The recently published study, "Menstrual Phase as Predictor of Outcome After mTBI in Women" is so exciting because this study goes a step beyond confirming that women's concussions are different than men's. This research explored why in detail the differences occur within the subset of women themselves compared to men's experience of concussion. The authors of the study are Kathryn Wunderle, BA; Kathleen M. Hoeger, MD, MPH; Erin Wasserman, BA; Jeffrey J. Bazarian, MD, MPH, of The University of Rochester.
I will now offer my layman's view of this study; and as always, I encourage you to read the original study posted below. Please feel free to correct/comment on my thoughts and send me any questions you would like me to pass on to the research team who conducted the study. I will post questions and responses in my next blog.
Many of us who have experienced concussions or worked with women with mTBI have long felt there was a connection between concussion and a woman's cycle. In this study, researchers sought to prove the “Withdrawal Hypothesis,” which states that if a woman has a high level progesterone in her body at the time of an injury, she will experience sudden drop in progesterone. And that it is this decrease or "drop" that will cause worse concussion outcomes than a woman who had low level of progesterone at the time of injury and did not experience this "drop."
So who has a low level of progesterone (thought to be beneficial at the time of a concussion)?
- Men always naturally have low progesterone.
- Girls do before they get their first period.
- Women do, in later life, after their periods have ended.
Who has a high level of progesterone?
- Women of child-bearing years who progesterone levels rise and fall depending on the week of their cycle.
Researchers in this study hypothesized that women who experience mTBI during part of their cycles when progesterone is high, would have worse outcomes than women injured during time in their cycles when their progesterone is low.
Does anyone has level of progesterone which is resistant to this "drop?"
- Women taking birth control do not experience a drop as the pill provides constant high levels of synthetic progestins.
Remember in the case of this study, low progesterone levels at the time of concussion were predicted to be beneficial as they did not "drop" because they were low at the start. High levels which were subject to the "drop" were thought to predict poor outcomes.
The final results of this study support the researchers' prediction that women in their cycle where "progesterone is highest, had worse post-concussion symptoms" than women whose progesterone is initially low. Similarly, women who were taking synthetic progestin as birth control seemed to mirror the women who were in the low progesterone phases.
The authors of the study warn that their findings must be "considered preliminary." Yet, they believe if their conclusions are "confirmed by others, it has important implications for both treatment and prognosis."
My mind races with the possibilities...
- Could this study be the starting point for a future hormone screening test - or even for a doctor to ask a simple question about when was an injured woman's last period?
- Could this simple screen alert doctors which women are more at risk and need more aggressive interventions?
- Could women in these risk groups based on their cycles be treated with progesterone after TBI?
As with every finding in the concussion field, more research needs to be done. But this study supports the hypothesis that the acute withdrawal of progesterone after mTBI may be the missing link (or one of the missing links) to why differences are seen in men and women's concussions. And in my opinion, this is a huge news for the concussion world - for men and women alike.
Objective: To determine whether menstrual cycle phase in women at the time of mild traumatic brain injury (mTBI) predicts 1-month outcomes.
Setting: Six emergency departments; 5 in Upstate New York, and 1 in Pennsylvania.
Participants: One hundred forty-four female participants (age, 16-60) who presented to participating emergency departments within 4 hours of mTBI.
Design: Nested cohort study with neurologic and quality-of-life outcome assessment, 1 month after enrollment. Female subjects aged 16 to 60 enrolled in the parent cohort study, with 1- month neurological determination data available, were classified into menstrual cycle groups by serum progesterone concentration and self-reported contraceptive use. Main Measures: Rivermead Post Concussion Questionnaire and EuroQoL/EQ5D.
Results: Women injured during the luteal phase of their menstrual cycle, when progesterone concentration is high, had significantly lower EuroQoL General Health Ratings and Index Scores than women injured during the follicular phase of their cycle or women taking oral contraceptives. Multivariate analysis confirmed a significant independent effect of menstrual cycle phase on EuroQoL Index Score and the Rivermead Post Concussion Questionnaire Somatic Subscore.
Conclusion: Menstrual cycle phase and progesterone concentration at the time of mTBI affect 1-month quality-of-life and neurologic outcomes. This association has important implications for treatment and prognosis after mTBI. Key words: brain concussion, brain injuries, follicular phase, luteal phase, menstrual cycle, postconcussion syndrome, progesterone, quality of life
Thank you to the authors - Kathryn Wunderle, BA; Kathleen M. Hoeger, MD, MPH; Erin Wasserman, BA; Jeffrey J. Bazarian, MD, MPH - and Leslie Orr of University of Rochester Medical Center - for allowing us to post this study.
Please direct questions to firstname.lastname@example.org if you would like to take part in our exchange with the authors of the study.