provider should question if hip/pelvic pain could be associated with postoperative pelvic floor dysfunction. Chest tightness and/or shoulder stiffness are known risks of mastectomy (44). The sports medicine physician or other provider evaluating chest, shoulder, or neck concerns in a transgender male athlete after mastectomy should consider this complication as a possible contributing factor when determining an appropriate differential diagnosis. These are just some of many likely examples of possible postoperative considerations sports medicine physicians should address, and this is certainly a much-needed area of research to help improve evidence-based care of the transgender athlete.
Of note, appropriate equipment for prevention of injury should be considered based on each individual’s anatomy. For example, transgender females who have male genitalia should still wear a cup for testicular protection while participating in contact sports.
There is a need for research in the areas of musculoskeletal injury patterns and injury prevention strategies in transgender athletes to improve evidence-based care for this population.
Thromboembolism and Cardiovascular Risk
Estrogen therapy is a known risk factor for thromboembolism and has been described in transgender women receiving hormone therapy (29,45,46). A recent systematic review of the literature concluded that while the risk is present, hormone therapy can be safely administered with ways to decrease the risk of venous thromboembolism through avoidance of the use of ethinyl estradiol, which has been associated with an increased risk of venous thromboembolism, and preferential use of transdermal estrogen, which decreases this risk by avoidance of hepatic first pass metabolism (29,45–52). The risk of thromboembolism is clear; therefore, it is important to limit the risk through the use of transdermal treatment when possible, through screening transgender women on hormone therapy for this complication, and by counseling patients on signs and symptoms and other modifiable risk factors.
Testosterone therapy may lower low-density lipoprotein values and elevate high-density lipoprotein and triglyceride levels (4). A systematic literature review concluded that there is not enough evidence to fully determine cardiovascular and thromboembolic risk in transgender males on hormone therapy. Likewise, there have been mixed reports of the effects of hormone therapy on cardiovascular risk factors in transgender females, suggesting the need for more research into this area for both transgender females and transgender males (4,53). Transgender individuals should have routine monitoring of lipid panels and other cardiac screening based on risk factors and general public health guidelines (4).
Although there has been some concern about cancer risk in this population, a 2015 systematic review of the safety of hormone therapy in transgender adults by Weinand et al. concluded that there is no evidence to support any increased risk of cancer from hormone therapy (45,54–56). While not federal guidelines, there are a number of guidelines that discuss recommendations for routine cancer screening for transgender individuals, as can be seen in the following cited references (1,4,27).
Although more data is required before reaching more conclusive evidence, there are reports of possible increased insulin resistance and fasting glucose in transgender individuals on hormone therapy (45,54,57). Current clinical guidelines suggest routine screening in this population (1,4). Treatment with estrogen therapy may increase the risk of prolactinomas, although the risk is thought to be low. Current clinical guidelines recommend routine prolactin level monitoring (4).
In addition to gender dysphoria, discussed earlier, there are other mental health comorbidities in this population. A recent systematic review of the literature revealed that mental health conditions such as depression, anxiety, suicidality, and substance use disorders are comorbid concerns in this population (58). In a 2018 study of transgender high school aged youth, 33% reported non-suicidal self-harm and 18% reported non-suicidal self-harm and suicide attempts within the past year. Being a victim of bullying, physical, or sexual abuse increased the risk of self-harm (59).
A large study by Diemer et al. (60) in 2015 demonstrated a higher rate of self-reported eating disorders, vomiting, use of diet pills, and use of laxatives among transgender college students compared with their cisgender counterparts. These patterns also have been shown through a smaller study by Guss et al. (61) and a case series by Donaldson et al. (62). Another large study, published in 2017, showed similar results, with high rates of binge eating or fasting or vomiting for weight loss. This study also examined factors associated with and protective against these behaviors, determining that stigma was associated with an increased risk of eating disorder behaviors and social support was associated with decreased risk of eating disorder behaviors (63). Donaldson et al. (62) highlights the importance of addressing eating disorders in this population with a multidisciplinary team and an emphasis on mental health, family therapy, and treatment of any feelings of gender dysphoria.
It is important to screen for mental health needs, to advocate for antibullying programs, and to help create an inclusive environment as stressors and stigmatization can lead to mental health concerns in this or any population (6).
Tucking can lead to genitourinary complications, such as hernia, urinary reflux, prostatism, epididymo-orchitis, prostatis, or cystitis (1). Transgender females may experience genital pain when starting hormone therapy. The cause of this is still unclear. Scrotal pain should be clinically worked up to rule out emergency or serious conditions such as hernia, hydrocele, or tumor. At times, this requires ultrasound imaging in addition to history and physical examination (1,64,65). Genital examination in transgender women can be a traumatic experience. The clinician should be sensitive to this to provide the most compassionate care (1). The treatment of pain is dictated by the diagnosis. If thought to be secondary to tucking, counseling can be provided on modifications to this technique, such as tucking less tightly or for shorter lengths of time. Chronic scrotal pain with a negative work-up may be treated with empiric antibiotics, neuropathic pain medications, or orchiectomy. While orchiectomy is considered a last resort approach in cisgender males, it should be considered earlier in transgender females as not only can it be helpful to relieve scrotal pain, but it also can be gender affirming (1).
Pelvic pain in transgender males can be secondary to atrophic vaginitis, cervicitis, or dyspareunia (due to testosterone hormone therapy use), posttestosterone cramping (seen with hormone therapy but of unclear pathophysiology), infectious vaginitis or cervicitis, urinary tract infection or cystitis, gynecological conditions such as pelvic inflammatory disease or ovarian (when present) complications such as ovarian torsion, sexually transmitted infections (STIs), pregnancy, sequelae of sexual trauma, postsurgical pain or complications such as adhesions or scar tissue, musculoskeletal pain such as that caused by muscular changes from testosterone treatment, strains or imbalances of hip girdle musculature, or pelvic floor dysfunction, or neurogenic pain, such from sources such as the nearby pudendal nerve (1,66). A comprehensive work-up should occur to help determine the cause of pelvic pain, with care to screen for possible comorbid mental health conditions, such as posttraumatic stress disorder and/or depression (1). Treatment should be targeted based on the diagnosis and should include appropriate pain management in addition to targeted treatments (i.e., pelvic floor physical therapy for pelvic floor dysfunction or vaginal estrogen for atrophic vaginitis; etc.) (1). If the pain seems to be cyclical in correlation with a cyclic testosterone regimen, transdermal testosterone with a more consistent delivery may be helpful. The addition of a progestogen to the regimen, such as a levonorgesterel intrauterine device (IUD) also has been suggested (1). These adjustments should be made by or with consultation of the clinician primarily managing the patient’s hormone therapy. Depending on the pelvic pain diagnosis and future fertility goals of the patient, in some cases, hysterectomy and/or oophorectomy may be considered as part of the treatment plan (1).
During reproductive years, transgender men who have not undergone “bottom surgery” and who are not on hormone therapy with testosterone experience menstrual periods. For transgender men being treated with hormone therapy, menstrual periods typically cease after 6 months of testosterone treatment. Unexpected vaginal bleeding outside of that described above requires further evaluation for conditions such as pregnancy, endometrial hyperplasia or polyps, adenomyosis, leiomyomata, malignancy, hematologic conditions, ovulatory dysfunction, or other endometrial or iatrogenic causes (1,67). Treatment should be guided by diagnosis (1).
Binding or tucking can cause skin irritation, fungal infections, or local pain. Adjustments in technique and appropriate skin care or treatments can help to alleviate symptoms (1).
It is critical for the sports team and sports medical team to create an inclusive environment. Educating the sports team, athletics staff, and sports medical staff about terminology and pronouns is a great first step. Medical staff also should be educated about medical considerations in this population. Restrooms should promote gender inclusion by either being gender neutral or making it clear that female restrooms are for all individuals who identify as female, and likewise all male restrooms are for individuals who identify as male. As described in Deustch’s “Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People,” if separate female and male gender restrooms are provided, it is best to also have a gender-neutral restroom for individuals who identify as nonbinary or those who are undergoing the transition process of gender affirmation. Chosen name, pronouns, and gender identity should be kept up-to-date and saved in an easily accessible part of the athletics records and medical records. Inclusive posters, pins, shirts, and/or flags help to show transgender and nonbinary individuals that they are safe and supported in their environment. Every individual is different about what they feel comfortable sharing about their gender identity, so it is crucial to emphasize privacy and confidentiality in the sports and sports medicine setting (1,6).
Although the sports world has become more inclusive toward transgender athletes, there is still more work to be done in this area. Transgender individuals have been shown to have decreased rates of physical activity and sports participation compared to cisgender individuals, which may be, in part, due to stigmatization and lack of inclusion. While sporting organizations have created policies geared toward inclusion, some of these policies are restrictive, leaving some competitors “out of the game”. While the literature has become more abundant on the care of transgender individuals, there is still a need for more literature on the care of the transgender athlete and on musculoskeletal considerations for transgender individuals.
The authors declare no conflict of interest and do not have any financial disclosures.
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