In the first comprehensive review article of its kind, a Mayo Clinic fertility consultant describes how evidence for the importance of air quality in clinical embryology laboratories—in particular, the role of volatile organic compounds (VOCs)—has resulted in an evolution of clinical practice that has contributed to improved outcomes. Even so, evidence of best practices is lacking, and there have been no controlled studies on air quality, according to the author Dean Morbeck, Ph.D., a consultant in the Division of Reproductive Endocrinology and Infertility at Mayo Clinic.
“This correlation between air quality and outcome is known in practice, but it hasn’t been well studied,” says Dr. Morbeck. “For most people, the importance of VOC filtration is intuitively obvious, but there’s little data to support the importance of good air filtration.”
According to Dr. Morbeck’s review, published in the Journal of Assisted Reproduction and Genetics, the idea of filtering VOCs remains controversial within this young industry.
“There are two different ‘camps’out there,” says Dr. Morbeck. “Some laboratories only focus on reducing particle counts, using high efficiency particulate air filters, which in theory makes for a safe culture environment by minimizing the risk of microbial contamination. In contrast, other labs still filter out particles but emphasize VOC filtration, using solid-phase filtration or photocatalytic oxidation. Recent evidence shows that VOCs likely cause the most damage and that appropriate VOC filtration for an individual clinic is very important. Yet, there are still people who don’t believe in chemical filtration. They’re asking, ‘Where’s the evidence’"
The best piece of evidence to date is reflected in a paper from the University of Iowa (which prompted Dr. Morbeck’s review). The study focuses on an embryology laboratory that went six months without carbon filtration—the filters had been inadvertently removed. The result was six months of reduced in vitro fertilization (IVF) outcomes. “While it took the clinic several months to identify the problem,” says Dr. Morbeck, “they eventually determined it was the carbon filters. Even though they had good particle filtration, they didn’t have any chemical air filtration, and outcomes were adversely affected.”
Currently, recommendations that are based on industrial clean-room particulate standards pay little attention to chemical air filtration. In fact, the American Society for Reproductive Medicine, in its published guidelines, doesn’t even mention VOC filtration for labs.
“In Europe, they have guidance for particulate filtration per clean-roomstandards but nothing for VOCs,” says Dr. Morbeck. “Brazil is the only country I know of that includes VOCs in its guidelines as something important to control. In the U.S., we have zero guidance or regulations.”
“The need for air filtration is likely clinic-dependent,” says Dr. Morbeck. “There might be some clinics that are totally isolated from outdoor air pollution, for example. And if they have good recirculation of clean outdoor air and limited indoor VOC generation, they probably don’t need much chemical filtration—in which case, VOC filtration systems that are being sold now may be an unnecessary expense.”
Many clinics are embracing specialized air-quality equipment—without truly knowing how much filtration they need, or don’t need—because their embryology laboratories have evolved into epicenters of assisted reproductive technology. The practice of IVF has moved to blastocyst transfers and utilization of trophectoderm biopsy for preimplantation genetic testing. Thus, a laboratory’s ability to culture, biopsy, and freeze blastocysts is a rate-limiting step that depends on technical proficiency and a supportive and stable culture environment based on a foundation of high-quality ambient air.
Dr. Morbeck does see some change coming. Papers, like the one from the University of Iowa, are beginning to emerge about the impact of chemical filtration. “Hopefully, we can start developing standards based on this new evidence,” he says. “The whole point of the review is to recognize this evidence that supports VOC filtration in order to bring attention to a gap in our current industry standards.”