Factors affecting menstrual cycle changes following COVID-19 vaccination in Korean women of reproductive age: an exploratory correlational study.
Sunhee Lee, Kyung-Eui Bae, Hyun-Jung Park
PMID 41531407WHAT IT FOUND
111 of 227 vaccinated Korean women reported menstrual abnormality after vaccination; irregular cycles, heavy bleeding, age, body mass index, marital status and prior infection were associated.
Nurses can use this for counselling, not proof vaccine caused changes.
Key findings
01111 of 227 Korean women reported menstrual abnormality after COVID-19 vaccination.
02In adjusted analysis, irregular menstrual cycles had an odds ratio of 17.26 for post-vaccination menstrual change.
03Adjusted analysis also associated menstrual change with age, body mass index, marital status, prior infection status, dose count, heavy bleeding and intermittent bleeding.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
Cross-sectional design cannot show vaccination caused the changes. Self-report and online convenience sampling may overestimate or miss changes. Only women with prior regular cycles were included, and gynecologic, thyroid and chronic disease were excluded, so findings do not apply to all women. No objective bleeding, hormone or cycle-tracking data were collected. Stress, sleep, medications and infection timing or severity were not measured.
Declared interests
The authors declared no conflicts of interest and reported no funding.
The easy way to misread this
Do not conclude that COVID-19 vaccination caused menstrual cycle changes. The study measured associations using self-report, so timing and cause cannot be separated.