Nature article: COVID vaccines linked to unexpected vaginal bleeding

Women who don’t menstruate — including postmenopausal women and those on contraceptives — were several times more likely to experience unexpected vaginal bleeding after COVID-19 vaccination than before the vaccines were offered, a study1 finds.

When COVID-19 jabs were rolled out globally, many women reported heavier-than-usual menstrual bleeding soon after vaccination. Study author Kristine Blix, at the Norwegian Institute of Public Health in Oslo, wanted to look at the trend systematically, particularly in women who don’t normally have periods, such as those taking contraceptives or who have been through menopause. The work is published in Science Advances.

The team didn’t investigate the reasons for the unexplained bleeding, but suggested that it could be linked to the SARS-CoV-2 spike protein used in the vaccines. In general, the COVID-19 vaccines have been found to be safe and effective.

https://www.nature.com/articles/d41586-023-02996-6

 

Unexpected vaginal bleeding and COVID-19 vaccination in nonmenstruating women
Kristine Blix; Ida Laake; Lene Juvet; Anna Hayman Robertson; Ida Henriette Caspersen; Siri Mjaaland; Siri N. Skodvin; Per Magnus; Berit Feiring; Lill Trogstad

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.

Link | PDF (Science Advances)

 

See also Investigating trends in those who experience menstrual bleeding changes after SARS-CoV-2 vaccination (2022, Science Advances)

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