Reviewer ’s report  
 
Title: A preliminary evaluation of influence of body mass index on in vitro fertilization outcome  
in non -obese endometriosis patients. An observational cross -sectional study  
 
Version: 0 Date: 25 Mar 2017  
 
Reviewer: Jesus Salvador Jiménez López  
 
Reviewer's report:  
 
"A preliminary evaluation of the influence of body mass index on in vitro fertilization outcome 
in non -obese endometriosis patients. An observational cross -sectional study ".  
 
 
Title : 
Suitable. Explain the objective and indicate the type of study performed.  
 
Abstract: The way of exposing the justifications that lead to the hypothesis of the present article 
is somewhat confused. We would recommend revising the wording of this section ( lines 27 -34). 
The rest of the content is adequate, presents correctly and concisely the method, main objectives 
and results as well as a brief conclusion.  
 
Background: In this section the explanations that lead to the development of the hypothesis are 
more  adequate, although the clinical utility of the hypothesis is not considered (we will deal with 
this aspect in discussion and conclusions).  
 
Methods:  
Regarding endometriosis:  
- According to the authors, this was carried out laparoscopically according to the 
classification of the American Society for Reproductive Medicine (classification of 
endometriosis: 1996) (lines 101 -105). In this same review, it is considered that in order  to 
establish the diagnosis of endometriosis, a series of criteria must be fulfilled which we 
consider necessary both to be named in the article and to specify which ones were 
fulfilled in their patients (see: histological diagnosis or: Size of cysts <12cm , adhesions 
between cyst and pelvic wall / wide ligament, endometriosis on ovarian surface, 
chocolate content of cysts). Table 2 only shows the degree of endometriosis (they have 
not calculated percentages in patient with normo and overweight) and whether or not 
there were endometriomas.  
- They report that the reason for subjecting these patients to surgery was either the 
diagnosis of infertility or the clinical / ultrasound suspicion of endometriosis in patients 
with a history of infertility (lines 106 -108). It is not specified whether the time of 
infertility elapsed prior to surgery or its temporal relation to the intervention. It is also not 
known whether they had undergone previous cycles of IVF before confirming 
endometriosis. It is assumed in the same way that the diagnosis of endometriosis was 
established in the context of infertility, and that therefore they did not receive medical 
treatment for this pathology, although this data does not appear either.  
- Being aware of the compromise involved in comp romising the ovarian reserve with the 
surgical manipulation of the appendages, exclude those patients who were submitted to it 
for reasons beyond the control of endometriosis. However, a cystostomy in the context of 
an endometriosis would hypothetically re act in the same way as for another cause. We 
therefore consider that it could be a bias. Determining prior to and following the same 
parameters such as baseline levels of E2 and FSH, antimullerian hormone and count of 
antral follicles could throw informati on on this and support his theory exposed in lines 
382-384. 
Regarding the IVF cycle:  
There are no grounds for using GnRH agonists or antagonists (lines 227 -228).  
The quality of the transferred embryos is not known, a fact that clearly influences the result s of 
the cycle.  
 
 
Results:  
They are properly described in the text and presentation in tables (except error in table 2 already 
mentioned).  
 
Discussion:  
The discussion is well written and properly ordered. It establishes clearly the conclusions, 
although it  is important to make an appreciation about the clinical utility of the same. Based on 
the hypothesis of their hypothesis, they should demonstrate that changes in BMI lead to changes 
in the severity of endometriosis and therefore in the results of the assi sted reproduction 
technique; The objective of the analysis should be directed to the normopeso leads to a greater 
success of the same, in order to advise the patient, and not to do so through overweight.  
Are the methods appropriate and well described?  
If no t, 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 t he data shown?  
If not, please explain in your comments to the authors.  
 
Unable to assess  
 
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, ple ase 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:  
 
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 publi cation 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 curr ently 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 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 g ive details below.  
 
I declare that I have no competing interests  
 
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