Accumulating online discussions suggest some women have experienced menstrual changes after receiving the COVID-19 vaccine. This is important and potentially concerning, as a large proportion of people menstruate and menstrual health is increasingly recognised as an important indicator and determinant of broader health and quality of life. The extent, nature, and mechanism of COVID-19 vaccine-related menstrual changes is currently unclear. The menstrual cycle is regulated by a complex interplay of hormones that can interact with the immune system to influence menstrual bleeding and premenstrual symptoms; vaccines cause huge immune disruptions and so could plausibly affect menstrual features. Questions about menstruation were added to the most recent questionnaire sent to ALSPAC participants. In this project, we will explore 1) the prevalence of different types of vaccine-associated menstrual disruptions, 2) demographic and life history factors associated with experiencing menstrual disruptions, 3) through future ALSPAC planned follow-ups, the duration of menstrual disruptions and future reproductive health outcomes.

Aim(s) and objective(s)
We would like to propose adding a set of questions around menstruation and pandemic-related menstrual changes to the ALSPAC questionnaires. The resulting data would enable us and others to:
1) estimate the prevalence and extent of menstrual changes during the pandemic and describe the demographic of people experiencing these changes;
2) study the potential bidirectional relationship between menstruation and COVID symptoms,
3) study the relationship between menstrual changes and stress and lifestyle changes;
4) study the longer term effects of pandemic-related menstrual changes on later health and reproductive outcomes (for example, fertility, pregnancy outcomes and timing of menopause).
Methods (including an overview of statistical methods)
The questions we are proposing to add were developed for a large online survey of menstrual changes during the pandemic. The questions were developed by Alexandra Alvergne's group at the University of Oxford with input from clinical gynaecologists and PPI input from long-covid sufferers and women with menstrual disorders. The survey is currently live.
Exposures, outcomes and confounders to be considered (justifying particular types of data as necessary)
If/when the data from our proposed questions are collected, we will put in another proposal for a project to address specific research questions.

That research will likely require access to ALSPAC data on stress, lifestyle changes and COVID symptoms from the COVID questionnaires and longitudinal data on menstruation from the G1 and G0 questionnaires. Follow-up ALSPAC questionnaires will allow us to see variations in fertility and timing of menopause according to responses to our questions. Covariates of interest will include socioeconomic position, chronic health conditions, age and BMI.
Reasons for using ALSPAC
ALSPAC has detailed prospectively collected longitudinal data on experiences before and during the COVID pandemic. It is also unique in terms of the availability of data on menstruation prior to the pandemic. Some cohorts have collected data on cycle length, but ALSPAC appears to be the only cohort to have asked about pre-menstrual symptoms like irritability and fatigue.
What do you think the likely impact of your research will be?
Judging by the interest in news stories and blog posts about the small number of survey studies we identified in our systematic review, we estimate that this research will be of wide public interest.
Stigma and a lack of knowledge about what is ‘normal’ means menstrual disorders are often under-reported and under-diagnosed, but they affect a large proportion of the population. For example, in the UK, 5% of women aged 30-49 years (>439,380 women) consult their GP each year due to excessive uterine bleeding. Our systematic review suggests that the number of women suffering from menstrual disorders has likely increased. Therefore, in addition to patients themselves, the research will be of interest to clinicians providing care to menstruating women. Recent years have seen an exponential interest in menstrual health and an appreciation of its role as an indicator and determinant of broader health and wellbeing. This is reflected by very recent policy changes to reduce tax on menstrual products. We anticipate that our research will contribute to further policy changes around improving population menstrual health and quality of life for menstruating women.