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

Lill Trogstad; Ida Laake; Anna H Robertson; Siri Mjaaland; Ida H Caspersen; Lene K Juvet; Per Magnus; Kristine Blix; Berit Feiring

doi:10.1016/j.vaccine.2023.06.088

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

Vaccine. 2023 Aug 14;41(36):5271-5282. doi: 10.1016/j.vaccine.2023.06.088. Epub 2023 Jul 3.

Authors

Lill Trogstad¹, Ida Laake², Anna H Robertson¹, Siri Mjaaland¹, Ida H Caspersen³, Lene K Juvet¹, Per Magnus³, Kristine Blix¹, Berit Feiring¹

Affiliations

¹ Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway.
² Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway. Electronic address: ida.laake@fhi.no.
³ Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway.

PMID: 37451876
DOI: 10.1016/j.vaccine.2023.06.088

Abstract

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.

Keywords: Adverse effects of vaccination; COVID-19 vaccine; Cohort study; Menstrual disturbances.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19 Vaccines* / adverse effects
COVID-19* / epidemiology
COVID-19* / prevention & control
Female
Hemorrhage
Hormones
Humans
Menstruation Disturbances* / chemically induced
Menstruation Disturbances* / epidemiology
Vaccination / adverse effects
Young Adult

Substances

COVID-19 Vaccines
Hormones