Reviewer ’s report  
 
Title: Impact of preconceptional micronutrient supple mentation on maternal mental health 
during pregnancy and postpartum: Results from a randomized controlled trial in Vietnam  
 
Version: 0 Date: 29 Dec 2016  
 
Reviewer: Nisreen Alwan  
 
Reviewer's report:  
 
This is an interesting paper tackling an important research question. However, there is confusion 
in the reporting of outcomes.  
In the methods section, you state that MDS is defined as EPDS score of more than 4. However in 
the results section, you report a mean and a standard deviation for MDS (line 194). Then you go 
back and report it as a binary variable 'the prevalence of elevated MD S ...' (line 196).  
I am not convinced with the concept that CES -D score is an effect modifier. Surely there is 
significant collinearity with the outcome variable (EPDS). It is reasonable to stratify the analysis 
by baseline CES -D score tertiles, but it is  better to call it as such -stratification or subgroup 
analysis - rather than effect modification. I see not role for testing for statistical interaction here. 
You also have not provided a table of results for your interaction analysis to try and make sens e 
of it. If you base your conclusion on the results from your stratified analyses then these should be 
illustrated in detail in the paper.  
Are the methods appropriate 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 conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects requ ire further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
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 future?  
 
3. Do you hold or are you currently applying for any patents re lating to the content of the  
manuscript?  
 
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 intere sts? 
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I declare tha t I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand t hat any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal