Concussion in young female athletes: more common, less often spotted (and what to do in the first minutes)

In US high school soccer, girls sustain concussions at 1.88 times the rate of boys, and they are 1.26 times more likely not to be removed from activity after the hit. Athletes who keep playing recover in 44 days instead of 22 — and 60% of events are never reported to any adult. Neither a visible blow to the head nor loss of consciousness is required: the data, the sideline signs in the first minutes, and what the international guidelines actually say.

Nothing in a club's calendar matters more than the thirty seconds after a blow to the head. A collision, a ball taken badly, a fall on landing: the athlete gets up, says "I'm fine", and play restarts. Far more is decided in those thirty seconds than it seems — and the data say that, for girls, that decision goes wrong more often.

In brief

  • In Michigan high school soccer, girls had 1.88 times the concussion risk of boys (95% CI 1.69-2.09) (Bretzin et al., 2021).
  • Across sex-comparable sports, girls were 1.26 times more likely not to be removed from activity after the injury (Zynda et al., 2021).
  • Athletes who kept playing after a concussion recovered in 44.4 days versus 22.0 for those removed immediately, and were 8.8 times more likely to have protracted recovery (Elbin et al., 2016 — small, mixed-sex sample).
  • 60% of concussion events recalled by athletes had not been reported to any adult (Register-Mihalik et al., 2013).
  • The guidelines behind clinical management rest on studies whose samples are 80.1% male; 40.4% include no female athletes at all (D'Lauro et al., 2022).

Do girls sustain more concussions than boys?

In sports where a like-for-like comparison is possible, yes. The most solid data come from the Michigan High School Athletic Association head injury reporting system, which followed 43,741 male and 39,637 female high school soccer players across three seasons (2016-17 → 2018-19). Of 1,507 recorded concussions, 950 were in girls and 557 in boys: a risk 1.88 times higher for female athletes (95% CI 1.69-2.09) (Bretzin et al., 2021, JAMA Netw Open).

It isn't an isolated finding. In a different population — 3,465 males and 1,751 females aged 12-22, median age 15 — female athletes had 1.62 times higher odds of concussion (95% CI 1.40-1.86) (Hannah et al., 2021, Am J Sports Med).

Two honest caveats. First: this is US school sport, with dense injury surveillance and certified athletic trainers on the sideline — a context that simply doesn't exist in most of Europe, which makes the absolute numbers non-transferable. Second, and more important: why this difference exists is not explained. Several biomechanical and hormonal hypotheses circulate; none is currently established enough to be presented as fact. What can be said with confidence is that the difference is measured, repeated, and worth taking seriously.

Where the hit comes from, and why it changes everything

One detail in the Michigan data is worth more than a lot of discussion. The mechanism of injury differs by sex: among boys the most common cause is contact with another player (48.4%), among girls contact with an object — ball, goalpost, playing surface — (41.9%) (Bretzin et al., 2021).

Why does that matter? Because a body-to-body collision is visible: the referee whistles, the bench sees it, someone steps in. A ball taken badly on the head while play continues is not. The consequence shows up in the same data: boys were 1.54 times more likely to be removed from play immediately (95% CI 1.15-2.06; P = .004). Not because they were more careful — because their injury was easier to see.

The bigger problem isn't the hit: it's staying on the field

This is the part a club can change tomorrow, without buying anything.

A study of the same Michigan records analysed 4,418 concussions (2,773 in girls, 1,645 in boys) across 22 sex-comparable sports between 2016 and 2019. The result: 515 girls and 243 boys were not removed from activity at the time of the injury event — an incidence of 0.19 versus 0.15. Overall, girls were 1.26 times as likely not to be removed (95% CI 1.09-1.45), with the clearest value in soccer: 1.37 (95% CI 1.09-1.72) (Zynda et al., 2021, Am J Sports Med). In fairness, in the other sports analysed individually — basketball, baseball/softball, lacrosse — the confidence intervals cross 1: the difference is clear in aggregate, not in every discipline.

And staying on the field is costly. In a study of 69 athletes aged 12-19 seen at a specialist clinic, the group removed immediately recovered in a mean of 22.0 days; the group that kept playing, in 44.4 (p=.003). Those who stayed on were 8.8 times more likely to have protracted recovery beyond 21 days (Elbin et al., 2016, Pediatrics).

That sample is small, mixed-sex and clinic-referred: it is not definitive proof, and should be read with care. But it isn't isolated — the systematic review that informed the international consensus reaches the same conclusion: continuing to play and delayed access to a healthcare professional are associated with longer recovery (Patricios et al., 2023, Br J Sports Med).

Put the two together: girls come off later, and coming off later lengthens recovery. This isn't about fragility. It's about who is watching, and what they are able to see.

How often does nobody find out?

There is one last layer, and no reporting system catches it: the events the athlete never mentions.

In a study of 167 high school athletes (mean age 15.7; American football, soccer, lacrosse, cheerleading), 60% of recalled concussion events had not been disclosed to a supervising adult. For so-called "bell-ringers" — the hits that leave you dazed for a few seconds and get waved off — non-disclosure rose to 87% (Register-Mihalik et al., 2013, J Athl Train). It is a preliminary study on a small mixed-sex sample, but the direction matches the wider literature.

It is the same mechanism we have seen with urinary leakage and with periods: the symptom never reaches the person who has to decide what happens next. With one substantial difference — here the information that fails to travel concerns the brain, and the useful window is measured in minutes.

Recognising it on the sideline

You don't need a visible blow to the head, and you don't need loss of consciousness: in most concussions it doesn't happen. The Amsterdam 2022 international consensus lists the signs that warrant immediate removal from play (Patricios et al., 2023):

The operating rule admits no nuance: if a concussion is suspected, the athlete comes off. Anyone showing one of those signs does not return that day, unless acutely evaluated by an experienced healthcare professional. The consensus also notes that symptoms may evolve over minutes, hours or days: an athlete who seems fine at full time still needs re-evaluation in the hours that follow.

One detail that often gets missed: symptoms aren't only physical. Confusion, irritability, trouble concentrating, disturbed sleep. On sleep specifically, the consensus notes that sleep disturbance in the 10 days after a concussion is associated with an increased risk of persisting symptoms — another reason a teenage athlete's sleep isn't a detail.

What comes next: relative rest, not a dark room

Here the Amsterdam consensus overturned a widespread belief. In its own terms: the best available evidence shows that recommending strict rest until complete symptom resolution is not beneficial. What it advises instead is (Patricios et al., 2023):

Final clearance to return to activities at risk of contact is a healthcare professional's decision, in writing where local rules require it. Not the coach's, not the family's, not the athlete's.

Do female athletes recover more slowly?

This is the question that generates the most confusion, and it deserves a precise answer rather than a slogan.

In the Michigan soccer data, boys returned two days sooner: median 10 days (IQR 7-14) versus 12 (IQR 7-16) (Bretzin et al., 2021). But once initial severity is controlled for, the difference disappears: across 5,216 post-injury evaluations there was no effect of sex on time to recovery (HR 0.94; 95% CI 0.78-1.12) (Hannah et al., 2021). In that same study, however, female athletes showed a higher initial severity index, driven by the number of symptoms reported.

The Amsterdam consensus points the same way: similar return-to-learn and return-to-sport strategies can be implemented across different cohorts (age, sex) with minimal differences in time to recovery.

Taken together, the picture isn't "girls heal worse". It is: girls more often arrive at diagnosis in a worse state, because they leave the field later and because they report more symptoms when someone finally asks. The intervention point isn't rehabilitation. It's the sideline.

The blind spot: guidelines built 80% on males

This is worth saying, because it changes how every number above should be read.

One analysis examined the 171 studies cited by the three most influential consensus and position statements on sport-related concussion (NATA 2014, ICCS 2017, AMSSM 2019). The samples underpinning those recommendations are 80.1% male, and 40.4% of the studies include no female participants at all (D'Lauro et al., 2022, Br J Sports Med).

The Amsterdam consensus acknowledges it too: in its prevention section it notes that neuromuscular warm-up programmes are recommended based on research in rugby, and that more research is needed in female athletes and in other team sports to identify which components actually reduce concussion rates. It also notes that empirical data are limited for preadolescent, female and para athletes.

It is the same gap that runs through all of women's sports medicine: only 6% of sport and exercise science studies are conducted exclusively on women (Cowley et al., 2021). We have already told that story for the ACL: protocols that work do exist, and they are the very warm-up the consensus refers to.

What a club can do, starting Monday

None of these is a medical prescription. They are organisational decisions, at zero cost:

The logic is the same one that applies to injuries that are far more frequent and far less dramatic: what decides the outcome is not the severity of the hit, but whether somebody watches and writes it down. It holds for the ACL and it holds, almost as a mirror image, for the ankle sprain — the most common injury in youth female athletes, and the one nobody records because "it's nothing".

Where BAB fits

BAB does not diagnose concussion and does not replace any clinical evaluation: no app can, and anyone promising otherwise deserves suspicion. What BAB does is more modest and complementary: it helps the athlete notice and record privately how she is — headache, fatigue, concentration, sleep, mood — so that a departure from her own normal becomes visible to her first, instead of dissolving into an "I'm fine" said on the run. Clubs receive only aggregated, anonymous signals. Because the problem here isn't a lack of protocols: it's that the decisive piece of information starts with a fourteen-year-old who has no reason yet to say it out loud.

Sources

This article is for information only and does not constitute medical advice or a diagnostic tool. If a concussion is suspected, the athlete should be removed from activity immediately and evaluated by a healthcare professional; return to play should be authorised by someone with the clinical competence to do so.

Are girls at higher risk of concussion than boys?

In the available data, yes — in sports where a like-for-like comparison is possible. In Michigan high school soccer, across 83,378 athletes followed for three seasons, girls had 1.88 times the concussion risk of their male peers (95% CI 1.69-2.09): 950 cases among girls versus 557 among boys (Bretzin et al., 2021). A separate study in a 12-22 year old population estimated 1.62 times higher odds in females (95% CI 1.40-1.86) (Hannah et al., 2021). These are US school-sport data: the direction is consistent, but the reason remains largely unexplained.

How do you recognise a concussion on the sideline?

You don't need a visible blow to the head, and you don't need loss of consciousness. The Amsterdam 2022 consensus lists signs that warrant immediate removal from play: actual or suspected loss of consciousness, seizure, tonic posturing, ataxia or motor incoordination, poor balance, confusion, behavioural changes, amnesia (Patricios et al., 2023). There is one rule: if a concussion is suspected, the athlete comes off. Players showing those signs should not return to the match or training that day unless acutely evaluated by an experienced healthcare professional.

Why does coming off immediately matter so much?

Because recovery time changes. In a study of 69 athletes aged 12-19 seen at a specialist clinic, those removed immediately recovered in a mean of 22.0 days, those who kept playing in 44.4 (p=.003), and the latter were 8.8 times more likely to have protracted recovery beyond 21 days (Elbin et al., 2016). It is a small, mixed-sex, clinic-referred sample — not a law — but the systematic review underpinning the Amsterdam consensus points the same way: continuing to play and delayed access to healthcare professionals are associated with longer recovery (Patricios et al., 2023).

After a concussion, should the athlete stay in a dark room and do nothing?

No, and this is one of the most-changed recommendations of recent years. The Amsterdam 2022 consensus states that recommending strict rest until symptoms fully resolve is not beneficial: it advises relative rest (activities of daily living and reduced screen time) for up to the first 2 days, with light-intensity activity such as walking that does not more than mildly exacerbate symptoms during the first 24-48 hours, and an early return to as-tolerated physical activity after 24-48 hours while avoiding any risk of contact, collision or fall (Patricios et al., 2023). The return-to-sport strategy has 6 steps, each typically lasting at least 24 hours, and should be managed with a healthcare professional.

Do female athletes recover more slowly?

The honest answer is: it depends what you control for. In high school soccer, boys returned a median 2 days sooner (10 days versus 12) (Bretzin et al., 2021). But a study of 5,216 post-injury evaluations found no effect of sex on time to recovery once initial concussion severity was accounted for (HR 0.94; 95% CI 0.78-1.12) (Hannah et al., 2021), and the Amsterdam consensus reports that similar return-to-learn and return-to-sport strategies can be applied across cohorts with minimal differences in recovery time (Patricios et al., 2023). Rather than recovering worse, the data suggest girls often start from a worse position: they come off the field later.

How long before an athlete can play again?

The Amsterdam consensus reports an estimated pooled mean of about 19.8 days (95% CI 18.8-20.7; 57 studies) to unrestricted return to sport across children, adolescents and adults, noting that clinicians and athletes can expect a minimum of one week to complete the progression and that typical unrestricted return can take up to a month post-injury (Patricios et al., 2023). Full return to learn should be completed before unrestricted return to sport, and the final clearance is a healthcare professional's call — not the coach's and not the family's.

Does someone have to lose consciousness for it to be a concussion?

No, and this is one of the most widespread sideline misunderstandings. The Amsterdam 2022 international consensus defines concussion as a traumatic brain injury induced by biomechanical forces: it requires neither loss of consciousness nor even a visible blow to the head — the force can be transmitted to the head from an impact elsewhere in the body (Patricios et al., 2023). Waiting for an athlete to "black out" before taking the episode seriously means not taking most cases seriously.

How many concussions are never reported to anyone?

A very high proportion. In a preliminary study of 167 high school athletes of both sexes (mean age 15.7), 60% of the events athletes recalled had not been reported to a responsible adult; for hits perceived as minor (so-called "bell-ringers") the non-reporting share rose to 87% (Register-Mihalik et al., 2013). That is why a club cannot build its safety on self-reporting: an adult has to observe and decide.

Were the concussion guidelines built on female athletes too?

Only partly, and it is worth knowing. An evidence review of the research behind the three most influential consensus statements on sport-related concussion examined the 171 studies cited: samples are 80.1% male, and 40.4% of studies include no female athletes at all (D'Lauro et al., 2022). This does not mean the recommendations are wrong — it means that on differences specific to girls, the evidence is thinner than the confidence of the language suggests.