There’s an increased risk that girls will have irregular periods after they experience a concussion, according to a study published Monday in JAMA Pediatrics. The authors surveyed 128 girls and women aged 12 to 21 who had either a head injury or an orthopedic injury from athletic or recreational activity within the 30 days before the study started. Nearly a quarter of the 68 girls who had concussions — 23.5% — experienced two or more abnormal bleeding patterns in the 120 days after their injuries, while only 5% of the 60 girls without concussions had the same irregularity.
The irregular periods are caused by the disruption of the neuroendocrine hypothalamic-pituitary-ovarian axis, which can occur from concussion, according to the study. This refers to the part of the brain that helps develop and regulate the body’s reproductive and immune systems. Short-term effects of irregular periods can include reduced estrogen production, according to the study. Potential long-term effects are reduced bone mineral density and delayed development of secondary sexual characteristics, which is related to a reduction in estrogen.