Reviewer ’s report  
 
Title: Effects of oral contraceptives and natural menstrual cycling on  environmental learning  
 
Version: 1 Date: 15 Jun 2018  
 
Reviewer: MARIE -FRANCE MARIN  
 
Reviewer's report:  
 
The authors have done a great job at addressing the different c omments. In my opinion, the 
manuscript has been improved considerably.  
 
 
 
I still have some points that I believe should be addressed.  
 
1) In the graphs of memory performance, it would be important to label the axes.  
 
 
2) The authors found no group differences at delayed recall - when looking at the graph - it 
looks like the performance is maximized in both groups (ceiling effect). This should be 
discussed in the limitations sections - it is unclear whether a more comple x (which would 
allow a greater variability in the results) would produce similar results.  
 
 
3) The discussion about cortisol and stress responsivity differences remains poorly 
connected to the text. Given that the current study did not use stress inductio n protocols, 
they need to make a better connexion as to why the study on cortisol and stress reactivity 
is in line with their findings. Are they inferring that their task and/or testing procedures 
were stressful? Or are they referring to different basal co rtisol levels in their groups? It is 
very vague and needs further clarification.  
 
 
4) The discussion is very brief and some results should be further discussed. For example, 
the authors discuss about the distribution of receptors in brain regions involved i n 
learning and memory and how the pill might affect some of these processes. However, 
the reasons why the between -group differences emerge during encoding (learning) and 
not during the delayed memory test should be further discussed. There is one sentence 
mentioning that memory formation and recall is a complex process. First, this sentence 
should be nuanced given that memory formation and memory recall are two distinct 
cognitive processes. And from there, the authors should differentiate these processes an d 
also expand with regards to the differences found in learning, but not when tester after a 
delay.  
 
 
5) The authors now acknowledge the absence of men group as a limitation. They do 
however mention that it is well -known that men outperform women for topog raphical 
memory tasks. Have these studies compared NCW to men or women taking oral 
contraceptives? This should be mentioned and discussed. In the current manuscript, the 
authors find a difference in learning, with women on OC outperforming NCW - it would 
be interesting to see whether men would have similar performance to OC women or 
would still outperform OC women.  
 
 
 
Are the methods appropriate and well described?  
If not, p lease 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.  
 
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:  
 
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, f ees, 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 t hat 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 give details below.  
 
I declare that I have no competing interests  
 
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