Reviewer ’s report  
 
Title: Relationship between caffeine intake and infertility: a systematic review of controlled  
clinical studies  
 
Version : 1 Date: 17 Apr 2020  
 
Reviewer: Mahmut Kuntay Kokanali  
 
Reviewer's report:  
 
An interesting and well written review on a subject that is difficult to evaluate. It includes a 
limited number of retrospective studies, and therefore raises a number of bias about coffee 
dosage standardization and evaluation of other possible factors. Th erefore, the reliability of the 
findings is unclear. However, the authors stressed the existence of all these limitations. I believe 
that this is a well -prepared review in order to raise awareness on this issue. And also, I believe 
that adding an extra wil l not change the results much. I think it is suitable to be published.  
 
Are the methods appr opriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusio ns drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical revie w is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain  or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the fut ure? 
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
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4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of  the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
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below.  If your reply is yes to any, please give details below.  
 
I declare that I have no competing interest.  
 
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I agree to the open peer review policy of the journal