Reviewer’s report
Title: 
Comparison of levonorgestrel level and creamatocrit in milk following
immediate vs. delayed postpartum placement of the levonorgestrel IUD
Version: 
0 
Date: 
02 Jul 2020
Reviewer's report:
This is an interesting and important study but I have two concerns. 1- Please
clarify if the sample size was driven by the number of women who agreed to
participate in this substudy, or if there was any sample size calculation based on
the outcomes of levonorgestrel level in milk or crematocrit at either time point.
2- The importance of the significantly higher levonorgestrel level at 4-8 weeks in
the immediate postpartum group is not discussed or explored. What is the
potential meaning of this level for the infant's development or growth? The
conclusion as described (Overall, our study provides evidence that immediate
postpartum levonorgestrel IUD placement results in steady, low levels of
levonorgestrel in milk without significant effects on lipid content.) is not quite
accurate. It would be more transparent to state that the significance of the result
is not known. 
An additional limitation is that infant growth was not measured,
which could have provided reassurance and this should be included.
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Are the methods appropriate and well described?
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Yes
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authors.
Yes
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No
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I recommend additional statistical review
Quality of written English
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Acceptable
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