A U.S. National Institutes of Health study found that COVID-19 vaccines lengthened women’s menstrual cycles.
The study, published in a January edition of Obstetrics & Gynecology, compared menstrual cycle lengths between women vaccinated and unvaccinated against COVID-19.
“For vaccinated individuals, data was from three consecutive cycles before vaccination and from three more consecutive cycles, including the cycle or cycles in which vaccination took place. For unvaccinated individuals, data was collected for six consecutive cycles,” reads a summary of the study.
Of the 3,959 individuals analyzed, 2,403 were vaccinated, with most receiving either a Pfizer or Moderna jab, and 1,556 were unvaccinated.
On average, the first vaccination dose was associated with a .71-day cycle increase in cycle length and the second dose with a .91-day increase.
Dr. Diana W. Bianchi, Director of the National Institutes of Health (NIH) Eunice Kennedy Shriver National Institute of Child Health and Human Development, emphasized how “little research has previously been conducted on how vaccines for COVID-19 or vaccines for other diseases could potentially influence the menstrual cycle.”
The vaccine side effect follows lobbying efforts from pharmaceutical giants – especially Pfizer and Moderna – reaching record highs in terms of spending and personnel hired. The massive lobbying campaigns are likely responsible for nationwide vaccine mandates, which have subsequently been struck down by district courts.
At the time of publication, Reuters has not covered the NIH study.