Investigating trends in those who experience menstrual bleeding changes after SARS-CoV-2 vaccination

Consensus recommendations for measuring the impact of contraception on the menstrual cycle in contraceptive clinical trials

OBJECTIVE

We sought to develop consensus recommendations for measurement and analysis of data on contraceptive-induced menstrual changes (CIMCs) in contraceptive clinical trials. We built upon previous standardization efforts over the last 50 years and prioritized input from a variety of global experts and current regulatory authority guidance on patient-reported outcomes.

STUDY DESIGN

We completed a formal consensus-building process with an interdisciplinary group of 57 experts from 30 organizations and 14 countries in five global regions who work across academia, nonprofit research organizations, the pharmaceutical industry, and funding agencies. Smaller topical working groups drafted and revised recommendations.

RESULTS

We developed 44 consensus recommendations, including research approaches to establish the evidence for future improvement in the measurement and analysis of CIMC data and guidance for investigators to implement presently. Priority recommendations call for simplification of terminology to make measurement accessible and patient-centered, accounting for intrinsic and extrinsic factors that may impact outcomes during study design and recruitment, standardized data collection of primary CIMC and acceptability outcomes, and harmonized approaches for analysis of these data, including addressing missing data.

CONCLUSION

By virtually convening a large group of global experts working across disciplines and sectors via a formal methodology, we developed consensus recommendations that will improve the current and future measurement and analysis of CIMC data in contraceptive clinical trials. Using these standardized approaches will permit valid and reliable contraceptive product labeling on CIMC outcomes that matter to users and greater comparability across trials that can inform clinical guidance and contraceptive counseling.

IMPLICATIONS

Consensus recommendations on measuring bleeding changes and related outcomes in contraceptive clinical trials can improve reporting of standardized, patient-centered outcomes in future product labeling. These improvements can enable healthcare providers to offer more relevant guidance on contraceptives and users to make more informed decisions about their choice of method.

General practitioner consultation for postmenopausal bleeding after COVID-19 vaccination-a self-controlled cohort study

AIMS

The incidence of postmenopausal bleeding (PMB) has been increasing over the past years. Little is known about the risk of PMB after COVID-19 vaccination. Our study aimed to investigate this based on routine general practitioner (GP) healthcare data from the Netherlands.

METHODS

A retrospective self-controlled cohort study was performed, which included women aged ≥50 years who received at least 1 COVID-19 vaccination in 2021 and were registered in the GP databases of Nivel (the Nivel Primary Care Database, Nivel-PCD) or PHARMO by 1 January 2021. GP consultations for PMB in the exposed period (28 days after each COVID-19 vaccination) were compared with the nonexposed period (all-time outside the exposed period). Incidence rate ratios (IRRs) were calculated using Poisson regression, adjusting for SARS-CoV-2 infection during the study follow-up period.

RESULTS

A total of 692 760 COVID-19 vaccinated women aged ≥50 years were included. No increased GP consultations for PMB was observed for all COVID-19 vaccines together, as well as when stratifying the results by vaccine type (mRNA vs. vector) and vaccine brand (Pfizer/BioNTech, Moderna, AstraZeneca, Johnson & Johnson). After the second Moderna dose an adjusted IRR of 1.47 (95% confidence interval: 0.93-2.32) was observed and after the third Pfizer/BioNTech dose an adjusted IRR of 1.33 (95% confidence interval: 0.92-1.93); however, these results were not statistically significant.

CONCLUSION

No increased number of GP consultations for PMB in primary care was observed after COVID-19 vaccination in general, nor for any of the COVID-19 vaccine brands, vaccine doses or potential risk groups.

Broad-Spectrum Adverse Events of Special Interests Based on Immune Response Following COVID-19 Vaccination: A Large-Scale Population-Based Cohort Study

Background/Objectives: Current studies on adverse events related to the COVID-19 vaccine have predominantly focused on severe, life-threatening side effects. However, numerous less severe but common adverse events (AEs) remain underreported and insufficiently investigated despite their potential impact. Methods: This population-based cohort study investigated the cumulative incidence rate (cIR) and risk of the broad-spectrum AEs of special interests (AESIs) based on immune response, including gynecological, dermatological, ophthalmological, otologic, and dental problems, following COVID-19 vaccination. Results: Among 4,203,887 individuals in Seoul, South Korea, the final analysis included 1,458,557 vaccinated subjects and 289,579 non-vaccinated subjects after the exclusion of underlying diseases. The cIR of AESIs for three months was significantly higher in vaccinated subjects than in non-vaccinated subjects, except for endometriosis. The vaccination significantly increased the risks of all the AESIs except for visual impairment. The risk of alopecia showed the highest HRs (HR [95% CI] = 2.40 [1.90-3.03]) among the AESIs following COVID-19 vaccination. Among the vaccinated subjects, heterologous vaccination was associated with the increased risk of most of the AESIs. Conclusions: Our findings suggest that clinicians should closely recognize and follow up on various COVID-19 vaccine-related AEs due to their unknown impact, even if they may not be serious at present.

Coronavirus disease vaccine linked menstrual changes: mobile application study

OBJECTIVE

Since coronavirus disease 2019 (COVID-19) vaccination began, abnormal uterine bleeding (AUB) has occurred at a high rate. This study assessed the association between COVID-19 vaccination and AUB.

METHODS

In this retrospective cohort study, we analyzed mobile application data on menstrual cycles to investigate differences in the prevalence, duration, and amount of intermenstrual bleeding (IMB) after COVID-19 vaccination. We also analyzed the duration of menstruation, menstrual cycle length, and associated symptoms after the COVID-19 vaccination. Additionally, we investigated the prevalence of IMB according to the vaccine type.

RESULTS

After vaccination, IMB prevalence increased to 3.35% (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.46-1.76; p<0.0001) and IMB duration increased by 0.43 days (95% CI, 0.25-0.60; p<0.0001). The proportion of respondents whose amount of IMB was heavier than regular menstruation increased (OR, 2.96; 95% CI, 1.47-5.93; p=0.002). Menstrual duration decreased by -0.01 days (95% CI, -0.023 to 0.003; p=0.114), and menstrual cycle length increased by 1.39 days (95% CI, 1.30-1.48; p<0.0001). The proportion of participants who answered that there was a difference in menstruation amount increased (OR, 1.52; 95% CI, 1.41-1.64; p<0.0001). The prevalence of IMB increased regardless of the vaccine type.

CONCLUSION

There were statistically significant differences in the prevalence, duration and amount of IMB, menstrual duration, menstrual cycle length, and menstrual amount after COVID-19 vaccination. However, these values were not clinically meaningful and could be regarded as within the normal menstruation range.

Artificial intelligence models predicting abnormal uterine bleeding after COVID-19 vaccination

The rapid deployment of COVID-19 vaccines has necessitated the ongoing surveillance of adverse events, with abnormal uterine bleeding (AUB) emerging as a reported concern in vaccinated females. We aimed to develop a machine learning (ML) model to predict post-vaccination AUB in women aged less than 50 years. A large-scale national cohort, the Korean Nationwide Cohort (K-COV-N cohort), was utilized, comprising over 7 million participants. The study employed advanced ML techniques, including ensemble models combining gradient boosting machine and logistic regression, and conducted feature importance analysis. The dataset was meticulously curated, focusing on relevant demographics and variables, and balanced using Synthetic Minority Over-sampling Technique. Using a national cohort of over 2 million COVID-19 vaccinated cases in South Korea, we developed a ML model for AUB prediction. Our study is the first to develop a predictive model for post-vaccination AUB, employing feature importance analysis to identify the key contributing factors. The analysis revealed three primary predictive features: COVID-19 vaccination frequency, NVX-CoV2373 (Novavax) COVID-19 vaccination count, and hemoglobin levels. These findings provide valuable insights into predicting the risk AUB following COVID-19 vaccination, potentially enhancing post-vaccination monitoring strategies.

Alterations in menstrual characteristics and associated factors in Chinese women post SARS-CoV-2 infection: a cross-sectional study

OBJECTIVE

Following a significant relaxation of restrictions in China on December 7, 2022, after a surge in SARS-CoV-2 infections, an uptick in women presenting with menstrual disorders was observed in clinics. This study aimed to explore the alterations in menstrual characteristics and associated factors post SARS-CoV-2 infection.

METHODS

A cross-sectional online survey was conducted among 869 non-amenorrheic adult Chinese females (aged 18-53) to study the changes in menstrual characteristics and other infection-related factors post initial SARS-CoV-2 infection. The reported menstrual changes (group A) were compared to the reported no menstrual changes (group B). Data collected included basic individual-level information such as age, height, weight, menstrual history, reproductive and menstrual disorders, chronic diseases, SARS-CoV-2 vaccination status, COVID-19 symptoms, and changes in menstrual characteristics (regularity, period volume, and degree of dysmenorrhea) post SARS-CoV-2 infection.

RESULTS

Of the 869 participants, 442 (50.9%, group A) reported alterations in at least one menstrual characteristic; 171 (19.7%) experienced an extended menstrual cycle, and 122 (14.0%) reported a decrease in menstrual volume. Participants who reported menstrual changes (group A) were more likely to have pre-existing chronic diseases (7.7% vs. 3.0%, P = 0.003) and exhibit more symptoms of COVID-19 during the acute (4.94 vs. 4.03, P < 0.001) and recovery (4.37 vs. 3.41, P < 0.001) phases. These participants were also more likely to report fever as a COVID-19 symptom (93.4% vs. 86.9%, P = 0.001) and experienced a longer duration of fever (2.25 vs. 1.96 days, P = 0.001) as compared to group B. Notably, group A with chronic diseases, fewer vaccine doses, and more COVID-19-related symptoms experienced more frequent menstrual changes post COVID-19 (P < 0.05) than group B.

CONCLUSION

Participants with chronic diseases, fewer vaccination doses, and more COVID-19-related symptoms may experience more frequent menstrual changes post COVID-19 infection according to the self-report results in this study.

Factors associated with menstrual-related disturbances following SARS-CoV-2 vaccination: a Spanish retrospective observational study in formerly menstruating women

BACKGROUND

A growing body of evidence suggests a potential link between the SARS-CoV-2 vaccine and menstrual changes in women who were menstruating at the time of vaccination. Nevertheless, the prevalence of this event in those with secondary amenorrhea for different causes, i.e. formerly menstruating women, remains unclear. It is plausible that, analogous to those observed in currently menstruating women, they experienced some degree of alteration in their reproductive health, defined here as menstrual-related disturbances.

OBJECTIVE

The aim was to analyze this phenomenon and identify the factors associated with the occurrence of menstrual-related disturbances in this subpopulation. Study design: A retrospective observational cross-sectional study was conducted among adult Spanish in December 2021 using an online survey (N = 17,512). The present analysis includes a subpopulation of vaccinated and formerly menstruating women (N = 548). General characteristics, medical history, and adverse events following COVID-19 vaccination were recorded. Chi-square, Mann-Whitney U and McNemar mid-P tests were performed. Bivariate logistic regression was then used to identify the key factors influencing this unexpected event.

RESULTS

In comparison with the first dose, significantly higher percentages of respondents experienced menstrual-related disturbances (dose 1: 38.5 percent vs. dose 2: 44.8 percent) after receiving the second one. Among them, those related to the length and flow stand out, being of long-term nature in about 17-20 percent of cases. Interindividual factors influencing this unexpected event after receiving the dose 1 may include weight, perimenopause, preexisting diagnoses of non-autoimmune rheumatic/articular conditions, use of hormonal contraceptives, suffering from other vaccine side effects - such as arm pain and the number of previous pregnancies; for dose 2, these factors may include suffering from menstrual-related alterations after receiving dose 1, as well as the use of hormonal contraceptives and perimenopause.

CONCLUSION

Formerly menstruating women might experience long-term menstrual-related disturbances following COVID-19 vaccination. Potential influencing factors include weight, perimenopause, rheumatic/articular conditions, hormonal contraceptives, vaccine side effects and previous pregnancies.

Association between the COVID-19 vaccination campaign and fertility trends: a population-level time series analysis for 22 countries

Introduction

At the turn of 2021-2022, monthly birth rates declined in many higher-income countries. We explore how the rollout of COVID-19 vaccination was associated with this decline.

Methods

Using an interrupted time series design, we evaluate the impact of the onset of the COVID-19 pandemic and the start of COVID-19 vaccination on seasonally adjusted monthly total fertility rates in 22 high-income countries. We study the associations between COVID-19 vaccination and fertility by additionally controlling for youth unemployment, stringency index and vaccination coverage. Fertility data come from the Short-Term Fertility Fluctuations data series under the Human Fertility Database. Indicators used as control variables originate from Eurostat and OECD databases, Oxford COVID-19 Government Response Tracker and Our World in Data.

Results

The start of the pandemic had an immediate effect on fertility in most countries, although the size and direction of level changes considerably varied across them. The impact of COVID-19 vaccination was likewise extensive. While a relatively pronounced negative association between the COVID-19 vaccine rollout and fertility 9 months later was found only for 10 out of 22 countries, indications of a negative fertility response were detected in the vast majority of countries. For several countries, the decline was preceded by fertility increase that took place after the onset of the pandemic. Only 4 out of 22 countries had post-vaccination fertility declines that resulted in fertility being on lower level than what the pre-pandemic trend predicted. Additional control variables changed the associations only a little.

Conclusions

The COVID-19 vaccination campaign contributed to the variation in short-term fertility trends. Several countries experienced declines following the campaign, which often returned fertility closer to the pre-pandemic trend. Fertility appears to have responded in short run to vaccination, but only in few cases such that the long-term trajectory is below the pre-pandemic trend.

Relation Between COVID-19 Infection and Vaccine and Menstrual Cycle Changes of Portuguese Adolescents in Higher Education

In a period globally known as long COVID, several post-acute infection sequelae and vaccination effects have been discussed.

OBJECTIVES

This study aimed to identify the effects of COVID-19 infection and vaccines on the menstrual cycle of adolescents attending higher education and to verify the association between personal health factors and changes in their menstrual cycle after contact with the virus SARS-CoV-2 via infection or via the vaccine.

METHODS

A cross-sectional study was conducted using a questionnaire for data collection, applied online to Portuguese higher education adolescents aged between 18 and 24. The sample included 401 individuals. The statistical analysis of data was performed using SPSS.

RESULTS

More than half of the sample had a COVID-19 infection only once and took two doses of the vaccine. The mRNA Comirnaty 30 µg BioNTech vaccine was administered to 73.1%. The most common menstrual changes were an increase in blood clots, the blood becoming darker, shorter menstrual cycles, scarcer blood flow, and more irregular cycles. Menstrual changes correlated significantly with vaccination but not with infection.

CONCLUSIONS

This study showed a lower percentage of women affected than other studies carried out closer to the pandemic period, which could mean that the effects are diminishing over time. Thus, adolescents' menstrual health should be monitored.

The biological and psychological impact of the Coronavirus disease-19 pandemic on the characteristics of the menstrual cycle

The Coronavirus disease-19 (COVID-19) pandemic was declared in March 2020 by the World Health Organization. The severe acute respiratory syndrome-coronavirus-2 virus enters host cells through angiotensin-converting enzyme 2 receptors and transmembrane serine protease type II that are expressed in pulmonary alveoli, as well as in hepatocytes, endothelium, ovaries, uterus, vagina, thyroid, and other tissues. In addition to viral injury, the COVID-19 pandemic, through protective measures such as social isolation and lockdown, has promoted a scenario of psychosocial stress, especially in women. In this context of isolation, anxiety, fear, and mental distress, there is dysregulation of the hypothalamic-pituitary-adrenal axis and subsequent gonadal side effects. Furthermore, studies report an association between COVID-19 and temporary menstrual cycle alterations such, as increased cycle duration, decreased cycle duration, increased menstrual flow, dysmenorrhea, and amenorrhea. Regarding COVID-19 vaccination, menstrual irregularities have been observed in about half of the women, predominantly with a decrease in cycle duration and increased menstrual flow, but without fertility sequelae. The aim of this study was to review the most up-to-date information on the relationship between the COVID-19 pandemic and menstrual irregularities.

Covid-19 vaccination and menstrual bleeding disturbances among women of fertile age: a Norwegian registry study

This study evaluated the relationship between Covid-19 vaccination and menstrual bleeding disturbances using a large national registry linkage including 666,467 women between 20 and 40 years of age residing in Norway on January 1st, 2019. Information on vaccination-BNT162b2 and mRNA-1273 - was obtained from the Norwegian vaccination registry. Diagnoses of menstrual disturbances (absent/scanty, excessive, irregular/frequent menstruation, and intermenstrual bleeding) was obtained from the general practitioner database. We examined new-onset menstrual bleeding disturbances using a Cox regression comparing vaccinated to unvaccinated women, where women contributed follow-up time as unvaccinated until the day of vaccination. In addition, we conducted a self-controlled case-series analysis, and a sensitivity analysis excluding all those who remained unvaccinated throughout the pandemic, to evaluate the role of unmeasured confounding. We observed an increased risk of several menstrual bleeding disturbances after vaccination against Covid-19, ranging from an adjusted HR (aHR) of 1.18 (95% CI: 1.04, 1.33) for intermenstrual bleeding to 1.29 (95% CI: 1.23, 1.36) for irregular/frequent menstrual periods. However, estimates were fully attenuated when excluding women who remained unvaccinated at the end of follow-up (aHRs between 0.97 and 1.08). No differences were identified according to vaccine dose or type. Our self-controlled case series analysis confirmed no increased risk after a first dose of vaccination, though there was a slightly increased risk of menstrual bleeding disturbances from 61 days after vaccination with dose 2. In conclusion, the modestly increased risk of menstrual bleeding disturbances after Covid-19 vaccination appeared to reflect a role of unmeasured confounding by women who never received Covid-19 vaccinations, as associations did not remain when risk after vaccination were compared to risk before vaccination among ever vaccinated women.

COVID-19 vaccination and postmenopausal bleeding: a retrospective cohort study

OBJECTIVE

COVID-19 vaccination has been related to menstrual irregularities; however, the effect on postmenopausal women is unknown. The aim of this study was to analyze the prevalence of postmenopausal bleeding (PMB) after COVID-19 vaccination.

METHODS

A retrospective study was conducted in the Department of Gynecology in Hospital del Mar. Consecutive postmenopausal women with data available and endometrial biopsy were included between February 2021 and January 2022. Patients were stratified between COVID-19 vaccinated and unvaccinated groups. PMB after 30 days from last vaccine dose was considered unrelated to vaccine. Endometrial pathology diagnoses were stratified into benign or malignant. Univariable and multivariable of regression analysis on variables potentially associated with PMB was performed.

RESULTS

A total of 381 patients were included, 91 in the vaccinated group and 290 in the unvaccinated group. Prevalence of PMB in the vaccinated group was 75.8% compared to 59.0% in the unvaccinated group (p < 0.005). No increase in endometrial malignant pathology was observed among the vaccinated group (p = 0.189). Multivariable analysis that correlates factors associated with PMB suggests COVID-19 vaccine and malignant endometrial biopsy as independent risk variables.

CONCLUSIONS

A higher prevalence of PMB was associated with COVID-19 vaccine. Endometrial histological results showed no association with COVID-19 vaccination, but endometrial biopsy should be performed for PMB.

Effect of Coronavirus Disease 2019 Pandemic and Vaccination on Menstrual Cycle Among King Saud University Students in Riyadh: A Retrospective Online Survey

Objectives We aimed to evaluate the prevalence of menstrual cycle changes following the COVID-19 pandemic and the COVID-19 vaccination among female students at King Saud University in Riyadh, Saudi Arabia. Methods A cross-sectional retrospective study using an online questionnaire was conducted between October 2022 and December 2022. Data were collected concerning demographic variables, clinical conditions, menstrual cycle characteristics, COVID-19 infection status, and vaccination history. Results Of the 525 female students who participated in the study (mean age, 21.5 ± 3.9 years; mean body mass index, 22.7 ± 4.7 kg/m2), 246 (46.9%) had tested positive for COVID-19, 15 (2.9%) had visited the emergency room, and eight (1.5%) had been hospitalized. The average duration between menstrual cycles increased significantly among the study sample (pre-pandemic, 25.9 ± 5.3 days; post-pandemic, 26.8 ± 6.7 days; p = 0.016). Pre-pandemic, 221 (42.1%) participants reported less than two days of variance between their shortest and longest cycles, as compared with 175 (33.3%) post-pandemic (p < 0.001). Regarding vaccination, 393 (74.9%) participants had received three vaccinations, and 110 (21%) had received two vaccinations. Post-vaccination, 184 (35%) participants reported no changes to their menstrual cycle, 154 (29.3%) reported less disruption, and 44 (8.4%) experienced more disrupted menstrual cycles. Conclusion This study highlights potential associations between the COVID-19 pandemic, subsequent vaccinations, and changes in menstrual patterns, which can help to elucidate the physiological and psychological effects of pandemics and vaccination campaigns on women's health. Future studies must consider biological and psychosocial factors to elucidate underlying mechanisms and causal relationships.

The prevalence of menstrual changes in COVID-19 vaccinated women: A cross-sectional study

Background

This study aimed to examine the prevalence of menstrual cycle changes (MCs) and their patterns among healthy Syrian women following the administration of the first and second doses of a vaccine.

Methods

A cross-sectional online survey following campaigns for COVID-19 vaccines was conducted in 2022 from June 26 to August 3. Data collected included the participants' demographic characteristics, vaccination status, and multiple-choice questions for MCs changes after the first and second doses.

Results

Of 236, 89.8 % completed all shots of the vaccine. After the first dose, 36.9 % reported MCs, and 35 % after the second dose. Most women did not experience changes in menstrual cycle frequency-81.8 % after the first dose and 83.4 % after the second dose. Similarly, most women did not observe changes in cycle length, or menstrual flow quantity-5.5 % after the first dose and 8 % after the second dose reported spotting. Dysmenorrhea was reported by 15.7 % and 14.1 % of women after the first and second doses, respectively.

Conclusion

MCs are a potential symptom that a healthy woman at childbearing age could have after a different type of COVID-19 vaccine. MCs patterns do not significantly differ following vaccine doses.

Physiological Response to the COVID-19 Vaccine: Insights From a Prospective, Randomized, Single-Blinded, Crossover Trial

BACKGROUND

Rapid development and implementation of vaccines constituted a crucial step in containing the COVID-19 pandemic. A comprehensive understanding of physiological responses to these vaccines is important to build trust in medicine.

OBJECTIVE

This study aims to investigate temporal dynamics before and after COVID-19 vaccination in 4 physiological parameters as well as the duration of menstrual cycle phases.

METHODS

In a prospective trial, 17,825 adults in the Netherlands wore a medical device on their wrist for up to 9 months. The device recorded their physiological signals and synchronized with a complementary smartphone app. By means of multilevel quadratic regression, we examined changes in wearable-recorded breathing rate, wrist skin temperature, heart rate, heart rate variability, and objectively assessed the duration of menstrual cycle phases in menstruating participants to assess the effects of COVID-19 vaccination.

RESULTS

The recorded physiological signals demonstrated short-term increases in breathing rate and heart rate after COVID-19 vaccination followed by a prompt rebound to baseline levels likely reflecting biological mechanisms accompanying the immune response to vaccination. No sex differences were evident in the measured physiological responses. In menstruating participants, we found a 0.8% decrease in the duration of the menstrual phase following vaccination.

CONCLUSIONS

The observed short-term changes suggest that COVID-19 vaccines are not associated with long-term biophysical issues. Taken together, our work provides valuable insights into continuous fluctuations of physiological responses to vaccination and highlights the importance of digital solutions in health care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s13063-021-05241-5.

COVID-19 and menstrual-related disturbances: a Spanish retrospective observational study in formerly menstruating women

Introduction

Four years after the start of the pandemic, there is limited evidence on the impact of COVID-19 on the women's health regardless of their reproductive status.

Objective

The aim was to analyze the prevalence and associated factors of menstrual-related disturbances in formerly menstruating women following SARS-CoV-2 infection.

Study design

A retrospective observational study of adult women in Spain was conducted during the month of December 2021 using an online survey (N = 17,512). The present analysis includes a subpopulation of SARS-CoV-2-infected and formerly menstruating women (n = 72). The collected data included general characteristics, medical history, and specific information on COVID-19. Chi-square and Mann-Whitney U-tests were performed. Bivariate logistic regression analysis was then performed to investigate possible associations between the occurrence of menstrual-related disturbances after SARS-CoV-2 infection.

Results

38.8% of participants experienced menstrual-related disturbances following COVID-19. Among these, unexpected vaginal bleeding (20.8%) was the most common event, followed by spotting (11.1%) ( Table 1). Other reported changes were in the length (shorter = 12.5%) and flow (heavier = 30.3%) of menstrual bleeding in comparison to their previous experience. Regression analysis revealed that being a perimenopausal woman [adjusted odds ratio (AOR) 4.721, CI 95%, 1.022-21.796, p = 0.047] and having a previous diagnosis of menorrhagia (AOR 5.824 CI 95%, 1.521-22.310, p = 0.010) were factors associated with the event.

Conclusion

These findings could help health professionals provide their patients with up-to-date scientific information to empower them to actively manage their reproductive health, especially in societies where menstrual health is still taboo.

Measurement of changes to the menstrual cycle: A transdisciplinary systematic review evaluating measure quality and utility for clinical trials

Despite the importance of menstruation and the menstrual cycle to health, human rights, and sociocultural and economic wellbeing, the study of menstrual health suffers from a lack of funding, and research remains fractured across many disciplines. We sought to systematically review validated approaches to measure four aspects of changes to the menstrual cycle-bleeding, blood, pain, and perceptions-caused by any source and used within any field. We then evaluated the measure quality and utility for clinical trials of the identified instruments. We searched MEDLINE, Embase, and four instrument databases and included peer-reviewed articles published between 2006 and 2023 that reported on the development or validation of instruments assessing menstrual changes using quantitative or mixed-methods methodology. From a total of 8,490 articles, 8,316 were excluded, yielding 174 articles reporting on 94 instruments. Almost half of articles were from the United States or United Kingdom and over half of instruments were only in English, Spanish, French, or Portuguese. Most instruments measured bleeding parameters, uterine pain, or perceptions, but few assessed characteristics of blood. Nearly 60% of instruments were developed for populations with menstrual or gynecologic disorders or symptoms. Most instruments had fair or good measure quality or clinical trial utility; however, most instruments lacked evidence on responsiveness, question sensitivity and/or transferability, and only three instruments had good scores of both quality and utility. Although we took a novel, transdisciplinary approach, our systematic review found important gaps in the literature and instrument landscape, pointing towards a need to examine the menstrual cycle in a more comprehensive, inclusive, and standardized way. Our findings can inform the development of new or modified instruments, which-if used across the many fields that study menstrual health and within clinical trials-can contribute to a more systemic and holistic understanding of menstruation and the menstrual cycle.

Association between COVID-19 vaccination and menstruation: a state of the science review

INTRODUCTION

Menstrual health is a key patient-reported outcome beyond its importance as a general indicator of health and fertility. However, menstrual function was not measured in the clinical trials of COVID-19 vaccines. The purpose of this review was to synthesise the existing literature on the relationship between COVID-19 vaccination and menstrual health outcomes.

METHODS

A PubMed search to 31 October 2023 identified a total of 53 publications: 11 prospective cohort studies, 11 retrospective cohort studies or registry-based cohort studies, and 31 cross-sectional or retrospective case-control studies.

RESULTS

Identified studies were generally at moderate-to-high risk of bias due to retrospective design, interviewer bias, and failure to include a non-vaccinated control group. Nonetheless, the bulk of the literature demonstrates that COVID-19 vaccine is associated with temporary changes in menstrual characteristics (cycle length and flow) and menstrual pain. Follicular phase (at the time of vaccination) is associated with greater increases in cycle length. Evidence suggests temporary post-vaccine menstrual changes in adolescents, abnormal vaginal bleeding in postmenopausal individuals, and a potential protective effect of using hormonal contraception.

CONCLUSIONS

In this review we found evidence supporting an association between the COVID-19 vaccine and menstrual health outcomes. Given the importance of menstrual function to overall health, we recommend that all future vaccine trials include menstruation as a study outcome. Future vaccine studies should include rigorous assessment of the menstrual cycle as an outcome variable to limit sources of bias, identify biological mechanisms, and elucidate the impact of stress.

The direct effect of SARS-CoV-2 virus vaccination on human ovarian granulosa cells explains menstrual irregularities

Following administration of the SARS-CoV-2 vaccine, many women worldwide reported short-term menstrual irregularities. Although menstrual bleeding, "the fifth vital sign", is experienced by more than 300 million people on any given day worldwide, these changes were only partially studied. Irregular periods are important well beyond fertility and the discomfort they impose; they are associated with the risk of cardiovascular morbidity, chronic diseases, and premature mortality. Pre-clinical examination of the vaccine polymeric envelope indicates its accumulation in the ovaries. The somatic endocrine cells of the ovarian follicle - the granulosa cells (GCs)-participate in the strict hypothalamic-pituitary-ovarian (HPO) feedback loop that governs the menstrual cycle via endocrine and paracrine regulators, as AMH and Inhibins. We aimed to unravel the direct effect of the COVID-19 vaccine on GCs and link their post-vaccine activity to changes in menstrual patterns. Human primary GCs exposed in-vitro to the Pfizer COVID-19 vaccine BNT162b2, demonstrated no change in their viability but altered mRNA transcripts, specifically of the regulatory key factors: InhibinB was upregulated, whereas AMH was downregulated. We further examined pre- and post-vaccination blood samples from individual women and found a 2-3 folds change in the post-vaccination FSH/InhibinB protein level ratio, compared to their pre-vaccination values. This altered expression of InhibinB could significantly impact the HPO axis in vaccinated women and may ultimately influence the endometrium cyclicity, manifested clinically by the commonly reported changes in menstrual bleeding patterns.

Menstrual Cycle Disturbances after COVID-19 Vaccination: A Cross-Sectional Study

BACKGROUND

Following COVID-19 vaccination, some women suffered from menstrual cycle disturbances. This study aimed to investigate menstrual cycle disturbances after COVID-19 vaccination in women of reproductive age.

MATERIALS AND METHODS

This cross-sectional study was performed on 407 vaccinated women in the vaccination center of Imam Hossein Hospital (Tehran, Iran) between October 2021 and October 2022. They were interviewed based on a research-made checklist which consisted of two areas of questions about the baseline characteristics of participants and menstrual cycle characteristics to explore menstrual characteristics following COVID-19 vaccination.

RESULTS

The prevalence of menstrual disturbances was higher after the third dose (38.3%) compared with the second (27.9%) and first (17.7%) doses (P<0.001). After the first dose, a history of polycystic ovarian syndrome [PCOS, odds ratio (OR)=7.35, 95% confidential interval (CI)= (3.64-14.82), P<0.001] and menstrual disturbances with unknown etiology [OR=15.23, 95% CI=(6.30-36.80), P<0.001] could predict menstrual disturbances. After the second dose, a history of menstrual disturbances with unknown etiology [OR=3.83, 95% CI=(1.47-9.94), P=0.006] and menstrual disturbances after the first dose [OR=201.96, 95% CI= (40.99-994.90), P<0.001] were predictors of menstrual disturbances. After the third dose, a history of menstrual disturbances with unknown etiology [OR=3.09, 95% CI= (1.00-9.52), P=0.048], menstrual disturbances after the first [OR=9.82, 95% CI=(1.38-69.69), P=0.022] and second [OR=7.83, 95% CI=(1.46-41.92), P=0.016] doses could predict menstrual disturbances.

CONCLUSION

We detected that many women experienced various menstrual disturbances after vaccination against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Furthermore, a history of menstrual abnormalities (before COVID-19 vaccination and following the previous doses of these vaccines) was associated with developing menstrual disturbances.

COVID-19 (SARS-CoV-2) mRNA vaccination does not affect basal sex hormone levels (follicle-stimulating hormone, luteinizing hormone, estradiol) in reproductive-age women

OBJECTIVE

People vaccinated with the coronavirus disease 2019 (COVID-19) (severe acute respiratory syndrome coronavirus-2 [SARS-CoV-2]) mRNA vaccine have reported experiencing various adverse effects. For instance, reproductive-age women have presented with complaints of abnormal uterine bleeding or menstrual cycle changes. We speculated that differences in basal sex hormone levels before and after vaccination may be present in women who experienced irregular bleeding or menstrual cycle changes; thus, this study aimed to investigate the differences in basal sex hormone levels of women before and after two doses of SARS-CoV-2 mRNA vaccination.

METHODS

This retrospective study included patients who received SARS-CoV-2 mRNA vaccines between January 2021 and February 2022 at a single center. In an outpatient setting, patients were queried regarding their menstrual cycle, the date of SARS-CoV-2 mRNA vaccination, vaccination type, and vaccination side effects. Differences in basal hormone levels (menstrual cycle days 2-3, follicle-stimulating hormone [FSH], luteinizing hormone [LH], and estradiol) before and after vaccination were compared.

RESULTS

Among the 326 patients, patients with no laboratory records of the hormones were excluded. The median time interval between SARS-CoV-2 mRNA vaccination and the laboratory test day was 79 days (interquartile range, 44 to 127). A comparative analysis of these hormones before and after vaccination revealed no significant differences. Subgroup analyses based on age and reported adverse events also found no statistically significant differences.

CONCLUSION

This study showed no significant differences in basal hormone levels (FSH, LH, and estradiol) before and after SARS-CoV-2 mRNA vaccination.

Association of heavy menstrual bleeding with cardiovascular disease in US female hospitalizations

BACKGROUND

Heavy menstrual bleeding (HMB) is a common menstrual disorder associated with multiple risk factors of cardiovascular disease (CVD) in women. In addition, HMB is often present with irregular menstruation (IM) which is a risk factor for CVD outcomes. However, the relationship between HMB and CVD outcomes is unexplored in the presence or absence of IM. We determined the association of HMB with multiple CVD outcomes using a nationally representative sample of female hospitalizations in the US.

METHODS

All hospitalizations of females with HMB diagnosis and normal menstrual cycles from ages of 18 to 70 years were extracted from the National Inpatient Sample Database, 2017. The HMB was defined using the International Classification of Diseases (ICD)-10 for excessive and frequent menstruation bleeding and included any current or history of HMB diagnosis. Outcomes including major adverse cardiovascular events (MACE), coronary heart disease (CHD), stroke, heart failure (HF), atrial fibrillation (AF) or arrhythmia, myocardial infarction (MI), and diabetes (DM) were defined using ICD-10 codes. Adjusted logistic regression and prosperity scores-matched logistic regression analyses were conducted to summarize adjusted associations with an odds ratio (OR) and a 95% confidence interval (CI).

RESULTS

Among 2,430,851 hospitalizations, HMB was observed in 7762 (0.68%) females with age ≤ 40 years and 11,164 (0.86%) females with age > 40 years. Among hospitalizations with age ≤ 40 years, HMB was significantly associated with increased odds of CVD outcomes including MACE (OR = 1.61; 95% CI: 1.25, 2.08), CHD (OR = 1.72; 95% CI: 1.10, 2.71), stroke (OR = 1.95; 95% CI: 1.12, 3.40), HF (OR = 1.53; 95% CI: 1.15, 2.03), and AF/arrhythmia (OR = 1.84; 95% CI: 1.34, 2.54). These associations were confirmed in multiple sensitivity analyses. In contrast, HMB was not robustly associated with CVD events among hospitalizations of women with age > 40 years. HMB without IM was strongly associated with DM, HF, AF, and MACE outcomes while HMB with IM was strongly associated with CHD and AF outcomes in hospitalizations of young women.

CONCLUSIONS

HMB is associated with CVD events among US hospitalizations of young women. A routine investigation and screening of menstrual disorders, especially HMB, is useful for CVD risk stratification and management in young women.

Abnormal uterine bleeding diagnoses and care following COVID-19 vaccination

BACKGROUND

There is evidence suggesting that COVID-19 vaccination may be associated with small, transitory effects on uterine bleeding, possibly including menstrual timing, flow, and duration, in some individuals. However, changes in health care seeking, diagnosis, and workup for abnormal uterine bleeding in the COVID-19 vaccine era are less clear.

OBJECTIVE

This study aimed to assess the impact of COVID-19 vaccination on incident abnormal uterine bleeding diagnosis and diagnostic evaluation in a large integrated health system.

STUDY DESIGN

Using segmented regression, we assessed whether the availability of COVID-19 vaccines was associated with changes in monthly, population-based rates of incident abnormal uterine bleeding diagnoses relative to the prepandemic period in health system members aged 16 to 44 years who were not menopausal. We also compared clinical and demographic characteristics of patients diagnosed with incident abnormal uterine bleeding between December 2020 and October 13, 2021 by vaccination status (never vaccinated, vaccinated in the 60 days before diagnosis, vaccinated >60 days before diagnosis). Furthermore, we conducted detailed chart review of patients diagnosed with abnormal uterine bleeding within 1 to 60 days of COVID-19 vaccination in the same time period.

RESULTS

In monthly populations ranging from 79,000 to 85,000 female health system members, incidence of abnormal uterine bleeding diagnosis per 100,000 person-days ranged from 8.97 to 19.19. There was no significant change in the level or trend in the incidence of abnormal uterine bleeding diagnoses between the prepandemic (January 2019-January 2020) and post-COVID-19 vaccine (December 2020-December 2021) periods. A comparison of clinical characteristics of 2717 abnormal uterine bleeding cases by vaccination status suggested that abnormal bleeding among recently vaccinated patients was similar or less severe than abnormal bleeding among patients who had never been vaccinated or those vaccinated >60 days before. There were also significant differences in age and race of patients with incident abnormal uterine bleeding diagnoses by vaccination status (Ps<.02). Never-vaccinated patients were the youngest and those vaccinated >60 days before were the oldest. The proportion of patients who were Black/African American was highest among never-vaccinated patients, and the proportion of Asian patients was higher among vaccinated patients. Chart review of 114 confirmed postvaccination abnormal uterine bleeding cases diagnosed from December 2020 through October 13, 2021 found that the most common symptoms reported were changes in timing, duration, and volume of bleeding. Approximately one-third of cases received no diagnostic workup; 57% had no etiology for the bleeding documented in the electronic health record. In 12% of cases, the patient mentioned or asked about a possible link between their bleeding and their recent COVID-19 vaccine.

CONCLUSION

The availability of COVID-19 vaccination was not associated with a change in incidence of medically attended abnormal uterine bleeding in our population of over 79,000 female patients of reproductive age. In addition, among 2717 patients with abnormal uterine bleeding diagnoses in the period following COVID-19 vaccine availability, receipt of the vaccine was not associated with greater bleeding severity.

Impact of COVID-19 infections and vaccination on menstrual cycle symptoms in the south of Jordan: a cross-sectional study

BACKGROUND

Several recent studies have highlighted the need for more evaluation of the impact of COVID-19 infections and vaccines on the reproductive system and menstruation. This study aimed to assess the impact of COVID-19 infection and vaccines on menstrual symptoms.

METHODS

A cross-sectional survey utilizing face-to-face interviews from January 1 to 31 March 2022 was conducted in the city of Al-Karak in southern Jordan. The questionnaire included sociodemographic characteristics, medical and reproductive history, the contraceptive method used if any, menstrual cycle (MC) status, previous medical and drug history, and the impact of infection and vaccination on the MC.

RESULTS

The study questionnaire was completed by 400 participants with a mean age of 32.1±12.6 years. Regarding the history of COVID-19 infections, 33.8% of the participants reported a history of confirmed COVID-19 infections, 77.8% of them did not report any menstrual changes following the infection, while the remaining 22.2% reported changes in menstruation. The most commonly reported post-COVID-19 manifestations were irregular (27.6%) and light menstrual cycle (MC) (24.15) or dysmenorrhea (24.1%). Heavy menstruation was reported by 17.2% of participants post-COVID-19 infection. Two-thirds of the study participants (66.6%) reported no changes in the MC following the administration of the COVID-19 vaccine. The most reported symptoms for those who experienced changes in the MC following the vaccination were irregular cycle (13.1%), heavy menstruation (7%), and light menstruation (7%). Other reported symptoms were dysmenorrhea (4.6%), intermenstrual bleeding (1.2%), and amenorrhea (0.5%).

CONCLUSION

This study revealed minor changes in the MC following COVID-19 infections and administration of the COVID-19 vaccine. These findings are consistent with published reports. It is recommended that future clinical trials for new vaccines for women of childbearing age include outcomes related to sex hormones and MC. Women should be encouraged to take the vaccines and report symptoms to healthcare professionals for further assessment.

Handicraft art leisure activities and cognitive reserve

ObjectiveOlder individuals face a higher likelihood of developing dementia. The rate of cognitive decline resulting from dementia is not equivalent for all, as some patients with dementia are able to function independently longer than others, despite having similar disease burden. The cognitive reserve (CR) theory provides one explanation for the differing rate of decline. CR suggests that there are factors-most notably, educational attainment and occupational attainment-that can protect against the cognitive decline. Although the beneficial effects of these notable CR factors are clear, not all are easily modifiable. Participation in leisure activities may represent a more easily modifiable factor. Some research hints at beneficial effects of leisure activities, although specific leisure activities have not been well examined. The present study examined the relations between handicraft art leisure activities (HALAs) and multiple cognitive domains. MethodArchival WAIS-IV and demographic data for 50 California retirement community residents were examined. ResultsHALA participation accounted for statistically significant variance in working memory performance (R2 = .40, β = .24%) over and above the established CR factors of age, depression, educational attainment, and occupational attainment. In addition, HALA participation was related to a better ability to perform abstract visual information tasks (Block Design subtest, r = .28, p = .05) and non-verbal reasoning tasks (Visual Puzzles subtest, r = .38, p = .008). ConclusionsHALA participation among older adults could contribute to the retention of cognitive function, supporting the role of HALA participation as a CR factor.

Timing of Coronavirus Disease 2019 (COVID-19) Vaccination and Effects on Menstrual Cycle Changes

OBJECTIVE

To assess whether menstrual cycle timing (follicular or luteal phase) of coronavirus disease 2019 (COVID-19) vaccine administration is associated with cycle length changes.

METHODS

We used prospectively collected (2021-2022) menstrual cycle tracking data from 19,497 reproductive-aged users of the application "Natural Cycles." We identified whether vaccine was delivered in the follicular or luteal phase and also included an unvaccinated control group. Our primary outcome was the adjusted within-individual change in cycle length (in days) from the average of the three menstrual cycles before the first vaccination cycle (individuals in the unvaccinated control group were assigned a notional vaccine date). We also assessed cycle length changes in the second vaccination cycle and whether a clinically significant change in cycle length (8 days or more) occurred in either cycle.

RESULTS

Most individuals were younger than age 35 years (80.1%) and from North America (28.6%), continental Europe (33.5%), or the United Kingdom (31.7%). In the vaccinated group, the majority received an mRNA vaccine (63.8% of the full sample). Individuals vaccinated in the follicular phase experienced an average 1-day longer adjusted cycle length with a first or second dose of COVID-19 vaccine compared with their prevaccination average (first dose: 1.00 day [98.75% CI, 0.88-1.13], second dose: 1.11 days [98.75% CI, 0.93-1.29]); those vaccinated in the luteal phase and those in the unvaccinated control group experienced no change in cycle length (respectively, first dose: -0.09 days [98.75% CI, -0.26 to 0.07], second dose: 0.06 days [98.75% CI, -0.16 to 0.29], unvaccinated notional first dose: 0.08 days [98.75% CI, -0.10 to 0.27], second dose: 0.17 days [98.75% CI, -0.04 to 0.38]). Those vaccinated during the follicular phase were also more likely to experience a clinically significant change in cycle length (8 days or more; first dose: 6.8%) than those vaccinated in the luteal phase or unvaccinated (3.3% and 5.0%, respectively; P <.001).

CONCLUSION

COVID-19 vaccine-related cycle length increases are associated with receipt of vaccination in the first half of the menstrual cycle (follicular phase).

COVID-19 and abnormal uterine bleeding: potential associations and mechanisms

The impact of COVID-19 on menstruation has received a high level of public and media interest. Despite this, uncertainty exists about the advice that women and people who menstruate should receive in relation to the expected impact of SARS-CoV-2 infection, long COVID or COVID-19 vaccination on menstruation. Furthermore, the mechanisms leading to these reported menstrual changes are poorly understood. This review evaluates the published literature on COVID-19 and its impact on menstrual bleeding, discussing the strengths and limitations of these studies. We present evidence consistent with SARS-CoV-2 infection and long COVID having an association with changes in menstrual bleeding parameters and that the impact of COVID vaccination on menstruation appears less significant. An overview of menstrual physiology and known causes of abnormal uterine bleeding (AUB) is provided before discussing potential mechanisms which may underpin the menstrual disturbance reported with COVID-19, highlighting areas for future scientific study. Finally, consideration is given to the effect that menstruation may have on COVID-19, including the impact of the ovarian sex hormones on acute COVID-19 severity and susceptibility and reported variation in long COVID symptoms across the menstrual cycle. Understanding the current evidence and addressing gaps in our knowledge in this area are essential to inform public health policy, direct the treatment of menstrual disturbance and facilitate development of new therapies, which may reduce the severity of COVID-19 and improve quality of life for those experiencing long COVID.

Association between COVID-19 and vaccination on menstrual cycle

OBJECTIVE

To evaluate changes in the menstrual pattern of women of reproductive age infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or vaccinated against coronavirus disease 2019 (COVID-19).

METHODS

A cross-sectional study at the University of Campinas, Brazil using Google questionnaire applied from December 2021 through February 2022, disseminated through snowball technique. Participants responded about characteristics of their menstrual cycle before the pandemic and before COVID-19 vaccination, and then about characteristics of their cycle 3 months after infection with SARS-CoV-2 and 3 months after vaccination. Our primary outcome was a binary indicator of changes in the menstrual cycle. We used multivariate regression analysis to identify factors associated with menstrual changes.

RESULTS

We received 1012 completed questionnaires and 735 (72.7%) were from women aged between 20 and 39 years, 745 (73.6%) were White and 491 (48.6%) lived with a partner. A total of 419 (41.6%) of the women reported SARS-CoV-2 infection; however, only two of them were hospitalized, and 995 (98.8%) of women had at least one dose of COVID-19 vaccine. About menstrual characteristics, 170 (41.3%) reported changes after having COVID-19 and 294 (29.9%) after COVID-19 vaccination, respectively. Few years of schooling, lower income, and non-white ethnicity were related to higher reports of menstrual changes after COVID-19. Menstrual changes after COVID-19 vaccination were associated with not using contraception. Higher body mass index was associated with irregularities in cyclicity and bleeding days, after COVID-19 and COVID-19 vaccination, respectively.

CONCLUSION

Our results corroborated the stability of the menstrual cycle after having COVID-19 or COVID-19 vaccination; however, there is a potential relationship between menstrual changes and socioeconomic factors as well as contraceptive use.

Prolongation of the Menstrual Cycle After Receipt of the Primary Series and Booster Doses of mRNA Coronavirus Disease 2019 (COVID-19) Vaccination

OBJECTIVE

To quantitatively evaluate the effect of a booster vaccination dose against coronavirus disease 2019 (COVID-19) on menstrual cycle in a large-scale retrospective cohort study using a menstrual cycle tracking smartphone application (app).

METHODS

Prospectively or retrospectively recorded data, including the start and finish dates of menstrual cycles, were collected with the app. Detailed data on vaccinations, side effects, and participants' characteristics were retrospectively collected from a questionnaire on the app. For each COVID-19 vaccination shot (first, second, and third), within-individual changes in menstrual cycle length up to the fourth postvaccination cycle were evaluated.

RESULTS

Among the 7,376 and 6,873 participants who had the first and second COVID-19 vaccine doses in different menstrual cycles, respectively, menstrual cycles immediately after the vaccination (first postvaccination cycles) were an average of 0.22 days (95% CI, 0.06-0.39) and 0.37 days (95% CI, 0.20-0.54) longer than the prevaccination cycle. In contrast, among the 1,672 participants who received the first and second doses in the same cycle, the first postvaccination cycle was an average of 4.21 days (95% CI, 3.69-4.72) longer. The second to fourth postvaccination cycles returned to the level of the prevaccination cycle. However, among the 4,768 participants who had the third COVID-19 vaccine dose, the menstrual cycle immediately after the vaccination was an average of 1.20 days (95% CI, 1.00-1.40) longer, with prolongation of cycles of 0.27 days (95% CI, 0.10-0.44) to 0.41 days (95% CI, 0.22-0.59) persisting from the second to the fourth postvaccination cycle.

CONCLUSION

The booster shot against COVID-19 may have a greater and longer-lasting effect on menstrual cycles than the primary-series shots. Although the effect size was small, evidence on the side effects of immunization on menstruation should be accumulated.

COVID-19 vaccine boosters for young adults: a risk benefit assessment and ethical analysis of mandate policies at universities

In 2022, students at North American universities with third-dose COVID-19 vaccine mandates risk disenrolment if unvaccinated. To assess the appropriateness of booster mandates in this age group, we combine empirical risk-benefit assessment and ethical analysis. To prevent one COVID-19 hospitalisation over a 6-month period, we estimate that 31 207-42 836 young adults aged 18-29 years must receive a third mRNA vaccine. Booster mandates in young adults are expected to cause a net harm: per COVID-19 hospitalisation prevented, we anticipate at least 18.5 serious adverse events from mRNA vaccines, including 1.5-4.6 booster-associated myopericarditis cases in males (typically requiring hospitalisation). We also anticipate 1430-4626 cases of grade ≥3 reactogenicity interfering with daily activities (although typically not requiring hospitalisation). University booster mandates are unethical because they: (1) are not based on an updated (Omicron era) stratified risk-benefit assessment for this age group; (2) may result in a net harm to healthy young adults; (3) are not proportionate: expected harms are not outweighed by public health benefits given modest and transient effectiveness of vaccines against transmission; (4) violate the reciprocity principle because serious vaccine-related harms are not reliably compensated due to gaps in vaccine injury schemes; and (5) may result in wider social harms. We consider counterarguments including efforts to increase safety on campus but find these are fraught with limitations and little scientific support. Finally, we discuss the policy relevance of our analysis for primary series COVID-19 vaccine mandates.

Prevalence of menstrual irregularities after coronavirus disease 2019 vaccination: A cross-sectional study in the Eastern Province, Saudi Arabia

BACKGROUND

Reports indicate that there are menstrual cycle disturbances following coronavirus disease 2019 (COVID-19) vaccination. The present study explored the prevalence of menstrual irregularities after COVID-19 vaccination and the association of menstrual irregularities with vaccine type, doses, immediate adverse effects, history of COVID-19 infection, and its severity.

MATERIALS AND METHODS

For this cross-sectional study, 406 women of reproductive age completed an online survey about the postvaccine changes in their menstruation (cycle duration, bleeding days, and bleeding amount), COVID-19 vaccine history (doses, type of vaccine, and immediate adverse effects), history of COVID-19 infection, and its severity. Data was analyzed using SPSS; descriptive statistics were computed and Chi-square test, and binary logistic regression analysis were performed.

RESULTS

Of the total 406 women, 45% reported postvaccine changes in their menstrual cycle. The most common menstrual change was increased dysmenorrhea (68%), followed by an increase in the length of the cycle (52%). There was a significant association between postvaccine menstrual changes and the age, marital status, and family history of menstrual irregularities. No association was observed between postvaccine menstrual changes and COVID-19 vaccine-and COVID-19 infection-related variables. As per the best-fit model of our predictors, the odds of having postvaccine menstrual changes were 0.41 times less in "single" women (confidence interval [CI] = 0.26-0.27; P < 0.001) and 1.714 times greater in women who had a "family history of menstrual irregularities" (CI = 1.092-2.690; P = 0.02), respectively.

CONCLUSION

A substantial number of women complained of postvaccine menstrual changes regardless of their age, type of COVID-19 vaccine, doses, immediate adverse effects, and COVID-19 infection history/severity. Being "single" decreased the probability, whereas having a family history of menstrual irregularities increased the probability significantly of having postvaccine menstrual changes.

Associations Among Menstrual Cycle Length, Coronavirus Disease 2019 (COVID-19), and Vaccination

OBJECTIVE

To assess whether coronavirus disease 2019 (COVID-19) is associated with menstrual cycle length changes and, if so, how that compares with those undergoing vaccination or no event (control).

METHODS

We conducted a retrospective cohort analysis in which we analyzed prospectively tracked cycle-length data from users of a period tracker application who also responded to a survey regarding COVID-19 symptoms and vaccination. We restricted our sample to users aged 16-45 years, with normal cycle lengths (24-38 days) and regular tracking behavior during the five cycles around COVID-19 symptoms or vaccination or a similar time period for those experiencing no event (control group). We calculated the within-user change in cycle length (days) from the three consecutive cycles preevent average (either vaccination, disease, or neither; cycles 1-3) to the event (cycle 4) and postevent (cycle 5) cycles. We used mixed-effects models to estimate the age- and country-adjusted difference in change in cycle length across the groups.

RESULTS

We included 6,514 users from 110 countries representing 32,570 cycles (COVID-19 symptoms: 1,450; COVID-19 vaccination: 4,643; control: 421). The COVID-19 cohort experienced a 1.45-day adjusted increase in cycle length during cycle 4 (COVID-19) compared with their three preevent cycles (95% CI 0.86-2.04). The vaccinated group experienced a 1.14-day adjusted increase in cycle length during cycle 4 (COVID-19 vaccine) compared with their preevent average (95% CI 0.60-1.69). The control group (neither vaccine nor disease) experienced a 0.68-day decrease (95% CI -1.18 to -0.19) in a similar time period. Post hoc tests showed no significant differences in the magnitude of changes between the COVID-19 and vaccination cohorts. In both cohorts, cycle length changes disappeared in the postevent cycle.

CONCLUSION

Experiencing COVID-19 is associated with a small change in cycle length similar to COVID-19 vaccination. These changes resolve quickly within the next cycle.

Postmenopausal bleeding after COVID-19 vaccination

BACKGROUND

There is a growing literature base regarding menstrual changes following COVID-19 vaccination among premenopausal people. However, relatively little is known about uterine bleeding in postmenopausal people following COVID-19 vaccination.

OBJECTIVE

This study aimed to examine trends in incident postmenopausal bleeding diagnoses over time before and after COVID-19 vaccine introduction, and to describe cases of new-onset postmenopausal bleeding after COVID-19 vaccination.

STUDY DESIGN

For postmenopausal bleeding incidence calculations, monthly population-level cohorts consisted of female Kaiser Permanente Northwest members aged ≥45 years. Those diagnosed with incident postmenopausal bleeding in the electronic medical record were included in monthly numerators. Members with preexisting postmenopausal bleeding or abnormal uterine bleeding, or who were at increased risk of bleeding due to other health conditions, were excluded from monthly calculations. We used segmented regression analysis to estimate changes in the incidence of postmenopausal bleeding diagnoses from 2018 through 2021 in Kaiser Permanente Northwest members meeting the inclusion criteria, stratified by COVID-19 vaccination status in 2021. In addition, we identified all members with ≥1 COVID-19 vaccination between December 14, 2020 and August 14, 2021, who had an incident postmenopausal bleeding diagnosis within 60 days of vaccination. COVID-19 vaccination, diagnostic procedures, and presumed bleeding etiology were assessed through chart review and described. A temporal scan statistic was run on all cases without clear bleeding etiology.

RESULTS

In a population of 75,530 to 82,693 individuals per month, there was no statistically significant difference in the rate of incident postmenopausal bleeding diagnoses before and after COVID-19 vaccine introduction (P=.59). A total of 104 individuals had incident postmenopausal bleeding diagnosed within 60 days following COVID-19 vaccination; 76% of cases (79/104) were confirmed as postvaccination postmenopausal bleeding after chart review. Median time from vaccination to bleeding onset was 21 days (range: 2-54 days). Among the 56 postmenopausal bleeding cases with a provider-attributed etiology, the common causes of bleeding were uterine or cervical lesions (50% [28/56]), hormone replacement therapy (13% [7/56]), and proliferative endometrium (13% [7/56]). Among the 23 cases without a clear etiology, there was no statistically significant clustering of postmenopausal bleeding onset following vaccination.

CONCLUSION

Within this integrated health system, introduction of COVID-19 vaccines was not associated with an increase in incident postmenopausal bleeding diagnoses. Diagnosis of postmenopausal bleeding in the 60 days following receipt of a COVID-19 vaccination was rare.

No one listens to us, we know this, so we participated: Qualitative evidence from menstruation research during the COVID-19 pandemic

BACKGROUND

We created a survey to assess menstrual side effects after COVID-19 vaccination when we noticed news stories that denied or discounted the experiences of tens of thousands of menstruating and formerly menstruating people who reported experiencing bleeding changes. This survey had an unprecedented response hundreds of times higher than we had anticipated (n = 101,824).

OBJECTIVES

We investigated what motivated our sample to participate without remuneration to understand both general motivations for survey participation as well as why this survey captured the interest of so many.

DESIGN

We used open-ended responses from our online, mixed-method survey collected from April to October 2021.

METHODS

Using computer-assisted qualitative data analysis tools in R, we conducted a thematic analysis on open-ended responses. We used topic modeling to cluster the data, synthesize responses across 22,737 participants, and inform the themes summarizing the responses to "What is your interest in this project?" We compared and contrasted responses across groups (racial identity, ethnicity, gender) to examine whether the themes were representative across the demographic groups in our study.

RESULTS

The themes that characterized participants' interest in participating were vaccine effects and women's/people's health, personal experience related to the vaccine, and a love for science and data. We compared responses among demographic subgroups to avoid an overfocus on majority group responses and found the themes were reflected across each group. Lastly, we found our themes reflected multiple types of altruism.

CONCLUSION

These results were important in showing how emergent research that focuses on the concerns of potential participants can encourage high response rates from both marginalized and majority communities. Inclusive practices and familiarity with the research team built credibility that engendered trust with the public.

The Relationship Between Menstrual Cycle Irregularities and COVID-19 Vaccination

Background After COVID-19 vaccination, females reported irregularities and changes in their menstrual cycle. We aimed to explore the menstrual irregularities following COVID-19 vaccination in Saudi women of childbearing age. Methodology The study was a cross-sectional study conducted among women in Riyadh, Saudi Arabia, who had no history of menstrual irregularities before receiving the first dose of the COVID-19 vaccine. The participants filled out an online self-administered questionnaire via Google Form about any menstrual irregularities they experienced after receiving the COVID-19 vaccine. Results A total of 535 participants completed the survey. The study found that 41.7% (223) of women experienced menstrual changes after the first dose of the COVID-19 vaccine, increasing to 44.1% (236) after the second dose. The incidence of these changes varied between the first and second doses. For example, the incidence of changes in period duration decreased from 51.6% to 48.3% after the first and second doses, respectively. Similarly, the incidence of delayed periods decreased from 48.4% to 47.9%, while dysmenorrhea increased slightly from 30.9% to 32.2% after the two doses. The incidence of heavier menstrual flow increased from 26.9% to 30.5%, while the incidence of lighter menstrual flow decreased from 26.9% to 24.6% after the first and second doses, respectively. Conclusions There is an increased incidence of changes in menstrual cycle after COVID-19 vaccination, particularly in menstrual cycle length, menstrual pain, and the flow of menstruation. Future studies are needed to investigate the potential underlying biological mechanisms.

Impact of COVID-19 Vaccinations on Menstrual Bleeding

INTRODUCTION

Vaccination has a fundamental role in protecting against and modifying the severity of several infectious diseases, including COVID-19. Several immune and non-immune adverse events have been reported post-COVID-19 vaccine. The aim of this study was to assess the effect of the COVID-19 vaccine on women's menstrual bleeding.

METHODS

A cross-sectional study was conducted among 399 vaccinated women in the Eastern Province of Saudi Arabia. Data were collected using a direct interview-based questionnaire including four sections.

RESULTS

A total of 399 women were recruited, with a mean age of 25.54 ± 6.177 years. More than half (53.9%) of the participants reported post-vaccination menstrual bleeding abnormality in terms of a heavy or irregular cycle. Out of the total number, 40 (21.4%) women reported having heavy menstrual flow, and 67 (16.8%) had non-menstrual bleeding after receiving the COVID-19 vaccine. Fully vaccinated women were at a greater risk of post-vaccination menstrual bleeding abnormality (p = 0.058). However, there was no correlation between booster shot type and menstrual bleeding abnormality (p > 0.05). In addition, there was no significant association between non-menstrual bleeding and the type of booster shot, the type of the first dose, and prior history of COVID-19 infection (p > 0.05).

CONCLUSION

Despite vaccination being the most effective way to prevent COVID-19, it does have an impact on menstrual bleeding in terms of menorrhagia and metrorrhagia. Therefore, more studies are needed to understand the mechanism and the long-term impact of COVID-19 vaccines on the hemostatic system.

Menstrual abnormalities after COVID-19 vaccination in the Netherlands: A description of spontaneous and longitudinal patient-reported data

AIMS

During the COVID-19 vaccination campaigns, the number of reports of menstrual abnormalities increased rapidly. Here, we describe the nature and potential risk factors associated with menstrual abnormalities based on spontaneously reporting data as well as data from a prospective cohort event monitoring (CEM) study as these are poorly studied.

METHODS

Reports of menstrual abnormalities received by the Netherlands Pharmacovigilance Centre Lareb in the spontaneous reporting system between February 2021 and April 2022 were summarized. In addition, logistic regression analysis was performed on the reported menstrual abnormalities in the CEM study to assess the association between person characteristics, prior SARS-CoV-2 infection and use of hormonal contraceptives and the occurrence of menstrual abnormalities after vaccination.

RESULTS

We analysed over 24 000 spontaneous reports of menstrual abnormalities and over 500 episodes (among 16 929 included women) of menstrual abnormalities in the CEM study. The CEM study showed an incidence of 41.4 per 1000 women aged ≤54 years. Amenorrhoea/oligomenorrhoea and heavy menstrual bleeding collectively accounted for about half of all abnormalities reported. Significant associations were observed for the age group 25-34 years (odds ratio 2.18; 95% confidence interval 1.45-3.41) and the Pfizer vaccine (odds ratio 3.04; 95% confidence interval 2.36-3.93). No association was observed for body mass index and presence of most comorbidities assessed.

CONCLUSION

The cohort study showed a high incidence of menstrual disorders among women aged ≤54 years, and this observation was supported by the analysis of spontaneous reports. This suggests that a relation between COVID-19 vaccination and menstrual abnormalities is plausible and should be further investigated.

Unexpected vaginal bleeding and COVID-19 vaccination in nonmenstruating women

The association between coronavirus disease 2019 (COVID-19) vaccination and vaginal bleeding among nonmenstruating women is not well studied. The Norwegian Institute of Public Health followed several cohorts throughout the pandemic and early performed a systematic data collection of self-reported unexpected vaginal bleeding in nonmenstruating women. Among 7725 postmenopausal women, 7148 perimenopausal women, and 7052 premenopausal women, 3.3, 14.1, and 13.1% experienced unexpected vaginal bleeding during a period of 8 to 9 months, respectively. In postmenopausal women, the risk of unexpected vaginal bleeding (i.e., postmenopausal bleeding) in the 4 weeks after COVID-19 vaccination was increased two- to threefold, compared to a prevaccination period. The corresponding risk of unexpected vaginal bleeding after vaccination was increased three- to fivefold in both nonmenstruating peri- and premenopausal women. In the premenopausal women, Spikevax was associated with at 32% increased risk as compared to Comirnaty. Our results must be confirmed in future studies.

Prevalence of and risk factors for self-reported menstrual changes following COVID-19 vaccination: a Danish cohort study

STUDY QUESTION

Are there some characteristics that render individuals more susceptible to report menstrual changes following the Coronavirus disease 2019 (COVID-19) vaccination?

SUMMARY ANSWER

We found that 30% of menstruating women reported menstrual changes following COVID-19 vaccination and several potential risk factors including stress, vaccine concerns, severe COVID-19 infection, and immediate vaccine symptoms were associated with these reports.

WHAT IS KNOWN ALREADY

Studies suggest that COVID-19 vaccination might temporarily prolong menstrual cycle length by less than 1 day. Specific characteristics may trigger menstrual changes in temporal relation to the vaccination simply by chance or render women more vigilant to potential menstrual changes after being vaccinated. However, research investigating potential risk factors for reporting menstrual changes following COVID-19 vaccination is limited.

STUDY DESIGN, SIZE, DURATION

A population-based Danish cohort study. Data were collected from May 2021 to December 2021 as a part of the BiCoVac Cohort with the aim of examining non-specific effects following COVID-19 vaccination. The main study population included 13 648 menstruating women aged 16-65 years who completed all surveys, received their first dose of a COVID-19 vaccine during the data collection period, and completed questions related to their menstrual cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Potential risk factors included 14 biological, physical, or psychological measures. Information on most potential risk factors was self-reported and collected before the participants' first COVID-19 vaccination. Information about any menstrual change following COVID-19 vaccination was self-reported at the end of the data collection period. Logistic regression analyses were used to estimate crude and adjusted odds ratios (ORs) with 95% CIs for the association between each potential risk factor and reporting menstrual changes following COVID-19 vaccination.

MAIN RESULTS AND THE ROLE OF CHANCE

Any menstrual change following COVID-19 vaccination was reported by 30% of menstruating women. Most of the potential risk factors were associated with reports of menstrual changes following COVID-19 vaccination. In particular, higher odds were found among women who reported ≥5 immediate vaccine symptoms; OR 1.67 [1.50-1.86], had had a prior severe COVID-19 infection; OR 2.17 [1.40-3.35], had a high-stress level at baseline; OR 1.67 [1.32-2.10], or were concerned about COVID-19 vaccines prior to vaccination; OR 1.92 [1.50-2.45]. Lower odds were found among women with regular menstrual cycles using hormonal contraception; OR 0.71 [0.65-0.78].

LIMITATIONS, REASONS FOR CAUTION

We were unable to address the causal effect of COVID-19 vaccination on the reported menstrual changes, as information about menstrual changes was not available among non-vaccinated women.

WIDER IMPLICATIONS OF THE FINDINGS

The study identified several potential risk factors for reporting menstrual changes following COVID-19 vaccination. Further studies are needed to establish causal associations and the clinical impact of self-reported menstrual changes.

STUDY FUNDING/COMPETING INTEREST(S)

The BiCoVac data collection was funded by TrygFonden (id-number: 153678). No competing interests are declared.

TRIAL REGISTRATION NUMBER

N/A.

Identifying a causal link between prolactin signaling pathways and COVID-19 vaccine-induced menstrual changes

COVID-19 vaccines have been instrumental tools in the fight against SARS-CoV-2 helping to reduce disease severity and mortality. At the same time, just like any other therapeutic, COVID-19 vaccines were associated with adverse events. Women have reported menstrual cycle irregularity after receiving COVID-19 vaccines, and this led to renewed fears concerning COVID-19 vaccines and their effects on fertility. Herein we devised an informatics workflow to explore the causal drivers of menstrual cycle irregularity in response to vaccination with mRNA COVID-19 vaccine BNT162b2. Our methods relied on gene expression analysis in response to vaccination, followed by network biology analysis to derive testable hypotheses regarding the causal links between BNT162b2 and menstrual cycle irregularity. Five high-confidence transcription factors were identified as causal drivers of BNT162b2-induced menstrual irregularity, namely: IRF1, STAT1, RelA (p65 NF-kB subunit), STAT2 and IRF3. Furthermore, some biomarkers of menstrual irregularity, including TNF, IL6R, IL6ST, LIF, BIRC3, FGF2, ARHGDIB, RPS3, RHOU, MIF, were identified as topological genes and predicted as causal drivers of menstrual irregularity. Our network-based mechanism reconstruction results indicated that BNT162b2 exerted biological effects similar to those resulting from prolactin signaling. However, these effects were short-lived and didn't raise concerns about long-term infertility issues. This approach can be applied to interrogate the functional links between drugs/vaccines and other side effects.

Pharmacovigilance signals from active surveillance of mRNA platform vaccines (tozinameran and elasomeran)

INTRODUCTION

Two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines, tozinameran/BNT162b2 (Comirnaty®, Pfizer-BioNTech) and elasomeran/mRNA-1273 (Spikevax®, Moderna), were approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) at the end of 2020, less than a year after the start of the coronavirus disease 2019 (COVID-19) pandemic. In France, the health authorities have requested an intensive vaccination campaign, accompanied by a reinforced and active pharmacovigilance surveillance. This surveillance and analysis of real-life data, based on spontaneous reports received by the French Network of Regional PharmacoVigilance Centers (RFCRPV), has enabled to identify numerous pharmacovigilance signals. Some of them, such as myocarditis and heavy menstrual bleeding, have been confirmed as adverse effects of these vaccines.

METHOD

We propose a descriptive review of the main pharmacovigilance signals identified by the RFCRPV concerning vaccines from the mRNA platform.

RESULTS

Most pharmacovigilance signals were common to both mRNA vaccines: myocarditis, menstrual disorders, acquired haemophilia, Parsonage-Turner syndrome, rhizomelic pseudo-polyarthritis and hearing disorders. Other signals were more specific, such as arterial hypertension with tozinameran or delayed reaction site injection with elasomeran.

CONCLUSION

This non-exhaustive review illustrates the experience of RFCRPV in identifying and monitoring pharmacovigilance signals related to mRNA vaccines in France during the COVID-19 pandemics, and the crucial role of pharmacological and clinical expertise in this area. It also highlights the predominant contribution of spontaneous reporting in the generation of pharmacovigilance signals, particularly for serious and rare adverse events not detected before marketing.

Why we must fight ignorance about COVID-19 vaccines and menstrual cycles

The COVID-19 pandemic has revealed a critical gap in female health science, fueling anxiety, polarized views, and vaccine hesitancy. Although menstrual cycles feel like a niche topic for some, efforts to augment knowledge on the 'fifth vital sign' experienced by more than 300 million people on any given day worldwide are crucial to promote gender equity in health.

Heavy bleeding and other menstrual disturbances in young women after COVID-19 vaccination

BACKGROUND

Many signals of menstrual disturbances as possible side effects of vaccination against COVID-19 have been reported. Our objective was to compare the risk of menstrual disturbances before and after vaccination among women aged 18-30 years in Oslo, Norway.

METHODS

We used electronic questionnaires to collect reports of menstrual disturbances from 3972 women aged 18-30 years, participating in the population-based Norwegian Young Adult Cohort. We examined the occurrence of menstrual disturbances (heavier bleeding than usual, prolonged bleeding, shorter interval between menstruations, longer interval between menstruations, spot bleedings, stronger pain during menstruation, period pain without bleeding) before and after the first and second dose of COVID-19 vaccine. Relative risks (RR) according to vaccination were estimated using a self-controlled case-series design. We performed additional analyses stratified by vaccine brand, contraception/hormone use, and presence of gynecological condition(s).

RESULTS

The prevalence of any menstrual disturbance was 36.7 % in the last menstrual cycle prior the first vaccine dose. The RR for heavier bleeding than usual was 1.90 (95 % CI: 1.69-2.13) after the first vaccine dose and 1.84 (95 % CI 1.66-2.03) after the second dose. Increased risks of prolonged bleeding, shorter interval between menstruations, and stronger pain during menstruation were also observed after both doses. The RRs did not differ with vaccine brand, contraception/hormone use, or presence of gynecological condition(s) for any of the menstrual disturbances.

CONCLUSION

Menstrual disturbances were common regardless of vaccination. We found increased risk of menstrual disturbances after vaccination, particularly for heavier bleeding than usual, prolonged bleeding, shorter interval between menstruations, and stronger period pain. In the future, menstrual characteristics should be included in vaccine trials.

COVID-19 vaccination and menstrual cycle characteristics: A prospective cohort study

We prospectively examined the association between COVID-19 vaccination and menstrual cycle characteristics in an internet-based prospective cohort study. We included a sample of 1,137 participants who enrolled in Pregnancy Study Online (PRESTO), a preconception cohort study of couples trying to conceive, during January 2021-August 2022. Eligible participants were aged 21-45 years, United States or Canadian residents, and trying to conceive without fertility treatment. At baseline and every 8 weeks for up to 12 months, participants completed questionnaires on which they provided information on COVID-19 vaccination and menstrual cycle characteristics, including cycle regularity, cycle length, bleed length, heaviness of bleed, and menstrual pain. We fit generalized estimating equation (GEE) models with a log link function and Poisson distribution to estimate the adjusted risk ratio (RR) for irregular cycles associated with COVID-19 vaccination. We used linear regression with GEE to estimate adjusted mean differences in menstrual cycle length associated with COVID-19 vaccination. We adjusted for sociodemographic, lifestyle, medical and reproductive factors. Participants had 1.1 day longer menstrual cycles after receiving the first dose of COVID-19 vaccine (95 % CI: 0.4, 1.9) and 1.3 day longer cycles after receiving the second dose (95 % CI: 0.2, 2.5). Associations were attenuated at the second cycle post-vaccination. We did not observe strong associations between COVID-19 vaccination and cycle regularity, bleed length, heaviness of bleed, or menstrual pain. In conclusion, COVID-19 vaccination was associated with a ∼1 day temporary increase in menstrual cycle length, but was not appreciably associated with other menstrual cycle characteristics.

Association between SARS-CoV-2 vaccination and healthcare contacts for menstrual disturbance and bleeding in women before and after menopause: nationwide, register based cohort study

OBJECTIVES

To evaluate the risks of any menstrual disturbance and bleeding following SARS-CoV-2 vaccination in women who are premenopausal or postmenopausal.

DESIGN

A nationwide, register based cohort study.

SETTING

All inpatient and specialised outpatient care in Sweden from 27 December 2020 to 28 February 2022. A subset covering primary care for 40% of the Swedish female population was also included.

PARTICIPANTS

2 946 448 Swedish women aged 12-74 years were included. Pregnant women, women living in nursing homes, and women with history of any menstruation or bleeding disorders, breast cancer, cancer of female genital organs, or who underwent a hysterectomy between 1 January 2015 and 26 December 2020 were excluded.

INTERVENTIONS

SARS-CoV-2 vaccination, by vaccine product (BNT162b2, mRNA-1273, or ChAdOx1 nCoV-19 (AZD1222)) and dose (unvaccinated and first, second, and third dose) over two time windows (one to seven days, considered the control period, and 8-90 days).

MAIN OUTCOME MEASURES

Healthcare contact (admission to hospital or visit) for menstrual disturbance or bleeding before or after menopause (diagnosed with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes N91, N92, N93, N95).

RESULTS

2 580 007 (87.6%) of 2 946 448 women received at least one SARS-CoV-2 vaccination and 1 652 472 (64.0%) 2 580 007 of vaccinated women received three doses before the end of follow-up. The highest risks for bleeding in women who were postmenopausal were observed after the third dose, in the one to seven days risk window (hazard ratio 1.28 (95% confidence interval 1.01 to 1.62)) and in the 8-90 days risk window (1.25 (1.04 to 1.50)). The impact of adjustment for covariates was modest. Risk of postmenopausal bleeding suggested a 23-33% increased risk after 8-90 days with BNT162b2 and mRNA-1273 after the third dose, but the association with ChAdOx1 nCoV-19 was less clear. For menstrual disturbance or bleeding in women who were premenopausal, adjustment for covariates almost completely removed the weak associations noted in the crude analyses.

CONCLUSIONS

Weak and inconsistent associations were observed between SARS-CoV-2 vaccination and healthcare contacts for bleeding in women who are postmenopausal, and even less evidence was recorded of an association for menstrual disturbance or bleeding in women who were premenopausal. These findings do not provide substantial support for a causal association between SARS-CoV-2 vaccination and healthcare contacts related to menstrual or bleeding disorders.

Female reproductive health impacts of Long COVID and associated illnesses including ME/CFS, POTS, and connective tissue disorders: a literature review

Long COVID disproportionately affects premenopausal women, but relatively few studies have examined Long COVID's impact on female reproductive health. We conduct a review of the literature documenting the female reproductive health impacts of Long COVID which may include disruptions to the menstrual cycle, gonadal function, ovarian sufficiency, menopause, and fertility, as well as symptom exacerbation around menstruation. Given limited research, we also review the reproductive health impacts of overlapping and associated illnesses including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), connective tissue disorders like Ehlers-Danlos syndrome (EDS), and endometriosis, as these illnesses may help to elucidate reproductive health conditions in Long COVID. These associated illnesses, whose patients are 70%-80% women, have increased rates of dysmenorrhea, amenorrhea, oligomenorrhea, dyspareunia, endometriosis, infertility, vulvodynia, intermenstrual bleeding, ovarian cysts, uterine fibroids and bleeding, pelvic congestion syndrome, gynecological surgeries, and adverse pregnancy complications such as preeclampsia, maternal mortality, and premature birth. Additionally, in Long COVID and associated illnesses, symptoms can be impacted by the menstrual cycle, pregnancy, and menopause. We propose priorities for future research and reproductive healthcare in Long COVID based on a review of the literature. These include screening Long COVID patients for comorbid and associated conditions; studying the impacts of the menstrual cycle, pregnancy, and menopause on symptoms and illness progression; uncovering the role of sex differences and sex hormones in Long COVID and associated illnesses; and addressing historical research and healthcare inequities that have contributed to detrimental knowledge gaps for this patient population.

Adverse effects, perceptions and attitudes related to BNT162b2, mRNA-1273 or JNJ-78436735 SARS-CoV-2 vaccines: Population-based cohort

Long-term control of SARS-CoV-2 requires effective vaccination strategies. This has been challenged by public mistrust and the spread of misinformation regarding vaccine safety. Better understanding and communication of the longer-term and comparative experiences of individuals in the general population following vaccination are required. In this population-based longitudinal study, we included 575 adults, randomly selected from all individuals presenting to a Swiss reference vaccination center, for receipt of BNT162b2, mRNA1273, or JNJ-78436735. We assessed the prevalence, onset, duration, and severity of self-reported adverse effects over 12 weeks following vaccination. We additionally evaluated participants' perceptions of vaccines, trust in public health authorities and pharmaceutical companies, and compliance with public health measures. Most participants reported at least one adverse effect within 12 weeks following vaccination. Adverse effects were mostly mild or moderate, resolved within three days, and rarely resulted in anaphylaxis or hospitalizations. Female sex, younger age, higher education, and receipt of mRNA-1273 were associated with reporting adverse effects. Compared to JNJ-78436735 recipients, a higher proportion of mRNA vaccine recipients agreed that vaccination is important, and trusted public health authorities. Our findings provide real-world estimates of the prevalence of adverse effects following SARS-CoV-2 vaccination and highlight the importance of transparent communication to ensure the success of current or future vaccination campaigns.