Effect of COVID-19 vaccination on menstrual periods in a prospectively recruited cohort

Abstract

COVID-19 vaccination protects against the potentially serious consequences of SARS-CoV2 infection, but some people have been hesitant to receive the vaccine because of reports that it could affect menstrual bleeding. To determine whether this occurs, we prospectively recruited a cohort of 79 individuals, each of whom recorded details of at least three consecutive menstrual cycles, during which time they each received at least one dose of COVID-19 vaccine. We find that either dose of the COVID-19 vaccine is associated with a delay to the subsequent period in spontaneously cycling participants (2.3 days after dose 1; 1.3 days after dose 2) but this change rapidly reverses. No change to timing was detected in those on hormonal contraception. We detected no change in menstrual flow associated with either dose of the vaccine, in either spontaneously cycling participants or those on hormonal contraception. We detected no association between menstrual changes and other commonly-reported side effects of vaccination, such as sore arm, fever and fatigue.

What Do We Know About Abnormal Uterine Bleeding Following Vaccination Against Covid-19 After Two and A Half Years Of Experience? A Systematic Review and Meta- Analysis

“…The current study estimates that there is abnormal uterine bleeding after vaccination in almost one-third of vaccinated females. Individual studies also report that this is transient and mild [31][32][33][34][35][36]. The current analysis found no speci c vaccine manufacturer to in uence the abnormal bleeding rate.…”

“…Emerging evidence suggests that abnormal uterine bleeding is short lasting, not requiring treatment or hospitalization [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Nevertheless, abnormal uterine bleeding disrupts daily tasks, hindering normal activities and inducing associated stress.…”

Menstrual irregularities and vaginal bleeding after COVID-19 vaccination reported to v-safe active surveillance, USA in December, 2020–January, 2022: an observational cohort study

“…A link between COVID-19 vaccination and menstruation is biologically plausible. Although one retrospective study (published as a preprint) examining menstrual cycle records did not detect a link between COVID-19 vaccination and menstrual changes, 5 a study using prospectively tracked menstrual cycle data showed that COVID-19 vaccination is associated with a less than 1-day increase in menstrual cycle length. 12 The process of menstruation, in which endometrial tissue proliferates and breaks down in the absence of egg fertilisation and implantation, is regulated by complex interactions between hormones, inflammation pathways, tissues, and cells.…”

“…There have been reports about menstrual irregularities and vaginal bleeding occurring after COVID-19 vaccination in social and traditional media, the Vaccine Adverse Event Reporting System, vaccine monitoring systems in the UK and Norway, and online surveys. 5 , 6 , 7 , 8 , 9 Symptoms related to menstruation and vaginal bleeding were not solicited adverse events in clinical trials of COVID-19 vaccines, and they were not solicited as prespecified symptoms in v-safe, a voluntary active surveillance system monitoring health status after COVID-19 vaccination in the USA. 10 In August, 2021, the National Institutes of Health announced funding of research studies exploring potential links between COVID-19 vaccination and menstruation.…”

Menstrual changes after COVID-19 vaccination among menstruators of reproductive age: A cross- sectional study from Erbil City, Iraq

“…Recent studies conducted in various countries have suggested potential associations between COVID-19 vaccination and menstrual changes. For instance, several studies have reported an increased prevalence of menstrual irregularities and changes in menstrual patterns, such as alterations in cycle length and flow volume, following COVID-19 vaccination [8][9][10][11][12][13]. However, these studies were conducted in different settings and populations.…”