PONE-D-19-30288

Recurrence rate of preterm birth and associated factors among women who delivered at Kilimanjaro Christian Medical centre in Northern Tanzania: a registry based cohort study

PLOS ONE

Dear Dr. Kalengo,

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Joel Msafiri Francis, MD, MS, PhD

Academic Editor

PLOS ONE

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Additional Editor Comments (if provided):

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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: Partly

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: 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

Reviewer #3: No

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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

Reviewer #3: 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: Preterm birth is an important medical problem needing academic efforts. This work was very well done, however, I did not learn anything by reading the manuscript. All the results are as expected and no new discovery would benefit the research and management of preterm birth. It is not challenging academically, therefore, I suggest the rejection of the work.

Reviewer #2: Overall:

It’s an important study as preterm labour and delivery is an important cause of perinatal deaths and long term complications in the newborns. This information will benefit the studied community as the gained information will be used in managing future pregnancies of patients in this locality and Tanzania in general.

General comment:

There are few grammatical errors which need to be corrected.

Title: Well written, clear, and in line with the objectives. It explains what has been researched.

Abstract: The abstract is provided and it contains all the important elements of the study.

Introduction:

The subject has been well researched. There is mixed information about the concept of risk and recurrence in second and third paragraphs, which I feel should be separated.

Last but one paragraph shows that the “study will be done”. This needs to be written in past tense.

Methods:

The methods have been explained, and have provided answers to raised questions, but do not explain whether this was a prospective or retrospective study. This could explain the data that was missing.

The category for the late preterm birth as explained it the first paragraph of variable definitions is “<37 weeks of gestation age, which means 36 completed weeks. This means there are women who were missed who were in the 37th week and had not attained 37 completed weeks

Ethical considerations:

It was ethical to carry out this study as it caused no reported harm to the participants.

Ethical issues were well treated as women gave informed consent, even though it is not explained whether there were women who did not give consent and what happened to them.

Results:

The results section is provided, and explains the results well.

There is too much text that explains the results while the tables are provided. The narrative part can concentrate on highlighting only important findings in the table.

Some sentences are not very clear, and few are hanging.

Discussion:

This is provided and has discussed the results of their study but it does not discuss very well the results and link them well with other previous studies.

Conclusion:

Conclusions have been given. It’s important to limit the conclusions to only what has been studied.

Reviewer #3: Thank you for the opportunity to review this manuscript of an important topic in low income country setting.

Here are my comments to improve the manuscript.

ABSTRACT:

The conclusion misses some of the important variables that were significant Need to mention the numerous factors associated with the recurrence.

INTRODUCTION

Please put the long form of KCMC on page 4 paragraph 1 because it is used for the first time.

Write Sustainable Development Goals and not sustainable development goals on page 4 paragraph 2

METHODOLOGY

Study population and study sample: It is good practice to show power calculation to see whether the sample size in the database is enough to depict the outcome intended.

Why were the referred cases with medical complications from rural area excluded. Some could have been referred due to conditions that needed medically induced delivery in a tertiary institution.

Variable definitions: There are other important conditions associated with PTb such as diabetes mellitus, chronic hypertension. But these were not factored in. Can you explain if these conditions are not captured in the database.

Data Analysis: You should add a description about risk ratio in the text.

Ethical considerations: Write long form for KCMUCo

RESULTS

Page 6 last paragraph:"Through spontaneous vaginal delivery (68.15%)". This sentence is hanging it is not clear.

Table 1: Please check the age range 15 -25 and 25 -35. It seems 25 years are included into the two groups which is misleading in my opinion

Table2: Please rearrange the IPI starting with <24 then 24-29 etc. On parity how do you have primigravida if the inclusion criteria was two or more singleton deliveries: The number of antenatal visits: what about those with four visits it seems they are missing here.

Table 3: A bit confusing as the row numbers add more than the total. May be you need to remove the column with TOTAL N.

Recurrence of preterm birth ; I would suggest you put a numerator and denominator for there overall recurrent rate of 24.4% as it not very clear from table 3.

DISCUSSION

Page 8 last paragraph:Why do you think it has increased. Is because of referral cases or because of the population increase or because of increase in medically induced deliveries?

Pg 9 Paragraph 1. You can not really make comparison using the meta analysis in my opinion. Rather may be look at the individual papers in meta analysis to make a comparison.

Pg 9 Paragraph 3:For the medically indicated preterm of 44.6%, Probably should say that for medically induced, preterm care should be improved to make sure the premature babies are taken care properly rather than need to be avoided as you can not avoid if delivery is indicated before term.

Paragraph 3 page 10: I think family planning is important but those with long IPI probably were using FP or thee was delay because of other reasons. I think here what is important is to educate the women on the risks of long IPI on preterm birth during the antenatal period.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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Recurrence rate of preterm birth and associated factors among women who delivered at Kilimanjaro Christian Medical centre in Northern Tanzania: a registry based cohort study

PONE-D-19-30288R1

Dear Dr. Kalengo,

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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Kind regards,

Joel Msafiri Francis, MD, MS, PhD

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: 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: (No Response)

Reviewer #3: No

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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: (No Response)

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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: Furaha August