Two chemicals commonly found in household detergents - ADBAC and DDAC - were found to cause reproductive decline in mice.
This is not the first time commonly used chemicals have been found to interfere with reproduction. Last year, Medical News Today reported on a study by researchers from Brigham and Women's Hospital in Boston, MA, suggesting bisphenol A (BPA) - a chemical used to make plastics and other resins - may cause infertility in women.
In this latest study, led by Dr. Terry Hrubec of the Virginia-Maryland College of Veterinary Medicine, researchers found that two chemicals - alkyl dimethyl benzalkonium chloride (ADBAC) and didecyl dimethylammonium chloride (DDAC) - had a similar effect in mice.
These chemicals are present in an abundance of products that we come into contact with every day, such as household cleaners, disinfectants, hand sanitizers, fabric softeners and even preservatives in cosmetics. But the effect they have on humans is a mystery.
"It is likely that you have these chemicals in your house," says Dr. Hrubec. "The answer to the question, 'Are these chemicals harmful to humans?' is that we simply don't know."
ADBAC and DDAC caused reproductive decline in mice
According to Dr. Hrubec, ADBAC and DDAC have never been subject to rigorous safety or toxicity testing, as research investigating these chemicals took place in the 1950s and 1960s before toxicity studies were standardized.
"In the 1980s, toxicity researchers developed and implemented Good Laboratory Practices, or GLPs," explains Dr. Hrubec. "These are guidelines and rules for conducting research so that it is reproducible and reliable. All of the research on these chemicals happened before that."
But an observation in her laboratory led her to believe these compounds should be subject to more vigorous testing.
After seeing reproductive decline in her mice, she noticed that her laboratory staff were washing their hands with a disinfectant that contained ADBAC and DDAC prior to touching them. This observation led her to a study conducted by Patricia Hunt, of Washington State University, which reported the same finding.
Dr. Hrubec and Hunt, along with colleagues from Washington State and Virginia-Maryland College of Veterinary Medicine, decided to investigate the association further.
They found that when female mice were exposed to ADBAC and DDAC - which belong to a class of chemicals called quaternary ammonium compounds - they took much longer to become pregnant, and when they did conceive, they gave birth to fewer babies. Furthermore, 40% of female mice exposed to these chemicals died in late pregnancy or during delivery.
Dr. Hrubec notes that although these chemicals appear to be toxic to mice, it cannot yet be said if they would have the same effect in humans.
But given the widespread use of these compounds in products that we are frequently exposed to, she believes further research into their potential implications for human reproduction is warranted.
Dr. Hrubec adds:
"If these chemicals are toxic to humans, they could also be contributing to the decline in human fertility seen in recent decades, as well as the increased need for assistive reproductive technologies such as in vitro fertilization (IVF)."
She suggests that an epidemiological study could help find out whether women highly exposed to ADBAC and DDAC - such as health care workers - have more difficulty becoming pregnant.
Earlier this year, Medical News Today reported on a study suggesting that chemicals found in toothpaste and sunscreen may interfere with sperm function, potentially affecting fertilization.