Association of Concussion With Abnormal Menstrual Patterns in Adolescent and Young Women.

Importance: Brain injury may interrupt menstrual patterns by altering hypothalamic-pituitary-ovarian axis function. Investigators have yet to evaluate the association of concussion with menstrual patterns in young women.

Objective: To compare abnormal menstrual patterns in adolescent and young women after a sport-related concussion with those after sport-related orthopedic injuries to areas other than the head (nonhead).

Design, Setting, And Participants: This prospective cohort study of adolescent and young women with a sport-related concussion (n = 68) or a nonhead sport-related orthopedic injury (n = 61) followed up participants for 120 days after injury. Patients aged 12 to 21 years who presented within 30 days after a sport-related injury to a concussion or sports medicine clinic at a single academic center were eligible. Menstrual patterns were assessed using a weekly text message link to an online survey inquiring about bleeding episodes each week. The first patient was enrolled on October 14, 2014, and follow-up was completed on January 24, 2016. Inclusion criteria required participants to be at least 2 years postmenarche, to report regular menses in the previous year, and to report no use of hormonal contraception.

Exposures: Sport-related concussion or nonhead sport-related orthopedic injury.

Main Outcomes And Measures: Abnormal menstrual patterns were defined by an intermenstrual interval of less than 21 days (short) or more than 35 days (long) or a bleeding duration of less than 3 days or more than 7 days.

Results: A total of 1784 survey responses were completed of the 1888 text messages received by patients, yielding 487 menstrual patterns in 128 patients (mean [SD] age, 16.2 [2.0] years). Of the 68 patients who had a concussion, 16 (23.5%) experienced 2 or more abnormal menstrual patterns during the study period compared with 3 of 60 patients (5%) who had an orthopedic injury. Despite similar gynecologic age, body mass index, and type of sports participation between groups, the risk of 2 or more abnormal menstrual bleeding patterns after injury was significantly higher among patients with concussion than among those with an orthopedic injury (odds ratio, 5.85; 95% CI, 1.61-21.22).

Conclusions And Relevance: Adolescent and young women may have increased risk of multiple abnormal menstrual patterns after concussion. Because abnormal menstrual patterns can have important health implications, monitoring menstrual patterns after concussion may be warranted in this population. Additional research is needed to elucidate the relationship between long-term consequences of concussion and the function of the hypothalamic-pituitary-ovarian axis.