Table 4.

General research considerations

Consideration	Rationale (intended to…)	Pros (could…)	Cons (could…)
Employ a single-blind design; although participants cannot be blinded, the researcher can be blind to the intended testing timepoint	Protect against bias	Reduce unintentional bias from the researcher to the participant	Increase staffing as an independent person is needed to undertake the blinding process
Do not use unclassified (i.e., not stating reproductive status) women as participants even if you are not concerned by the potential influence of reproductive hormones on your outcome measure	Increase homogeneity of hormonal profiles	Reduce between participant variability in hormone status Increase validity of the data	Reduce the availability of eligible participants
Standardise, by quantitative means, time of day, prior exercise, caffeine ingestion, dietary intake and nutritional supplementation, alcohol consumption and smoking as these have been shown to affect the concentration of reproductive hormones	Control extraneous variables	Allow the investigation of X on Y, without the influence of Z	Adds more requirements on the participants by asking them to standardise a large number of variables over a set period of time
Use the term “withdrawal bleed” rather than “period” when referring to the bleed experienced by OCP users	Stop OCP users misidentifying themselves as eumenorrheic based on bleeding patterns	Education; informing women and researchers about the differences between hormonal contraceptive users and non-users
Do not use the terms “menstrual cycle” and “periods” synonymously	Dispel the myth that they are the same things and that these terms can be used interchangeably	Education; informing women and researchers about menstrual cycles and how periods are just one aspect of that cycle
Do not impose any menstrual cycle language upon HC users (i.e., trying to match certain days of the OCP cycle with eumenorrheic phase descriptions, e.g., calling the first five days of OCP taking as the early follicular phase of the menstrual cycle)	Prevent confusion between hormonal contraceptive users and non-users	Allows HC users to describe their own status without adding unnecessary complexity or without misperception
Report gestational age based on ultrasound dating rather than on last menstrual period	Increase the accuracy of reporting of gestational age	Reduce the ambiguity in defining participants in studies involving pregnant women
Consider the timescale for resumption of eumenorrheic cycles following childbirth (i.e., in the postpartum period), given that this varies considerably between women	Reduce the assumption that all postpartum women who do not use hormonal contraceptives have eumenorrheic cycles	Reduce ambiguity in defining participants in studies involving postpartum women
Do not use the term post-menopausal based on participants’ age solely	Protect against including irrelevant participants and to increase the homogeneity of hormonal profiles	Reduce between participant variability in hormone status Increase validity of the data	Increase the time and economic burden to correctly identify and confirm post-menopausal status
Do not report gynaecological age (i.e., number of years from menarche to recruitment in the study) as a characteristic of menstrual function (i.e., to illustrate the number of years with eumenorrheic menstrual cycles)	Reduce the assumption that the time between menarche and recruitment is filled with eumenorrheic cycles	Reduce ambiguity in defining participants in studies involving eumenorrheic women
Include an online supplement with additional in-depth information about reproductive status; e.g., data from questionnaires on menstrual cycle status or hormonal contraceptive use, blood marker data, etc	Provide data that can be used for future meta-analyses in studies with women as participants	Quickly increase our understanding of female physiology in relation to sport and exercise science

The considerations in this table have been developed by the authors for this paper

HC Hormonal contraceptives, OCP oral contraceptive pill OCP