Reviewer ’s report  
Title: A systematic review of methods to measure menstrual blood loss  
 
Version: 0 Date: 16 Apr 2018  
 
Reviewer: Sarah H. O'Brien  
 
Reviewer's report:  
Magnay and colleagues have performed a systematic review of the sensitivity and specificity of a 
variety of methods for  measuring menstrual blood loss. This is an important addition to the field 
that fills a gap in our scientific knowledge.  As the authors state, determining the heaviness of 
MBL is quite challenging both in the clinical and research arenas.  This paper wil l serve as a 
valuable resource to both clinicians, and investigators designing clinical trials in which MBL is 
an outcome. The paper is well written and nicely organized.  Table 1 and Table 2 are quite 
helpful, as are the examples of menstrual pictograms.  
 
One major comment is that in this reviewer's opinion the paper would be strengthened by 
including only studies in which the validation methods were either the alkaline hematin method 
or the weighed menstrual fluid method.  Despite the limitations of these  methods, as nicely 
outlined by the authors, these methods are the only ones actually measuring menstrual blood 
loss.  The inclusion of other studies seemed out of place, and the description of these studies 
were the only parts of the manuscript that I fou nd difficult to follow (Lines 259 -275).  This 
would only eliminate a few studies from Table 1.  For example, a study testing the sensitivity of 
the MIQ, using a validation of MIQ item 6c, or assessing the sensitivity of the PBAC by using 
the patients' subj ective assessment of menses as the gold standard, just don't seem to fit with the 
stated primary objective of the systematic review.  
 
One minor comment is to also include a figure of the PBAC.  While admittedly more familiar to 
readers than the pictograms,  I found myself pulling up an image online so that I could directly 
compare them more easily.  
 
Are the methods appropriate and well described?  
If not, 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 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 addition al statistical review is recommended, please speci fy 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  
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