Causes of Abnormal Menstruation: Sports-Related Concussion and Non-Head Injuries

Researchers examined menstrual patterns in 128 patients with either a sports-associated concussion or non-head injury.

Compared with sports-associated, non-head orthopedic injury, a sports-associated concussion is more likely to result in abnormal menstruation and irregular bleeding, according to data published in JAMA Pediatrics.

Anthony P. Kontos, PhD, of the department of orthopedic surgery at the University of Pittsburgh Medical Center Sports Medicine Concussion Program in Pennsylvania, and colleagues, conducted a prospective cohort study of 128 young women who presented to the University of Pittsburgh Medical Center Sports Concussion Clinic or Center for Sports Medicine with either a sports-related concussion or a non-head, sports-related orthopedic injury. Dr Kontos and colleagues aimed to compare menstrual patterns in both populations.

The primary study outcome was abnormal menstruation (intermenstrual interval <21 or >35 days or a bleeding duration of <3 or >7 days).

Following clinical confirmation of concussion, study participants (mean age: 15.7±1.8 and 16.6±2.0 in the concussion vs non-head injury groups, respectively) received weekly automated text messages with an online survey link, which asked participants questions on the following topics related to their menstrual experiences:

  • did you experience any bleeding episodes, and if so, the day the bleeding began and the duration
  • did you experience any new injury for which medical attention was received, and if so, classify the injury type
  • did you start or continue to use any hormonal contraception
  • are you or could you be pregnant

Weekly text messages were sent until 120 days post-injury, capturing data from 3 to 4 menstrual cycles. Survey response rate was 94.5% (1784 responses to 1888 text messages received); 487 bleeding patterns were recorded for 128 patients.

In total, 2 to 6 bleeding patterns were reported following injury, with 44.5% of patients reporting at least 1 abnormal bleeding pattern. In the concussion group, 23.5% of participants experienced 2 or more abnormal bleeding patterns (vs 5% of patients in the non-head injury group). Participants with concussions were at an increased risk of experiencing two or more abnormal menstrual bleeding patterns (odds ratio [OR]: 5.58; 95% CI, 1.61-21.22), and had a significantly increased risk of experiencing short intermenstrual intervals vs participants with a non-head injury (OR: 5.60; 95% CI, 1.19-26.38).

“[P]resent findings suggest that more subtle forms of brain injury, such as concussion, may adversely affect [hypothalamic-pituitary-ovarian] axis function…through a number of proposed mechanisms leading to disrupted gonadotropin secretion,” wrote Dr Kontos and colleagues.

The researchers stress that clinicians treating patients with concussion should “inquire about menstrual patterns to identify those patients who may develop abnormal menses,” which would result in appropriate evaluation and improved health outcomes.

“Larger studies with hormonal assessments and long-term follow-up are needed to better understand the effect of concussion on the HPO [hypothalamic-pituitary-gonadal] axis and potential implications for menstrual patterns, estrogen production, and persistent consequences,” Dr Kontos and colleagues concluded.

Study Limitations

  • Self-report of menstrual data is subjective and does not confirm the quality of the menstrual cycle (for example, whether ovulation is occurring or ovarian estrogen production is appropriate).
  • Obtaining serial biological specimens for hormonal assays was not possible
  • Researchers did not assess long-term menstrual status
  • Results may not be applicable to prepubescent girls, individuals within the first 2 years of menarche, individuals with preexisting abnormal menstrual cycles, or individuals with anxiety or depression


Snook ML, Henry LC, Sanfilippo JS, Zeleznick AJ, Kontos AP. Association of concussion with abnormal menstrual patterns in adolescent and young women [published online July 3, 2017]. JAMA Pediatr. doi:10.1001/jamapediatrics.2017.1140