MONDAY, July 3, 2017 (HealthDay News) -- After a concussion, a young woman might notice that her next few menstrual periods are a bit off-schedule, a new study finds.
"The findings suggest that adolescent and young women have significantly increased odds of multiple, abnormal menstrual patterns following concussion, compared to those with an orthopedic injury," said lead researcher Anthony Kontos. He's director of research at the University of Pittsburgh Medical Center Sports Medicine Concussion Program.
"The odds of having two or more abnormal menstrual patterns were significantly higher -- six times higher for concussed patients, compared with those with orthopedic injuries," he said.
The study included 128 young women, aged 12-21. Sixty-eight had sports-related concussions and 60 had an orthopedic injury, such as muscle strains or tears or broken or fractured bones. Forty-five percent of these women had at least one abnormal period.
Nearly 24 percent of the women with a concussion had two or more abnormal menstrual bleeding patterns during the study period, compared with 5 percent of those with orthopedic injuries, Kontos said.
An abnormal menstrual pattern was defined by the researchers as less than 21 days apart, or more than 35 days apart. A woman's average menstrual cycle is about 28 days.
Kontos and his team followed the injured young women's health for 120 days. The women used text messages linked to an online survey to report their periods.
The exact connection between concussion and abnormal periods isn't known.
Concussions may affect ovarian function. And, the ovaries govern the menstrual cycle. So, changes in the ovaries could lead to hormonal disruption, which would alter bleeding patterns, Kontos said.
The study was published online July 3 in the journal JAMA Pediatrics.
Dr. Megan Moreno wrote an accompanying editorial in the same issue of the journal.
"These findings suggest that brain injuries, such as a concussion, may affect the hormonal processes involving estrogen and progesterone that are important in maintaining a regular menstrual cycle and female development via puberty and bone density," Moreno wrote. She is an adolescent medicine specialist at Seattle Children's Hospital.
"There is a need for more research to determine what the short- and long-term effects of these findings mean for the health of adolescents and young women," Kontos said.
"Health care providers should ask patients about menstrual patterns and encourage monitoring of menstrual function following a concussion," Kontos said.
Menstrual patterns were self-reported for the study. The researchers noted that self-reporting can leave the data open to possible errors. In addition, the researchers couldn't account for all factors that might affect menstrual patterns.
For more information on concussion, visit the U.S. Centers for Disease Control and Prevention.