Review for 10.1186/s12876-020-1182-y (2020)

Reviewer’s report
Title: Intake of dairy protein during pregnancy in IBD and risk of SGA in a Norwegian
population-based Mother and Child cohort
Version: 0 Date: 08 Sep 2019
Reviewer: Jimil Shah
Reviewer's report:
My comments: 
1. In methodology, it has been mentioned that three questioners were mailed to the pregnant patients,
however, details and timing of third questioners has not been provided.
2. Questioners 2 (Q2) (FFQ) was introduced in 2002. However, patient enrollment was from 1999 to
2008. Kindly give data of Q2 which was used for patients enrolled from 1999 to 2002.
3. Data regarding IBD activity was recorded in 2013 based on patients recall of disease activity.
Authors have included this limitation in the manuscript. However, it looks like a major flaw in the
methodology. IBD is a relapsing remitting disease, patients with active disease usually have many
flares of disease activity. So, reliability of patient's recall regarding disease activity 5-13 years back is
highly questionable. Moreover, if at all authors wanted to add this aspect in their manuscript, they
should have reviewed all medical records, prescription details and hospital admission records rather
than relying on patients recall ability. 
4. In table 3, 4 and 5, authors have classified PPDS groups in group 1,2 and 3. However, they have not
provided any description of classification of these groups in methodology. 
5. Kindly provide more detailed and descriptive legends of figures. 
6. In table number 4, data of 341 patients of IBD has been provided. However, in starting of study it
has been mentioned that total of 342 patients were enrolled in the study.
7.  In  results  section,  association  between  PPDS  and  risk  of  SGA is  very  complicated  and  less
comprehensible. Though authors have used four different models for this association, the final message
is not clear.
8. In conclusion, authors have mentioned that lactose intolerance might coexist frequently with IBD
which may cause of diarrhea and SGA. However, authors have not studied either of the factor in their
article. Authors should have drawn conclusion based on their study finding. 
9. Authors may reduce the length of discussion and make it more readable. 
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 manuscript:
Needs some language corrections before being published
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