A new study funded by the U.S. National Institutes of Health's Office of Research on Women's Health found a link between COVID vaccines and lengthened women's menstrual cycles. The study was led by Dr. Allison Edelman of the Oregon Health & Science University in Portland, who found that COVID vaccines impact a woman's menstrual cycle.

The new study was published in the January edition of the journal Obstetrics & Gynecology. Researchers analyzed a total of 3,959 individuals, 2,403 of which were vaccinated with either a Pfizer or Moderna COVID vaccine and 1,556 people who were not vaccinated.

According to the summary of the study, "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."

Researchers then found that on average, the first dose of the COVID vaccine was linked to a 0.71-day cycle increase in cycle length. Consecutively, the second dose was associated with a 0.91-day increase in cycle length. National Institutes of Health (NIH) Eunice Kennedy Shriver National Institute of Child Health and Human Development director Dr. Diana W. Bianchi underscored how "little research has previously been conducted on how vaccines for COVID-19 or vaccines for other diseases could potentially influence the menstrual cycle."

Dr. Bianchi added, however, that it was "reassuring that the study found only a small, temporary menstrual change in women." She also said that the study was "an opportunity to counsel women about what to expect from COVID-19 vaccination so they can plan accordingly."

Meanwhile, a U.K. menstrual expert said that small changes to menstrual cycles are often observed by women following COVID vaccine inoculation, the Economic Times reported. Imperial College London's Victoria Male observed studies from the US and Norway that tracked women's menstrual cycles as "reassuring."

According to the report, a study of more than 5,600 individuals in Norway showed how much periods may actually vary naturally. About 40% saw at least one change following COVID vaccination, with the most common observation being heavier than normal bleeding. Moreover, the Medicines and Healthcare products Regulatory Agency said it received over 37,000 reports of "unexpected vaginal bleeding, heavier and delayed periods after a COVID-19 jab."

The National Post reported that the study was part of the $1.67 million grant to discover the ways that COVID vaccines affect menstrual changes. This comes after several lobbying efforts from pharmaceutical companies such as Pfizer and Moderna, which have "reaching record highs in terms of spending and personnel hired," as per the report.

It added that such "massive lobbying campaigns" were "likely responsible for nationwide vaccine mandates" which has been repeatedly shut down by the Supreme Court.

Earlier this month, the Supreme Court ruled that the Occupational Safety and Health Administration (OSHA) exceeded its authority in carrying out the Biden administration's COVID vaccine mandate for private businesses with at least 100 employees, which required them to get vaccinated or face weekly testing, while the unvaccinated would need to wear face masks indoors at work.