Review for 10.1186/s12876-023-03036-3 (2023)

Title: Gastrointestinal Functioning and Menstrual Cycle Phase in Emerging Young Adult
Women: A Cross-Sectional Study
Version: 2 Date: 04 Aug 2023
Reviewer's report:
This well-written report describes the results of a cross-sectional, on-line  symptom survey of
some 600 first-year  female college students enrolled in a psychology course with the goal to
characterize the relationship between the menstrual cycle and GI symptoms using the well-
studied  PROMIS GI symptom scale and an investigator-developed (?) pain pictogram. A
health anxiety measure was used as a covariate. Although GI symptoms have demonstrated
exacerbations pre/peri menstrually among both "normal" volunteers and those with GI disorders
when using prospective daily menstrual symptom diaries (eg. see the NIH-funded studies of
Heitkemper et al), the role of health anxiety  as a contributor has not been well-studied, and the
abdominal pain scale/map is innovative. The investigators report no significant differences  in
PROMIS-GI scores across menstrual cycle groups, but health anxiety was a significant covariate
with each symptom  type and the abdominal pain ratings .At the same time, only  belly pain in
the hypogastric area  was higher during menses vs other phases.
These findings are interesting but the methods used raise several  issues which should be
addressed.
Perhaps the biggest concerns relate to: 1) the approach used to define and categorize survey
respondents into menstrual cycle phase groups, and 2)  the failure to use a longitudinal,
prospective design to study a dynamic, cyclic event.
In the intro the claim is made that the menstrual phase extends from day 1-day 8 with the
follicular phase extending from day 1-day 10. No references are provided and this implies that
the follicular phase extends only 2 days beyond menses.  Moreover, in several sections the
authors claim they used the same approach described in the study by Green and Green (2022),
but that report  is a systematic narrative review that critiques unfavorably the method used in
the current study. (single, crosssectional self-reported recall with no confirmation of ovulation
using biomarkers). The other paper by Draper et al is a prospective study at different time point
across the same cycle in the same individual using 4 hormones to define each phase. Then  an
additional approach is described using 7 day intervals for each phase according to other citations.
Please reconcile all these discrepanies, delete extraneous information,  and make clear which
references guided the categorization of menstrual phase groups .
A number of questions relate to the features of the study sample :
Clear inclusion/exclusion criteria should be presented. More demographic and reproductive
history information should be presented, preferably in a table 1,  that compares between those
with GI disorders and those without for such things as
age of menarche, length of menstrual cycles, duration of periods, BMI, history of dysmenorrhea
(painful menstrual cramps), current use of oral contraceptives, IUD, hormonal implants, history
of eating disorders - all factors that increase the risk of irregular cycles, amenorrhea, or
anovulation - and modify menstrual cycle complaints.
If these factors were not assessed or controlled for, please comment in the discussion on the
elevated risk of anovulation as a limitation in this sample of first-year college students where
stress, disordered eating, use of hormonal contraceptives are high.
In the analysis section, it is noted that women with longer cycles than 28 days (29-35) were
assigned to the premenstrual group, yet there is no mention of the fate of those with shorter
cycles (ie eg 22-25??) How were these treated?
Please describe the intake questions to determine menstrual cycle pattern. How were irregular
cycles defined?
Regarding the questionnaires;
The methods section should include a brief description of each questionnaire, its performance
and scores in other nonclinical female samples and the time frame recall (eg. in the last week?
month?). Although there are over 100 questions devoted to GI aproblems/disorders, the authors
gloss over the nature of the menstrual cycle questions, and there is no reference cited for the
PROMIS measure.
The methods notes there was "inconsistent responses for menses onset and end dates" Please
explain. How was menses end date determined and used in the data analysis?
In the discussion section, the observation is made that "we found that more than half of emerging
adult women presented with GI symptoms whose severity is greater than normative levels"
Please provide in the results section the data on mean scores for both the HA and PROMIS
questionnaires for all 4 study groups separated by clinical vs nonclinical samples..
Please eliminate all language relating to symptom "patterns" as this implies symptom changes
within the same individual. Finally the conclusions and implications for practice are somewhat
overreaching and should be softened given the simplistic design and failure to confirm
ovulation . One could argue that a lack of difference in GI symptoms among study groups  could
be attributed to  any number of confounds not controlled for in this preliminary study. There is
no mention of the need for future research on changes in PROMIS scores using a prospective,
multi-phase design across the same menstrual cycle in the same individual -  this is different
from studies of the "long-term relationship between menstrual phases and GI symptoms".