I'm guessing you mean the study being conducted by Kathryn Clancy an associate professor at the University of Illinois and Katherine Lee a postdoctoral research scholar at Washington University School of Medicine?... There is a proper investigation taking place two doctors in American have launched an investigation into it after experiencing it themselves ,it's on all the US news sites as was the case with Israel .
It's covered in this newspaper article ...
Are period changes a vaccine side effect? 2 researchers are tracking it.
Two researchers are trying to catalog people’s menstrual experiences after receiving the COVID-19 vaccine.
www.chicagotribune.com
A few quotes from the people undertaking the study which may be worth highlighting:
“I ended up finding a lot of people with similar experiences,” Clancy said. “But also, to be fair, a lot of people who were like, ‘Really, I noticed nothing,’ and some people who said, ‘Actually I had the opposite, where I’ve had a later or lighter period.’”
“Our survey cannot tell us anything about prevalence or the number of people who are affected,” Lee said. “What we can do is look for associations and trends that help us direct whatever the next study would be.”
Also a couple more doctors quoted in the article:
Dr. Rakhi Shah, an OB-GYN at Northwestern Medicine Delnor Hospital, said she doesn’t see a way the COVID-19 vaccines could affect menstruation. “I think that there’s really no biological mechanism that is plausible in terms of how that could be possible,” Shah said. “I think that potentially people are having normal menstrual pain plus the aches and pains that are associated post-vaccine, and maybe combining all of that together and associating it.”
Dr. Julie Levitt, an OB-GYN at Northwestern Medicine said two patients have come to her with concerns specifically related to their periods after getting vaccinated. “Bleeding occurs for so many reasons that it’s really hard to isolate the two,” Levitt said.
She also said the COVID-19 vaccine could be creating a hormonal spike that could trigger bleeding. “A hormone rises, it goes down, you bleed a withdrawal bleed. But is that a bad thing? No,” Levitt said. Levitt emphasized that this was not a subject of concern, nor a reason to stop taking birth control. “No. 1, I wouldn’t worry. No. 2, contact your doctor if you want to talk about it to gain that reassurance,” Levitt said. “If it does continue after a few weeks following the administration of the vaccine, it probably is something else.”