At one point last summer, there were too many reports of protesters experiencing abnormal menstrual cycles after being exposed to tear gas for Britta Torgrimson-Ojerio, a nurse researcher at the Kaiser Permanente Center for Health Research in Portland, to dismiss them as coincidence.
A preschool teacher told Oregon Public Broadasting that if she inhaled a significant amount of gas at night, she would have her period the next morning. Other Portland residents shared stories periods that lasted for weeks and unusual spots. Transgender men described sudden spells that challenged hormones that had kept menstruation at bay for months or years.
Dr Torgrimson-Ojerio decided that she would try to determine if these anecdotes were outliers or representative of a more common phenomenon. She interviewed about 2,200 adults who said they were exposed to tear gas in Portland last summer. In a study published this week in the journal BMC Public Health, she reported that 899 of them – over 54% of potentially menstruating respondents – reported experiencing abnormal menstrual cycles.
“While we cannot say anything scientifically definitive about these chemical agents and a causal relationship to menstrual irregularities,” said Dr Torgrimson-Ojerio, “we can definitely state that in our study, most of the People who had menstrual cycles or a uterus reported menstrual irregularities after reporting exposure to tear gas. “
The downstream effects, like the impact on fertility, are not known, but “this is our call to action to ask our scientific community to look into this issue,” she said.
Dr Torgrimson-Ojerio also wondered if people had experienced other problems more than a few hours after being exposed to tear gas. She found that 80% of survey participants had it, with difficulty breathing being one of the most common complaints.
Kira Taylor, professor of epidemiology and population health at the School of Public Health and Information Sciences at the University of Louisville who is conducting a similar study, said the study by Dr. Torgrimson-Ojerio provided “some of the first strong evidence” that tear gas could be linked to menstrual abnormalities. It is also “the first study to document the long-term effects of tear gas exposure in a large population,” she said.
Sven-Eric Jordt, professor of anesthesiology, pharmacology and cancer biology at Duke University School of Medicine, who was not involved in the study, applauded the work.
Most of the research law enforcement and government rely on to educate them about tear gas safety “is outdated, often 50 to 70 years old, and falls short of modern toxicology approaches.” did he declare. “Most of these studies were carried out in young healthy men at the time, whether they were police or military, and not in women, or in a general civilian population representing protesters.”
Dr. Torgrimson-Ojerio and her colleagues recruited survey participants through social media and links on the Oregonian and Oregon Health Authority websites in July and August.
The researchers asked participants to explain precisely how their periods were affected after exposure to tear gas. Increased cramps, unusual spotting, and unusually heavy or long bleeding were the most common reactions. A number of people who usually don’t have a period due to hormone therapy or age have reported unexpected bleeding and bleeding, said Dr Torgrimson-Ojerio.
This study has limitations. It is not a random sample.
“It is possible that people who felt that their health was damaged by the tear gas were more likely to respond than people who were also exposed, but who did not experience such harmful effects,” said the Dr Taylor. “This means that some of the numbers may be exaggerated.”
Since subjects were allowed to participate anonymously, the researchers were unable to verify their accounts.
The study also cannot explain how or why tear gas might contribute to menstrual irregularities or to what extent other factors are also involved. The authors acknowledge that high levels of stress and anxiety among protesters, for example, could also have contributed to the physical reaction.
“It is possible that pain, stress, dehydration and exertion play a role,” said Dr Jordt. Alternatively, tear gas can act as an “endocrine disruptor,” interfering with normal hormonal function.
“CS tear gas, sometimes used by police, is a chlorinated chemical compound and produces additional chlorine byproducts when burned in cans used by police,” he said. “Exposure to chlorinated chemicals can affect menstrual health.”
Alexander Samuel, a molecular biologist in France, has been investigating similar issues since French protesters began reporting menstrual irregularities.
He mentioned two more areas to explore: whether tear gas is metabolized to cyanide, which can cause heavy menstrual bleeding, and the role that a traumatic event can play in altering menstrual cycles.
Suspicions of tear gas and menstruation first surfaced more than a decade ago during the Arab Spring protests, noted Dr Jordt.
In 2011, Chile also banned the use of tear gas after a study suggested CS gas could cause miscarriages and harm young children. Three days later, Chilean police lifted the ban, insisting the type of tear gas used was perfectly safe.