PONE-D-25-23187Micronutrient Dynamics and Deficiency Risk Across Pregnancy and Postpartum in a Slovak CohortPLOS ONE

Dear Dr. Zilka,

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.

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We look forward to receiving your revised manuscript.

Kind regards,

Hansani Madushika Abeywickrama, Ph.D.

Academic Editor

PLOS ONE

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We thank Mumo Health for their generous support, which contributed to the execution of this study.

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We thank Mumo Health for their generous support, which contributed to the execution of this study.

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

6. 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 If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references.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 If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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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?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

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: Yes

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have produced a well-executed, methodologically sound, and highly relevant study. The manuscript contributes important findings to the field of maternal and public health nutrition, especially within the underrepresented Central European context.

The manuscript is technically sound and presents a rigorously designed cross-sectional cohort study that evaluates the fluctuations in key micronutrients (vitamins A, B6, B12, D, E, zinc, selenium, magnesium, transferrin, and homocysteine) across pregnancy and postpartum in a Slovak cohort.

The data collection methods—using both venous blood and dried blood spot (DBS) sampling—are scientifically appropriate and well-described, and the conclusions are well-supported by the data.

The statistical analysis is robust and suitable for the cross-sectional study design.

With regards to data availability policy, the authors confirm that all data are fully available without restriction. The manuscript explicitly states this and includes detailed tables (e.g., Table 1 and Table 2) listing descriptive statistics, prevalence rates, and reference ranges.

Regarding presentation of the manuscript, the manuscript is clearly written and well-organized, with logical flow between sections.

Overall, the study have some major strengths which include;

a) Comprehensive assessment of 10 micronutrients during pregnancy and postpartum.

b) First-time comparison of DBS and venous blood measurements in a Slovak population.

c) Statistically sound and thoroughly interpreted results.

d) Strong public health implications for antenatal and postpartum care.

However, there are some areas with minor suggestions which include;

a) Consider briefly noting the implications of the study's urban clinical setting and its potential limitation for generalizability to rural populations.

b) A dedicated "Limitations" paragraph would enhance the transparency of the discussion.

c) A minor grammar and syntax check will improve overall readability.

Reviewer #2: This paper is one of the most current papers highlighting the micronutrient deficiency during various important periods as well as the use of DBS as the alternative less-invasive method. This paper is also written well. Some minor improvements are necessary.

1. Line 149, lines 187-188: The subheading is not suitable for the content. The paragraph mentioned the results of all nutrients, not only the nutrients at the subheading. It is suggested to use a more general subheading.

2. Line 426 Table 1: There is no footnote for the two asterisks.

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Reviewer #1: Yes:  Chibuzor Stella Amadi

Reviewer #2: No

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PONE-D-25-23187R1Micronutrient Dynamics and Deficiency Risk Across Pregnancy and Postpartum in a Slovak CohortPLOS ONE

Dear Dr. Zilka,

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 Sep 05 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.

Please include the following items when submitting your revised manuscript:

• 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.

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,

Hansani Madushika Abeywickrama, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

1. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

2. 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:

Please respond to the comments raised by comment 3.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: (No Response)

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

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

Reviewer #3: Yes

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

Reviewer #2: Yes

Reviewer #3: Yes

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

Reviewer #3: Yes

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #3: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

Reviewer #3: The authors have submitted a valuable and timely manuscript that offers important insight into the micronutrient profiles of pregnant and postpartum women in Slovakia. The study is highly relevant to the fields of maternal-fetal medicine, clinical nutrition, and public health. The novelty lies in both the trimester-specific profiling of ten micronutrients and the evaluation of dried blood spot (DBS) sampling as a minimally invasive, scalable diagnostic method.

This research addresses a critical knowledge gap in the European context, where population-based data on pregnancy-specific nutrient dynamics are scarce. The inclusion of age-matched non-pregnant controls, the use of clinically validated assays, and the analysis of both venous and capillary samples contribute to the strength and originality of the manuscript. The findings have the potential to inform prenatal care practices and guide nutritional policy recommendations.

The manuscript is technically sound. It follows a cross-sectional design with clearly defined eligibility criteria and applies a standardized protocol for sampling and nutrient analysis. The statistical approach is appropriate, employing linear regression, Spearman partial correlations, and post hoc testing with Holm corrections. The authors correctly adjusted for multiple comparisons and applied heteroskedasticity consistent variance estimators, which strengthen the validity of their results. The results support the authors’ conclusions that several micronutrients including vitamin A, B12, zinc, and homocysteine exhibit significant physiological variation across pregnancy stages and the postpartum period.

Regarding statistical analysis, all models are appropriate for the study design. However, additional reporting of assumptions (e.g., normality, variance homogeneity) and inclusion of effect sizes and confidence intervals would improve interpretability. Furthermore, it would be helpful to clarify whether key confounders such as BMI, parity, or supplement use were considered in the models, as these may significantly influence nutrient levels. For data availability, the current statement that data are “fully available without restriction” with DOI included complies with PLOS ONE policy.

With respect to presentation, the manuscript is well-organized and written in clear, academic English. The structure adheres to standard scientific conventions. There are a few minor issues with phrasing and grammar (e.g., repetition in “Ethics Committee Ethics Committee” and long, complex sentences in the Discussion section) that should be corrected during final revision.

Suggestions for Improvement:

1.Clearly state whether supplement use, BMI, or parity were included as covariates or excluded from statistical analysis.

2. Conduct a light language edit to address grammatical inconsistencies and remove redundancy.

3. Avoid causal terms like “decline” or “increase” since the study is cross-sectional. Instead, say “lower levels observed in group X” or “group differences.”

In summary, this is a well-designed, clinically relevant study that offers new insight into nutritional challenges during pregnancy in Europe. With modest revisions and improved clarity around data transparency and modeling assumptions, the manuscript will be a strong candidate for publication in PLOS ONE.

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7. PLOS authors have the option to publish the peer review history of their article (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 #2: No

Reviewer #3: Yes:  Chinwendu Ubani

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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.

Micronutrient Dynamics and Deficiency Risk Across Pregnancy and Postpartum in a Slovak Cohort

PONE-D-25-23187R2

Dear Dr. Zilka,

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.

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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,

Hansani Madushika Abeywickrama, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: All comments have been addressed

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

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: (No Response)

Reviewer #3: Yes

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

Reviewer #2: (No Response)

Reviewer #3: (No Response)

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: (No Response)

Reviewer #3: Yes

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

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: (No Response)

Reviewer #3: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

Reviewer #3: The authors have made substantial improvements to the manuscript, resulting in a well-structured and scientifically sound paper. The study design and rationale are now communicated with greater clarity, and the data analysis methods have been presented in a manner that demonstrates rigor and appropriateness for the research objectives.

A key strength of this revised manuscript lies in its transparent explanation for the exclusion of certain variables specifically BMI, supplement use, and parity. The justification provided is both logical and clearly articulated, reflecting thoughtful consideration of data quality, consistency, and methodological relevance. This enhances the credibility of the analysis.

The authors have also appropriately revised the language throughout the manuscript to remove any causal implications, adopting observational descriptors that align with the cross-sectional nature of the study. This shift improves the scientific integrity and interpretability of the findings.

Importantly, the justification for the use of dried blood spot (DBS) sampling is compelling. The authors explain its practicality, accessibility, and comparability to venous sampling with clarity, supporting its relevance for both clinical settings and population-level monitoring. This methodological approach significantly strengthens the study’s clinical applicability.

Finally, the manuscript addresses a critical data gap in maternal nutrition surveillance in Central Europe. The findings contribute valuable insight into micronutrient trends during pregnancy and postpartum an area with limited region-specific evidence. The work stands to inform future public health strategies and nutritional interventions in similar contexts.

Overall, the manuscript is now well-prepared for publication and represents a meaningful contribution to maternal health research.

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7. PLOS authors have the option to publish the peer review history of their article (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 #2: No

Reviewer #3: Yes:  Chinwendu Ubani

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