Reviewer ’s report  
 
Title: Serum 25 hydroxyvitamin D levels and affecting factors among preconception fertile  
women  
 
Version: 0 Date: 21 Oct 2019  
 
Reviewer: Carol L Wagner  
 
Reviewer's report:  
 
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This is an interesting manuscript that chronicles the vitamin D status of 410 women who sought 
preconception genetic counseling at a clinic in China. The investigators found significant 
deficiency in this cross -sectional study of women, which has implications for later pregnancy 
outcomes. That younger women and women who were working outside of the home had the 
highest risk were notable findings of the study, and suggest that public health initiatives should be 
encouraged to improve the vitamin D status of these women as part of preconception counseling. 
These findings are consistent with other findings throughout  the world, but the significance of 
these findings in the context of conception and pregnancy outcomes is not addressed, and would 
add merit to this study. Elaboration about when conception occurred after the preconception 
consult was performed would be he lpful.  
 
The following are questions and certain changes that if addressed would improve the rigor and 
readability of this manuscript.  
 
(1) Abstract, Line 22: it's is a contraction and means it is; you want to use the possessive "its". 
Please correct.  
 
(2) Introduction, lines 33 -39: "Women usually neglect their vitamin D inadequacy due not to feel 
uncomfortable." It is unclear what is meant by this sentence. Please rewrite it to improve clarity.  
 
(3) Introduction, lines 56 -59: "...for women planning recent p regnancy concerning their need of 
vitamin D supplementation...": this sentence is awkward and unclear. Please rewrite.  
 
(4) Materials and Methods, line 8: "recruited the cross -sectional" should be changed to "recruited 
in this cross -sectional..."  
 
(5) Mate rials and Methods: Measurement of vitamin D: please specify the interassay variability.  
 
(6) Materials and Methods: It is unclear how many women seen during the preconception period 
became pregnant? Did they all become pregnant? How long had the women been  trying to become 
pregnant? Was there a difference in pregnancy rates over time as a function of vitamin D status?  
 
(7) Materials and Methods, Statistical Analysis: data that was normally distributed: unless you had 
a single data point, the word "data" is plural so the sentence should be changed to "Data that were 
normally distributed..."  
 
(8) Results: "Distributions of  general characteristics among participant women": should be 
changed to "General Characteristics of Participant Women"  
 
(9) Results, line 46: reported having one or more, not "reported having a or more."  
 
(10) Results, lines 12 -15: It is unclear what is me ant by "had inadequate concentrations for multiple 
health."  
 
(11) Table 2: Change "No -Working to "Non -Working."  
 
(12) Figure 1: the n's of participants for each month should be listed.  
 
(13) Discussion: Lines 36 -39: it is not really clear how you knew the women would become 
pregnant and the characteristics of when the women became pregnant should be recorded.  
 
(14) Discussion, next page, line 7: "This is alarming as these are pregnant in following 3 -6 
months." This sentence is awkward and needs to be rewrit ten. In addition, there is no mention of 
how this is known and the characteristics of the pregnancy, etc. Since this is stressed as an 
important aspect of the study, it should be expanded.  
 
(15) Discussion, lines 34 -39: "Among the occupations considered in  the present study, the women 
almost were office -based workers..." This sentence needs to be rewritten. I am assuming that you 
meant: "Among the occupations of those women participating in this study, those women who 
were office -based had a greater risk of  vitamin D deficiency compared to women who were not 
office -based workers." Or something like that.  
 
(16) Discussion, next page, lines 1 -5: "Similar to the results that traveling to a warmer climate 
during winter/spring..." this is a phrase and not a compl ete sentence; the verb is missing.  
 
(17) Discussion, line 56, Limitations paragraph: change "insight on longitudinal changes" to 
"insight into longitudinal changes."  
 
(18) References #16: the names are given in the incorrect order: the last should be liste d first 
followed by the first and middle initial(s), which is the format of the other references.  
 
 
 
 
 
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.  
 
Yes 
 
Are you able to assess any statistics in the manus cript 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 manuscript:  
 
Needs some l anguage 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, funding, or salary fr om an 
organisation that may in any way gain or lose financial ly from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat may in any way gain or lose 
financially from the publication o f 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 app lied 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?  
 
If you can answer no to all of the above, write 'I declare t hat I have no competing interests' below.  
If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
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