Title: Establishment and validation of a simple nomogram for predicting early postpartum stress
urinary incontinence among women with vaginal delivery: A retrospective study
Version: 1 Date: 14 Dec 2022
Reviewer's report:
Comments on “Establishment and validation of a simple nomogram for predicting early
postpartum stress urinary incontinence among women with vaginal delivery: A retrospective
study’
In this manuscript, the authors attempt to establish and validate a nomogram for predicting early
post-partum SUI in women who undergo a vaginal delivery.
They included age, parity, second stage of labor, infant weight and forceps delivery into the
nomogram which allows for quantification of risk of postpartum SUI.
It is important to note that many studies have been published on this similar topic, using similar
methodology and it is unclear as to what the current study adds to the existing literature.
Also, not sure how this study is relevant to the readership of the BMC given that it is done in
only an Asian population. I would recommend against publication.
Abstract:
1. Please describe the study population, the factors which were extracted/evaluated and the
primary outcome in the abstract.
2. The authors conclude that the model might contribute to early identification of postpartum
SUI when it only helps quantify their risk of developing SUI
Introduction
1. The authors should state their hypothesis in the last paragraph of the introduction.
2. Line 3 : SUI is not the most common pattern of UI, as the most common type of UI differs
with different age groups.
3. Why did the authors not include relevant factors like smoking history, pre pregnancy/intra
pregnancy SUI, breast feeding, mode of delivery for prior parity which are well known risks
for SUI?
Methods:
4. Is there a specific reason why those specific time periods were utilized (other than COVID
pandemic) for inclusion in the training and validation cohorts?
5. Were patients with prior history of SUI or development of SUI during pregnancy excluded
from the study? If yes, this needs to be mentioned. Was any screening for the same performed at
the time of diagnosis of pregnancy / during prenatal visits? This is specifically important because
a prior published study found that SUI during pregnancy was the most valuable predictor of SUI
postpartum. (Chen at al. https://pubmed.ncbi.nlm.nih.gov/32756060/)
6. When authors mention that patients with history of cesarean delivery were excluded does
that mean patients who underwent a cesarean delivery during the study period OR does it mean
any prior history of cesarean delivery in the women’s lifetime? Furthermore, does it mean that
patients who underwent a successful vaginal birth after cesarean were excluded from the study?
7. Please explain what ‘uncleaned lochia’ entails. Also, please clarify what the ‘etc’ in the
exclusion criteria entails.
8. Line 22: How do the authors hypothesize that their nomogram will prevent occurrence of SUI
when it can only help quantify the risk of developing SUI?
9. Authors should compare the baseline characteristics (Age, parity, BMI at minimum) of the
excluded patients to those included in order to understand the applicability of the nomogram.
10. The authors need to provide an explicit definition of their primary outcome. Was it
development of new SUI? Was that determined just by the answer Yes/No on the ICIQ-UI-SF?
Was baseline SUI assessed prior to delivery?
11. How was the information extracted using medical records? Were ICD 9 and 10 codes used?
Results
12. There is a discrepancy in the number of people excluded and included in the study which
needs to be addressed.
Firstly, if 7033 women were delivered in the study period, and 3980 women were excluded,
then ,7033-3980 = 3053 should be included in the study (and not 3051).
Secondly, 3580+153+16+43+118 = 3910. However, the authors report 3980 women were
excluded. Also, the authors mention that 118 were excluded with missing data, but the consort
diagram depicts that 43 were excluded with missing data.
Please clarify.
13. Line 13: The authors report they include instrumental birth in the model however they have
not reported on vacuum deliveries. Why was data not collected on the occurrence of vacuum
assisted deliveries? Instrumental birth needs to be rephrased as forceps deliveries or the methods
need to clarify how instrumented delivery was defined and captured, then results reported.
Discussion
14. Line 2: I would rephrase to ‘ ..quantify the risks of developing SUI in the early postpartum
period’.
15. Line 4 : The line ‘’ Early rehabilitation is of critical importance for prevention of progression
and persistence of SUI ‘’ warrants a reference
16. Line 15: I recommend rephrasing to ‘increase the risk of SUI’ instead of UI.
17. The authors should acknowledge the lack of objective measurements for determining SUI
such as cough stress test, pad test, urodynamic testing as a limitation of the study
18.  The authors need to acknowledge the limitation of having a short postpartum duration and
follow up duration for determining risk of SUI. It is well known that C-index decreases with an
increase in follow up duration. They should also acknowledge the limitation that they have only
determined the incidence of SUI, and not the duration or severity of the same.
19. Furthermore, they also need to acknowledge that they did not include baseline SUI symptoms
or breastfeeding as a variable. Breastfeeding can affect the hormonal milieu which can affect
tissue laxity and thus the development of postpartum SUI
20. Line 15 : I would caution the authors to report that this is the first nomogram to predict
occurrence of SUI. There have been multiple studies published in this arena in the recent year,
and as early as 2013 (Jelovsek et al- https://pubmed.ncbi.nlm.nih.gov/23442509/)
21. How will the authors plan on further increasing the applicability and generalizability of this
nomogram.