Dear Dr. Chaichian,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by May 22 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

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We look forward to receiving your revised manuscript.

Kind regards,

Mohammad Haddadi, MD

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf .

2. Please provide a complete Data Availability Statement in the submission form, ensuring you include all necessary access information or a reason for why you are unable to make your data freely accessible. If your research concerns only data provided within your submission, please write "All data are in the manuscript and/or supporting information files" as your Data Availability Statement.

3. Please include a separate caption for each figure in your manuscript.

4. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information .

5. As required by our policy on Data Availability, please ensure your manuscript or supplementary information includes the following:

A numbered table of all studies identified in the literature search, including those that were excluded from the analyses. 

For every excluded study, the table should list the reason(s) for exclusion. 

If any of the included studies are unpublished, include a link (URL) to the primary source or detailed information about how the content can be accessed.

A table of all data extracted from the primary research sources for the systematic review and/or meta-analysis. The table must include the following information for each study:

Name of data extractors and date of data extraction

Confirmation that the study was eligible to be included in the review. 

All data extracted from each study for the reported systematic review and/or meta-analysis that would be needed to replicate your analyses.

If data or supporting information were obtained from another source (e.g. correspondence with the author of the original research article), please provide the source of data and dates on which the data/information were obtained by your research group.

If applicable for your analysis, a table showing the completed risk of bias and quality/certainty assessments for each study or outcome.  Please ensure this is provided for each domain or parameter assessed. For example, if you used the Cochrane risk-of-bias tool for randomized trials, provide answers to each of the signalling questions for each study. If you used GRADE to assess certainty of evidence, provide judgements about each of the quality of evidence factor. This should be provided for each outcome. 

Additional Editor Comments (if provided):

Your manuscript and topic are suitable. However, I believe several modifications are necessary for improvement:

1. Avoid abbreviations in the abstract, such as “PI,” unless they are first fully spelled out.

2.Review the entire manuscript for proper capitalization and make corrections where needed.

3. Rewrite the conclusion section in the abstract—it is currently unclear and needs to be more concise and informative.

4. Do not separate the introduction into “Rationale” and “Objective” sections. It is more standard to present the Introduction as a single, cohesive section.

5. Avoid using abbreviations without first providing their full form, such as “C-section” (line 51), “BMI” (line 86), and “ROB” (line 82).

6. Expand the Introduction by discussing other tools and assessments. Explain the significance of comparing uterine artery resistance with C-section history and clarify why this comparison matters. The importance of the study should be well articulated.

7. Include citations for reporting guidelines such as PRISMA. Do not use abbreviations like PRISMA before introducing and citing them properly.

8. Describe the Risk of Bias (ROB) assessment in detail in both the Methods and Results sections. Explain how the assessment was conducted and highlight specific limitations in the included studies. Do not just report qualitative ratings—also provide final scores alongside terms like “good,” “fair,” etc.

9. Specify the software package used for analysis in the Methods section.

10. As previously mentioned, discuss the Risk of Bias in detail in the Results section, including study-specific assessments.

11. Avoid repeating abbreviations like “Pulsatility Index (PI)” once already defined (e.g., in lines 129, 132, etc.).

12. Clearly state the aim of the study at the beginning of the Discussion, linking it directly to the outcomes.

13. Include full descriptions of any abbreviations used in tables in the footnotes.

14. Describe the Doppler assessment methodology for each included study—how it was performed and according to which guidelines.

17. According to the AMSTAR guidelines, it is recommended to report the source of funding for each included study, as this adds transparency.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: No

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3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Overall Appraisal

This meta-analysis and systematic review addresses a relevant clinical question by examining the association between prior cesarean section and uterine artery resistance in subsequent pregnancies. The study is well-structured, with a clear methodology, including a comprehensive literature search, independent study selection, and appropriate risk-of-bias assessment. However, before considering it for publication, the following key modifications are required:

Comments to The Authors

Abstract

• Line 38-40: It is not clear whether the authors are referring to PI or RI as a measure of uterine artery resistance here. I strongly recommend on reporting the results from the meta-analysis for both measures here.

Introduction

• Line 49-51: Please provide robust references for each cited sentence.

• Line 51: Please ensure consistent use of "cesarean section" throughout the manuscript, as "C-section" appears here.

• Line 65: Please state your hypothesis regarding the meta-analysis results based on existing literature, and discuss the potential clinical and research implications of your findings.

Methods

• Line 67: Before defining the eligibility criteria, please define your research question following the PICO framework.

• Line 68: Please define the abbreviations PRISMA and PROSPERO.

• Line 67-70: The current eligibility criteria lack sufficient precision for proper evaluation and require clarification. Please explicitly specify:

- The types of studies to be included (e.g., study designs, publication types)

- Detailed exclusion criteria (e.g., handling of non-peer-reviewed literature, non-original articles, non-human studies)

- Clear inclusion/exclusion parameters for different study designs

• Line 78: Please mention the EndNote version and company name.

• The authors must provide a new subsection describing the process of data extraction from each included study and mention what kind of data were systematically extracted from each study. Also, the review outcomes (RI and PR) should be defined here using robust references, e.g., ACOG or UOG guidelines.

• Line 82: Please define the abbreviation ROB.

• Line 82-83: The authors must define how each item of NOS was answered and how the overall appraisal of the quality of each study was made.

• Line 96: While the authors' use of Egger's test for publication bias assessment is appropriate, its reliability may be limited given the small number of included studies (n=6). We strongly recommend supplementing these results with funnel plots for each meta-analysis, as they would provide (1) visual objectivity for assessing symmetry and potential bias, (2) complementary evidence to address statistical limitations with small study counts, and (3) greater transparency to enhance reproducibility of conclusions, thereby strengthening the overall bias assessment in line with PRISMA guidelines.

• Line 99: Please define the abbreviation BMI.

• Line 100: Please clearly mention how the results of the meta-regression was interpreted and what measures were calculated for this purpose.

• Line 100: Please provide funnel plots for the leave-one-out sensitivity analyses.

• Line 103: Please provide a citation for the mentioned reference.

Results

• Line 113: Before reporting the meta-analysis results, it is necessary to systematically review the characteristics of the included studies, encompassing the overall included sample size, the sample size ranges, publication dates, countries of origin, study designs, measured outcomes, etc.

• Line 112-138: Please clearly mention how many studies and how many pregnancies were included in each meta-analysis.

Discussion

• Line 144: The authors only compared their findings with prior studies, while no interpretation was provided on how a history of CS can be associated with elevated uterine artery resistance in the current pregnancy. It is vital to discuss the potential pathophysiology behind this phenomenon.

• The discussion section appears underdeveloped, as evidenced by the limited number of references for a systematic review. This scarcity suggests insufficient engagement with the existing literature to adequately contextualize and interpret the findings. To strengthen the manuscript, the discussion should be expanded to: (1) incorporate more relevant studies to support key interpretations, (2) compare findings with previous meta-analyses on similar topics, and (3) address contradictory evidence in the literature. A more comprehensive discussion with additional references would enhance the scholarly rigor and provide readers with a better perspective on how these results advance current understanding.

Reviewer #2: General Comments:

The authors have done a commendable job in compiling and presenting the data. However, the manuscript would benefit from a thorough revision for grammar, sentence structure, and overall clarity to enhance readability and academic tone.

Introduction:

• Lines 50–51: Please provide a citation to support the statement.

• Line 57: Since multiple studies are referenced and no significant or negative outcomes are stated, more than one citation is needed to substantiate the claim.

Methods:

• Please define the abbreviations PRISMA and PROSPERO upon first use.

• Indicate the date on which the literature search was conducted.

• Line 78: Specify the version of the software which was used.

• When listing author contributions, include their initials in parentheses, e.g., (A.B. and C.D.).

• In the “Summary of Measures” section, clarify whether data extraction was performed by one or two researchers. Additionally, explain how discrepancies between reviewers were resolved.

• Since the results section includes a funnel plot, its use should also be described in the methods section.

Results:

• Clearly state the number of articles initially retrieved, how many were screened by title and abstract, how many underwent full-text review, and how many were ultimately included in the analysis.

• In the PRISMA flow diagram, one study is listed as coming from another source. Please clarify the origin of this study.

Discussion:

• Line 157: A citation is required to support the statement.

• The quality of evidence is typically evaluated using the GRADE tool. As your manuscript claims adherence to PRISMA guidelines, inclusion of GRADE assessment is recommended.

• Under limitations, it would be appropriate to mention the limited geographical generalizability of the findings, given that five studies were from Asia and one from Europe.

• Consider including the strengths of your study alongside the limitations.

• It would be beneficial to include recommendations for future research directions in the conclusion section.

Table 1:

• In Row 2, the reference appears in the middle of the author’s name. Please correct this.

Figure 1:

• Indicate how many results were retrieved from each database.

• Specify the reasons for exclusion and the number of studies excluded for each reason.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: Yes:  Mohammadamin Parsaei

Reviewer #2: No

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[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachments

Attachment

Submitted filename: Great job.docx

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Jun 18 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Mohammad Haddadi, M.D.

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Dear Authors,

Thank you for your efforts. Please address the following revisions:

1. Remove subheadings in the Introduction section.

2. Revise the Background of the Abstract. It should state the objective, not the results. For example, instead of "We included studies that reported…", write "We aimed to evaluate…".

3. Review grammar and spelling throughout the manuscript. For instance, clarify whether "PECO" is correctly used.

4. Ensure consistent use of abbreviations. For example, BMI is introduced as an abbreviation in line 116, but the full form appears again in line 133. Please revise for consistency.

5. Use a consistent form of English (either British or American) throughout the manuscript. For example, "Localized" in line 61 is American English, while "Analyses" in line 131 is British. Please standardize the language throughout.

6. Do not repeat the full form after defining an abbreviation. For instance, in lines 156–157, once PI and RI are defined, only use the abbreviations thereafter.

7. Move the 'Quality of the Evidence' section to the Results. It should be interpreted in the Discussion, not presented there as a result.

8. In Table 2, include the final score for each study and provide an interpretation guide in a footnote.

9. PRISMA diagram: In the final cell, specify the number of studies included in the systematic review and the meta-analysis—even if the numbers are the same.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: The comments have addressed my comments in a acceptable fashion. However, I recommend on the following modifications, before considering it for publication:

- Line 37: remove " to assess PI".

- Line 42: Lower your tone as the current evidence is really limited and further research in warranted.

- Line 72: E in PECO is for Exposure not Intervention

- Line 76: The exclusion criteria is not defined yet!

- Line 77: Please cite the main article for PRISMA 2020 (Page et al. 2021)

- Please use GRADEPro to make a solid table for your evidence certainty assessments.

Reviewer #2: In Line 72, the manuscript mischaracterizes the PECO model as being based on interventions; however, PECO is more appropriately used for observational studies and is structured around exposure rather than intervention. This should be corrected, and an appropriate citation supporting the use of the PECO framework should be added.

The study question is presented using the PECO format, but the individual components—Population, Exposure, Comparator, and Outcome—are not clearly defined. Each element should be explicitly stated to ensure clarity and methodological transparency.

The manuscript refers to the PRISMA guideline but does not provide a proper citation. A formal reference to the most current version of the PRISMA guideline (e.g., PRISMA 2020) should be included.

The phrase “including papers, published and unpublished thesis” is imprecise. It should be revised to clearly describe the types of literature included in the review, specifying the nature of the unpublished materials and the sources used to retrieve them.

The response to the earlier comment regarding the timing of the literature search is insufficient. The manuscript must explicitly indicate the date on which the literature search was conducted by your team for each database or platform. Merely referencing Line 83 is inadequate; the information should be clearly presented in the methods section.

As noted previously, the flow diagram in Figure 1 lacks specificity regarding exclusion criteria. The reasons for exclusion should be clearly stated both at the title and abstract screening stage and at the full-text review stage, in line with best practices for systematic review reporting.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: No

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org

Attachments

Attachment

Submitted filename: In Line 72.docx

A Comparative Systematic Review and Meta-Analysis of Uterine Artery Resistance in Pregnant Women with and Without Previous History of Cesarean Section

PONE-D-24-48119R2

Dear Dr. Chaichian,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager®  and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Mohammad Haddadi, MD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Thank you for your efforts. Well written and all comments are addressed.

Reviewers' comments: