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: 
26 Jul 2020
Reviewer's report:
Thank you for the opportunity to review this manuscript. Better understanding
immediate LARC provision and its effects on breastfeeding is of great
importance. While this paper reports on a small pilot sample with physiologic
and not patient-oriented data, it provides baseline data for future research about
breastfeeding after immediate postpartum levonorgestrel IUD insertion. I believe
it will be of interest to readers of this journal. I have some recommendations to
strengthen the paper prior to publication. 
In particular, I recommend that some work is done to better explain the
usefulness and limitations of both levonorgestrel testing in breastmilk and
creamatocrit, neither of which is explained until the discussion.
Abstract
I would suggest clarifying in the abstract that the data presented is from 22
participants, not 32. 
The results section of the abstract did not make sense to me until I read through
the discussion of the manuscript, which explained that levonorgestrel was found
in breastmilk participants prior to IUD insertion. 
Introduction
Please include here what is known about creamatocrit in breastmilk and its
association, if any, with breastfeeding outcomes. The information in the methods
can be moved here along with the 1978 reference, but we also need to know
about any association with patient-oriented outcomes such as infant health so
that the reader can decide the appropriateness of creamatocrit as an outcome
measure. What constitutes a healthy vs unhealthy value?
Please also include here what is known about exogenous progestin content in
breastmilk, and levonorgestrel in breastmilk in particular. It is surprising as a
reader to find out about the positive levonorgestrel levels in the delayed group,
as I assumed that this is an outcome included in other studies. Has this
commercially-available immunoassay not been used for this before?
Both of these things will further make the case that a pilot is needed to establish
baseline data for future work.
Methods
Please state specifically that this pilot was not powered to find a difference in
creamatocrit levels. Why did you decide on 12 participants for each group?
Line 135: There is no section 2.5.
Discussion
Lines 143-144: This is understated and I recommend rewording it. Actually,
most, not some, of the participants in the delayed group had levonorgestrel in
their initial milk sample. Going by your IQR values, a quarter of your delayed
participants had a higher levonorgestrel levels than a quarter of your immediate
participants. Is there a way you can further support your assessment that this is
considered a "trace" amount of levonorgestrel? Is this the amount that you were
expecting? Are there breastmilk levonorgestrel levels from users of other
levonorgestrel products that you can compare these findings to?
Line 155: Was this not included in the consent form? Was it included as
optional?
Thank you again for the opportunity to review this manuscript.
Publons Reviewer Recognition
. Springer Nature can send verification of this
review directly to Publons (a subsidiary of Clarivate Analytics). If you would
like to take advantage of this service, please click on the “Yes” option below.
Your name, email address, title of the reviewed manuscript, name of the journal,
and date of your review submission (the “Review Data”) will then be transmitted
to Publons upon publication of the manuscript. If you have already registered at
Publons, they will notify you of the receipt of this review and update your profile
as per your settings and their policy. If you are not registered with Publons, you
will receive an email from them asking you to register in order for them to be
able to recognize your review on your new profile page. Publons may use the
Review Data to generate derivative metadata for the benefit of Publons and you
as a reviewer, carefully considering the sensitivity of such information. For
example, Publons may verify your record as a reviewer by updating your profile
published on its webservice if you have registered for such service or help
editors to identify candidate reviewers. Please find the details of processing in
Publons’ privacy policy 
https://publons.com/about/terms
No
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 publication 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 currently 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.
Reviewer Publication Consent.
 I agree for my report to be made available
under an Open Access Creative Commons CC-BY License (
http://creativecommons.org/licenses/by/4.0
) if this manuscript is accepted for
publication. Any comments that I do not wish to be included in the published
report have been included as confidential comments to the editor, which will not
be published.
If you are not happy for us to publish this report, please contact the editorial
office before completing the review.
If you wish, you can include your name in your published report. Please note
you must decide whether to include your name at the start of the process and
confirm this decision whenever prompted. If you change your decision later, we
will not be able to publish your name.
I agree to the terms of the CC-BY 4.0 license; please 
do not
 publish my name
with my report. (default)
Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes