Does COVID Vaccination Really Lead to Wonky Periods

— Swedish research study discovers weak spot in between vaccination and health care check outs for menstrual disruption

by Rachael Robertson, Enterprise & & Investigative Writer, MedPage Today

Weak associations were observed in between vaccination for COVID-19 and health care contacts associated with menstrual disruption or bleeding conditions in females prior to and after menopause, according to a Swedish register-based accomplice research study.

Taking a look at over 2.5 million females who got a minimum of one dosage of COVID vaccine, the greatest association for menstrual disruption observed was an adjusted 26% increased danger amongst females ages 12 to 49 in the 1-7 days danger window after the very first dosage (HR 1.26, 95% CI 1.11-1.42), reported Rickard Ljung, MD, PhD, MPH, of the Swedish Medical Products Agency in Uppsala and the Karolinska Institutet in Stockholm, and coworkers.

For premenopausal bleeding, just non-significant associations were observed– a 14% increased danger in the 1-7 days danger window after the very first and 3rd dosages.

Amongst postmenopausal females, the greatest dangers for bleeding were observed after the 3rd dosage, both in the 1-7 days danger window (HR 1.28, 95% CI 1.01-1.62) and in the 8-90 days danger window (HR 1.25, 95% CI 1.04-1.50), according to the findings in The BMJ

There was a 23% to 33% increased threat of postmenopausal bleeding after 8-90 days with the Pfizer-BioNTech vaccine, and with the Moderna vaccine after the 3rd dosage, however the association with the Oxford-AstraZeneca vaccine was less clear.

“Weak and irregular associations were observed in between SARS-CoV-2 vaccination and health care contacts for bleeding in females who are postmenopausal, and even less proof was taped of an association for menstrual disruption or bleeding in ladies who were premenopausal,” Ljung and co-authors concluded. “These findings do not supply significant assistance for a causal association in between SARS-CoV-2 vaccination and health care contacts associated with menstrual or bleeding conditions.”

Ljung informed MedPage Today that “it’s crucial to keep in mind that we do not state that ladies do not experience these conditions. What we do state is that even if they experience them, they do not appear to be so serious that a female will look for medical attention for these issues.”

“There are a great deal of spontaneous reports from ladies all around the world who have actually reported thought unfavorable occasions to their drug companies,” he included. “And in Sweden, we have 1,000 of those reports where females have actually reported that they believe an unfavorable occasion of menstrual conditions or bleeding after vaccination– however that’s self-reported information to the companies.”

Other research studies have actually revealed that ladies have actually reported a little longer menstruations following COVID vaccination, and others have actually reported modifications in menstrual signs after COVID infection.

Becky Smullin Dawson, MPH, PhD, of Allegheny College in Meadville, Pennsylvania, informed MedPage Today that the research study checks packages for extensive, legitimate, and dependable information that consisted of extremely little loss to follow-up in a big accomplice. Her bookings come from the real concerns the research study looked for to address.

“The obstacle that I’m dealing with today is that the important things that they were searching for, like irregular bleeding in females who menstruate– that’s not something that the majority of us go to a medical professional for,” stated Dawson, who was not included with the research study.

She explained that the research study does not respond to the better concern of whether the COVID vaccine and boosters increase or trigger menstrual disruption, and why.

“Should we be making choices or making conclusions about the effect of the vaccine simply taking a look at health care records for something that I do not believe a great deal of females go to health care centers for?” Dawson stated. “I do not believe [this study] modifications public health messaging or medical health messaging.”

Ljung stated future research study ought to connect self-reported surveys with health information on the subject to get the very best of both worlds.

For this research study, the scientists examined information from 2,946,448 Swedish ladies ages 12 to 74 (typical age 44) from December 2020 to February 2022. Ladies who were pregnant, residing in assisted living home, or who had a history of menstrual or bleeding conditions, breast cancer or a kind of genital-related cancer, or who had a hysterectomy were left out from the research study.

The majority of ladies in the accomplice (87.6%) got a minimum of one vaccination, and 64% got 3 dosages by the end of the follow-up duration.

Covariates consisted of nation of birth, age, marital status, education, frequency of previous health care check outs, and if they were a health care employee.

More than 99% of menstrual-related sees were outpatient professional care visits.

Ljung and coworkers kept in mind that their dataset did not suggest whether a medical professional’s check out was prepared or severe, which is a constraint to the research study. They likewise explained that the time in between beginning of signs and in fact engaging with the health care system might be “significant, making the analysis of impact of various threat windows challenging.”

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    Rachael Robertson is an author on the MedPage Today business and investigative group, likewise covering OB/GYN news. Her print, information, and audio stories have actually appeared in Everyday Health, Gizmodo, the Bronx Times, and numerous podcasts. Follow


The research study was moneyed by the SciLifeLab National Covid-19 Research Program and the Knut and Alice Wallenberg Foundation, in addition to basic grants provided by the Swedish federal government, such as FORMAS (Research Council for Environment, Agricultural Sciences and Spatial Planning), a Swedish Research Council for Sustainable Development.

Ljung reported getting grants from Sanofi Aventis paid to his organization, and getting individual charges from Pfizer.

Co-authors reported relationships with AstraZeneca, Gilead, GSK/ViiV, MSD, Biogen, Novocure, Amgen, Novo Nordisk, Scandinavian Biopharma, Astellas Pharma, Janssen Biotech, Pfizer, Roche, Abbott Laboratories, Schering-Plough, UCB Nordic, and Sobi.

Dawson did not reveal any disputes of interest.

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Source Reference: Ljung R, et al “Association in between SARS-CoV-2 vaccination and health care contacts for menstrual disruption and bleeding in ladies prior to and after menopause: across the country, register based mate research study” BMJ 2023; DOI: 10.1136/ bmj-2023-074778.

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