Title: Prevalence of Menstrual Alterations Following COVID-19 Vaccination: Systematic
Review & Meta-Analysis
Version: 2 Date: 19 Jul 2024
Reviewer's report:
PEER REVIEWER ASSESSMENTS:
OBJECTIVE - Full research articles: is there a clear objective that addresses a testable research
question(s) (brief or other article types: is there a clear objective)?
No - there are minor issues
DESIGN - Is the current approach (including controls and analysis protocols) appropriate for
the objective?
No - there are minor issues
EXECUTION - Are the experiments and analyses performed with technical rigor to allow
confidence in the results?
No - there are minor issues
STATISTICS - Is the use of statistics in the manuscript appropriate?
Yes - appropriate statistical analyses have been used in the study
INTERPRETATION - Is the current interpretation/discussion of the results reasonable and not
overstated?
No - there are major issues
OVERALL MANUSCRIPT POTENTIAL - Is the current version of this work technically
sound? If not, can revisions be made to make the work technically sound?
Probably - with minor revisions
PEER REVIEWER COMMENTS:
GENERAL COMMENTS: I read carefully the paper "Prevalence of Menstrual Alterations
Following COVID-19 Vaccination: Systematic Review & Meta-Analysis". Overall, this
manuscript is comprehensive and informative, providing a solid foundation through a systematic
review and meta-analysis. The methods section is well-structured and detailed, adhering to
high standards of systematic review methodology. With improvements in clarity, citation
consistency, coherence, the paper will be more impactful and easier to follow.
REQUESTED REVISIONS:
I recommend to take into account the following suggestions:
- The text needs to be edited by a native speaker in order to improve grammar and style.
- Introduction: Some sentences are lengthy and complex, potentially confusing the reader.
Consider breaking them into shorter, more precise sentences.
- Introduction: Phrases like "marked the beginning of a global health crisis" and "leading to
a rapid escalation of COVID-19 cases worldwide" are repetitive. Streamline the text to avoid
redundancy.
- Introduction: Ensure all statements, especially those involving statistics or claims about public
health impacts, are supported by citations. For example, the statement about the reduced rates
of hesitancy needs a citation.
- Introduction: Maintain consistent formatting for citations. Some citations are within sentences,
while others are at the end. Ensure uniformity for better readability.
- Introduction: I recommend to discuss that COVID-19 vaccine was associated with menstrual
cycle irregularities, which were found to self-resolve in approximately half the cases within two
months (authors may refer to: PMID: 35350834; PMID: 36804196).
- Introduction: Better link the discussion on immune mechanisms with the concerns about
menstrual changes. This connection is vital to understanding why menstrual cycle changes could
occur post-vaccination.
- Introduction: Clearly define the target population for the study. Mention that the focus is on
adult women to maintain clarity.
- Introduction: Explicitly state the research question or hypothesis being addressed. The aim is
mentioned at the end, but an earlier, clear statement of the study's purpose would enhance focus.
- Methods: Ensure consistent use of terms throughout the section. For instance, "review of the
criteria previously mentioned" could be rephrased for clarity.
- Methods: Minor grammatical errors need correction for clarity, such as "ad-ministered vaccine"
should be "administered vaccine."
- Methods: While the search terms are provided, it would be helpful to include the exact Boolean
search strings used. This enhances reproducibility.
- Methods: Specify how disagreements during the initial screening were resolved. Did the third
author review all discrepancies or only unresolved ones?
- Methods: The definitions of menstrual changes could be made more precise. For example,
clarify if "flow" measurement is self-reported or clinically measured.
- Methods: Explicitly state how outcomes were measured and reported across studies to ensure
consistency.
- Methods: When mentioning a "modified version of the Newcastle–Ottawa scale" for cross-
sectional studies, specify what modifications were made and why.
- Methods: Provide more detail on the choice between fixed effects and random effects models.
When is each used, and why?
- Methods: was this systematic review registered on PROSPERO or a similar international
repository? If the authors did not register it, they should explain why.
- Results: The introduction to the study selection process is clear, but the exclusion reasons
should be grouped more logically. This would enhance readability.
- Discussion: The paragraph structure can be improved for better readability. Some sentences
are overly complex and could benefit from simplification.
- Discussion: The authors should discuss the novel data suggesting changes in menstrual volume
and changes in menstrual cycle length as consequences of SARS-CoV-2 infection, namely
decreased menstrual volume and a prolonged cycle, which seem independent by the severity of
COVID-19 (authors may refer to: PMID: 35807090; PMID: 36836546).
- Discussion: The paragraph structure can be improved for better readability. Some sentences
are overly complex and could benefit from simplification.
- Discussion: The percentages and statistics should be presented consistently (e.g., always use
either "percent" or "%").
- Discussion: The discussion could benefit from a deeper analysis of the underlying biological
mechanisms for menstrual changes post-vaccination.
- Discussion: Expand on why certain menstrual changes, like heavier flow, might be more
prevalent.
- Discussion: The discussion mentions inconsistent findings but does not delve deeply into
possible reasons for these discrepancies.
- Discussion: Consider including a more detailed comparison of studies with conflicting results
to provide a clearer picture of the state of the research.
- Discussion: The limitations section is somewhat brief. Expanding on the specific limitations
of the included studies (e.g., reliance on self-reported data, short follow-up periods) would be
beneficial.
- Discussion: Future research directions are mentioned but could be more detailed. Specify
what kind of prospective cohort studies are needed, including potential study designs and key
variables to control.
- Discussion: The implications for public health strategies are mentioned briefly. This section
could be expanded to include more specific recommendations for policy makers and healthcare
providers.
- Discussion: Discuss potential public health messaging strategies to address concerns about
menstrual changes post-vaccination.