Minnesota study links tear gas exposure with menstrual disruptions

About 83% of people in a survey by Minnesota researchers reported reproductive health problems such as cramps and early periods after exposure to tear gas or other chemical irritants.

Limitations of the study prevented the researchers from declaring a cause and effect, but they said the results are a first step and should give law enforcement leaders pause over their use of these irritants for crowd control.

"The study is only the beginning of raising questions of the health outcomes related to tear gas exposure," said Asha Hassan, a researcher with Planned Parenthood North Central States and the University of Minnesota's Center for Antiracism Research for Health Equity.

Planned Parenthood supported the study, because people had anecdotally reported disrupted menstrual cycles after exposure to tear gas that was used to disperse rioters and protesters following the police killing of George Floyd in Minneapolis. The study design also was approved by a U institutional review board.

The survey results, revealed Monday, showed that more than two-thirds of respondents nationwide reported cramps after tear gas exposure in 2020 or 2021 and more than half reported early menstrual bleeding. Breast tenderness and delayed menstrual bleeding were other common concerns.

"When a period comes early or late It has significant impact on a person's life. Many times it feels like a lack of control," said Dr. Sarah Traxler, chief medical officer for the local Planned Parenthood chapter. She also coauthored the study that was published in Frontiers in Epidemiology, a medical journal.

These disruptions can be particularly problematic for women planning a pregnancy or struggling with fertility, and for trans and nonbinary people, she added.

Researchers used social media ads and Planned Parenthood email groups to recruit participants, and included more than 1,200 responses in their study. Participants could self-report gender but had to have a uterus to be included.

More than 90% of participants took hormones for birth control or other purposes, which was one limitation. Researchers couldn't determine whether tear gas exposure would produce health problems in the absence of these medications.

Reproductive health issues after tear gas exposure also were more likely in respondents who said they had histories of stress or trauma disrupting their menstrual cycles. So its possible that the stress of protests and police confrontations affected them as much as the chemical irritants.

However, the researchers still found a relationship between tear gas exposure and reproductive health issues when factoring out this menstrual stress response. They also found that multiple exposures to tear gas increased the likelihood of health effects.