PLOS One Flags 2024 Pelvic Floor Muscle Study Over Peer Review Integrity Concerns

A 2024 study that measured the electrical activity of pelvic floor muscles while volunteers used an innovative vaginal training device has been placed under an Expression of Concern by the editors of PLOS One, one of the world’s largest open-access scientific journals. The notice, published on October 19, 2026, does not retract the paper, but it formally warns the scientific community that the journal has identified problems affecting confidence in how the work reached print. The flagged paper, a cross-sectional study led by researchers including N. d. S. Duarte and colleagues, originally appeared in March 2024 and examined electromyographic readings from the pelvic floor muscles of participants placed in different body positions during use of the device.

According to the editorial notice, the decision stems from a broader review rather than from a specific dispute about the study’s data. The PLOS One Editors state that the article was identified as one of a series of submissions about which the journal has concerns regarding the integrity and reliability of the peer review process. In other words, the question is not, at least so far, whether the measurements themselves are accurate, but whether the manuscript was properly vetted by independent experts before publication. That distinction matters, because peer review is the mechanism that journals rely on to filter out flawed methods, unsupported conclusions, and undisclosed conflicts before a paper becomes part of the citable literature.

The notice is notable for what it does and does not assert. PLOS explicitly states that it did not evaluate the article’s integrity or scientific validity while following up on the matter, and readers are advised to interpret the paper with consideration of the peer review concerns. This is a deliberately cautious formulation. An Expression of Concern sits below a full retraction in the hierarchy of post-publication corrections: it signals unresolved doubt, keeps the paper in the database so that other researchers can still find and cite it, and reserves judgment until an investigation concludes or the situation is otherwise resolved. Journals typically resort to this notice when concerns are credible but the underlying facts have not yet been fully established.

Equally significant is what the editors say about the authors. The notice records that PLOS has no evidence of any author involvement in the peer review concerns. That statement matters because schemes in which reviewers fake their own identities or coordinate approving reviews, sometimes called peer review rings, have historically implicated authors who submitted fabricated reviewer email addresses. By stating that no author involvement is suspected here, PLOS is locating the problem elsewhere in the pipeline, while leaving open exactly where the failure occurred. The editors also note that the academic editor listed on the article is a PLOS staff editor who was not involved in the concerns and was unaware of the peer review issues before the article was published, an apparent attempt to shield that individual from unfair inference.

The underlying study itself addressed a clinically active area of research. The pelvic floor muscles form a hammock-like group of fibers spanning the base of the pelvis, and weakness or dysfunction in these muscles is associated with urinary incontinence, pelvic organ prolapse, and other conditions that affect a large share of the population, particularly after childbirth and with advancing age. Electromyography, or EMG, is the standard tool for assessing such muscles noninvasively: surface or intravaginal electrodes detect the tiny electrical signals generated when muscle fibers contract, allowing researchers and clinicians to quantify activation strength and timing. Because the pelvic floor is invisible from outside the body and difficult to activate consciously, biofeedback devices that help patients learn correct muscle engagement have become a focus of physiotherapy research.

Against that background, the flagged paper evaluated electromyographic activity of the pelvic floor muscles in different body positions while participants used what the authors describe as an innovative vaginal educator, a device intended to teach patients how to locate and contract the right muscles. Posture is genuinely consequential in this field, because muscle activation measured standing can differ from activation measured lying down, and rehabilitation protocols often specify positions accordingly. A device that reliably guides patients through contractions in multiple positions could, in principle, improve home-based pelvic floor training, which is why such cross-sectional comparisons attract clinical interest. The Expression of Concern does not dispute the plausibility of that research question; it concerns the process by which the report was reviewed.

The mechanics of peer review, when it functions as designed, are straightforward. A journal editor sends a manuscript to two or more independent experts, who assess the methods, statistics, and interpretations and recommend acceptance, revision, or rejection. The system’s weakness is its dependence on trust: reviewers are usually invited based on email addresses supplied with the manuscript or drawn from a database, and journals historically have had limited tools to verify that a reviewer is who they claim to be. Large open-access journals that process tens of thousands of submissions each year are particularly exposed to abuse at scale, and several publishers have spent recent years tightening identity checks, cross-referencing reviewer accounts, and screening submissions for telltale signs of coordinated manipulation.

PLOS has been among the publishers most visibly affected by such schemes. The publisher has previously issued mass retractions involving large numbers of papers in which peer review was compromised, and expressions of concern have become its preferred instrument when an investigation is incomplete. Grouping this article into a series of submissions with related concerns suggests the journal detected a pattern, perhaps through shared reviewer identities, overlapping manuscript characteristics, or anomalies flagged by screening software, and has chosen to annotate every affected paper rather than quietly removing any single one. That approach preserves transparency: readers, funders, and institutions can see the warning attached directly to the record, and the scientific record is amended rather than erased.

For clinicians and researchers who cite the pelvic floor study, the practical consequences are immediate. Citation managers and databases such as PubMed will continue to list the paper, which appeared in PLOS One in March 2024 and carries PubMed identifier 38536803, but the Expression of Concern is now part of its permanent record, linked through the digital object identifiers of both the notice and the original article. Authors citing the work are expected to disclose the notice; failure to do so can itself be treated as a reporting omission. For patients, the direct implications are more limited, since a single cross-sectional measurement study does not by itself set treatment guidelines, but the episode underscores why rehabilitation devices and protocols should be adopted on the strength of multiple, independently reviewed lines of evidence rather than one publication.

The case also illustrates a broader shift in how science polices itself. Post-publication notices were once rare and carried stigma; they are now a routine tool that allows journals to respond quickly to suspected problems without waiting years for institutional investigations to run their course. Whether this particular study is ultimately validated, corrected, or retracted, the record now tells readers exactly what is known and what remains unresolved: the journal has doubts about the reliability of the peer review that preceded publication, no evidence against the authors, and no finding on the science itself. In an era when a single paper can shape clinical practice within months of appearing online, that calibrated honesty may be the notice’s most valuable contribution.

Subject of Research: Peer review integrity concerns surrounding a 2024 PLOS One study of pelvic floor muscle electromyography during use of a vaginal educator device

Article Title: Expression of Concern: Electromyographic activity of pelvic floor muscles in different positions during the use an innovative vaginal educator: Cross-sectional study

Article References: The PLOS One Editors (2026). Expression of Concern: Electromyographic activity of pelvic floor muscles in different positions during the use an innovative vaginal educator: Cross-sectional study. PLOS One, 21(10), e0360775. https://doi.org/10.1371/journal.pone.0360775

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360775

Keywords: PLOS One, Expression of Concern, peer review, research integrity, pelvic floor muscles, electromyography, vaginal educator, biofeedback, open access, cross-sectional study, publication ethics, post-publication correction