Young women who suffer a concussion during adolescence may experience dysfunction in their hypothalamic-pituitary-ovarian (HPO) axis leading to an abnormal menstrual cycle.
It is estimated that in the United States as many as 1.9 million children each year under the age of 18 experience a sport or recreation-related concussion. According to statistics, girls have higher rates of sport-related concussion, report more severe symptoms, and take longer to recover than boys involved in comparable activities.
The mechanisms behind these post concussion differences have been attributed to differences in female and male physiology, neuroanatomy, and levels of estrogen and progesterone. In females, the menstrual cycle is governed by the hypothalamic-pituitary-ovarian (HPO) axis and any functional disruption of this axis could lead to irregularities in bleeding patterns associated with menstruation. It is crucial to identify and manage signs of menstrual irregularities such as the cessation of menstruation (amenorrhea) and infrequent menstruation (oligomenorrhea) in young adolescent women because both may be associated with the development of low estrogen states and subsequent decreased bone mineral density. If concussions alter the HPO axis in young women and lead to abnormal menstrual cycles, being able to identify postconcussive status early could help clinicians identify and manage any individual with abnormal menses.
This study, published in JAMA Pediatrics, set out to determine the association between concussions and the development of abnormal menstrual cycles in young women. The researchers hypothesized that adolescent women with concussion would be more likely to have irregular menstrual bleeding patterns after their injuries than would those who experience sport-related orthopedic injuries.
In order to assess this association Snook and colleagues compared the menstrual patterns in 128 young women between the ages of 12 to 21 with sport-related concussions (n=68) to those with sport-related orthopedic (non-head) injuries (n=60). The study included female patients who presented to the University of Pittsburgh Medical Center Sports Concussion Clinic or Center for Sports Medicine, Pittsburgh, Pennsylvania with closed head injuries or nonhead orthopedic injuries in the preceding 30 days.
Participants had to be at least two years postmenarche (started menstruating two or more years ago), have regular menstrual cycles in the previous year, be English speaking, and have access to a smartphone to receive text messages. Each week the patients received an automated text message containing a link to an online Qualtrics survey that collected data about possible bleeding episodes, new injuries experienced, use of hormonal contraception, and whether they were or could be pregnant. After enrolment, patients received text messages up to 120 days after their injury (range 90-120 days), which translated to 3 to 4 menstrual cycles for each patient.
The primary outcome of interest was the development of an abnormal post-injury menstrual pattern. The researchers considered 2 or more of the following as an indication of dysfunction: intermenstrual interval of less than 21 days, intermenstrual interval of greater than 35 days, a bleeding duration of less than 3 days and/or a bleeding duration of greater than 7 days.
What the researchers found was that of the 68 patients who had a concussion, 16 reported experiencing an abnormal menstrual cycle during the study period, compared with 3 of the 60 patients who had orthopedic (non-head) injuries. Patients with concussions reported risk of having short (<21 days) intermenstrual intervals compared with the control group. No patients reported amenorrhea over the duration of this study.
There were a few limitations to the study including the reliance on self-report of menstrual patterns. Obtaining serial biological specimens of hormonal assays was not feasible, however, self-reporting did not confirm whether ovulation occurred and/or whether ovarian estrogen production was appropriate. The researchers did not assess long-term menstrual status to determine any effect concussions may have on end-points such as bone health.
The study is important because subtle forms of brain injury such as concussions have the potential to affect the HPO axis function and can result in negative downstream effects on the menstrual cycle in adolescent women. Estrogen plays an important role in young women to stimulate the development of secondary sexual characteristics and is critical for building bone mass. Clinicians who treat adolescent women who have suffered concussions should inquire about menstrual patterns to identify the patients who may develop abnormal menses.
Written By Kimberly Spencer B.Sc. (Hons)
Snook, Meredith L. et al. “Association Of Concussion With Abnormal Menstrual Patterns In Adolescent And Young Women.” JAMA Pediatrics, 2017, American Medical Association (AMA), doi:10.1001/jamapediatrics.2017.1140