Reviewer ’s report  
 
Title: Factors Associated with Occupation Changes after Pregnancy/Delivery:  Result from 
Japan Environment & Children's Pi lot Study  
 
Version: 0 Date: 11 May 2017  
 
Reviewer: Janice F. Bell  
 
Reviewer's report:  
 
This is an interesting paper; however, there are several issues that could be addressed to 
strengthen its contribution to the women's health literature.  
1. The Background would be strengthened by including a rationale for the importance of thi s 
research to women's physical, social or psychological health. Other than mentioning the 
timing of women's participation in the labor force with respect to marriage, pregnancy and 
delivery there are not details about why this question is a women's health issue. As written, 
the introduction is presented from a demographic perspective without any supporting 
evidence for the women's health implications.  
 
2. More details are need to describe the study population from which the participants were 
drawn. Who part icipates in the JECS? (It is implied that all respondents are women and they 
"continued to work after pregnancy". ) Are JECS respondents recruited pre -conception, while 
pregnant or after birth? Did this study use data collected in the JECS or did the resea rchers 
send a separate survey to a subset of JECS participants? If so, how were these subjects 
identified? If I understood the methods correctly, the researchers sent a survey to a subset of 
JECS respondents at six time points. Why were only two time point s used for this work? 
What was the response rate to this survey?   
 
3. Including the rationale for the covariates selected would be useful. On the other hand, many 
important potential confounding variables were not addressed in the analysis (see comment 
below).  
 
4. Definitions for "Regular" and "non -regular" employees are required. In addition, this 
distinction --which appears as the primary conclusion of the study -- is not addressed in the 
background, making it difficult to follow the study through from its  purpose to its conclusion.  
 
5. There are several important limitations to this study that are not mentioned or discussed:  
 
a) The background supports examination of "participation" in the labor force in terms of 
working/not working. Yet the outcome was e xamined as binary changed/unchanged with the 
group "changing" occupation including those who resigned altogether. This limits the papers' 
contribution as it is unknown whether a change of occupation was to a more or less 
demanding job (e.g., what does a ch ange from clerical work to sales work actually mean? Is 
it the same as a change from sales work to clerical work?) -- moreover this "change" as 
measured includes not participating in the workforce at all.  
 
b) Many potential confounding variables are not me asured or considered --including 
socioeconomic status (household income, education, wealth).   
 
c) There is no discussion of selection bias in terms of survey participation and the possible 
implications for the study findings and generalization. This is diff icult to judge given the 
sparse information about the original cohort.  
 
d) There is no discussion of social desirability bias in terms of its effects on responses to the 
survey questions.   
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
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 require 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 manuscr ipt: 
 
Needs some language corrections before being published  
 
  
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, fund ing, 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 relating 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 interests?  
 
6. Do you have any non -financial com peting 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 that I have no completing 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 alon g 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 that any comments 
which I do  not wish to be included in my named repor t 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