Pregnancy itself wasn't the injury risk military doctors expected, a big study finds

A study presented at the Military Health System Research Symposium in Kissimmee, Florida, which concluded 6 August, found that active-duty servicewomen had lower overall rates of musculoskeletal injury during pregnancy and the year following delivery than during their non-pregnant periods — the opposite of what researchers said they expected going in [s1].

What the study looked at

Dr. Elizabeth Hisle-Gorman, an associate professor of pediatrics at the Uniformed Services University, analyzed military health records from 2013 to 2025, comparing more than 2.5 million non-pregnant person-years against periods of pregnancy and the postpartum year [s1]. The injuries tracked were strains, sprains, and stress fractures — the category of musculoskeletal injury most directly tied to military physical readiness [s1]. Using person-years as the comparison unit is a standard way to account for the fact that people spend different amounts of time in each state (pregnant, postpartum, neither), rather than simply comparing raw injury counts.

The counterintuitive headline, and the exception to it

Overall, injury rates were lower during pregnancy and the postpartum year than during non-pregnant periods [s1] — the researchers' framing, and the reporting on it, both describe this as contradicting expectations, though the available reporting does not specify the exact percentage difference or which comparison periods were used as the baseline. That gap matters: "lower" without a magnitude is a real but incomplete finding, and readers should wait for the full published results, if and when they appear in a peer-reviewed journal, before treating the size of the effect as established.

The exception was localized and consistent: spine and back injuries increased during pregnancy, and spine, back, and upper-body injuries increased during the postpartum year [s1]. That pattern is plausible on its face — pregnancy shifts center of gravity and loosens connective tissue, and the postpartum period adds infant-carrying and altered sleep and movement patterns — but the study as reported doesn't establish the mechanism, only the association.

Hisle-Gorman's stated takeaway focuses on that exception rather than the reassuring topline: "Protecting the back...deserves special attention in prenatal and postpartum care" [s1].

Why this doesn't settle the broader question

This is one dataset, from one health system, covering active-duty service members — a population that is generally younger, fitter, and under closer medical monitoring than the general population of pregnant people, which limits how far the findings generalize. The analysis also doesn't appear to break results out by trimester, so it can't say whether risk is flat across pregnancy or concentrated in a particular stage. And as with any finding presented at a research symposium rather than published in a peer-reviewed journal, the numbers haven't yet been through independent peer review — a step that can surface methodological issues or shift the reported findings before final publication.

What to watch next

Whether this pattern replicates outside a military population, and whether a published, peer-reviewed version of the study reports the exact injury-rate differences that the symposium presentation apparently did not. On the practical side, the study's authors are reported to be recommending that pelvic floor screening be added to orthopedic rehabilitation protocols and that military hospitals open to civilian maternity patients [s1] — proposals that would follow from the back-and-spine finding specifically, not from the overall injury-rate result.