P–183 Air quality oscillations inside the IVF laboratory do not affect clinical outcomes
Authors: Mass. Hernaez J , Montalvo V , Garcia-Faura A , Marques B , López-Teijón M 
Published: August 2021

Abstract

Study question
Do air contaminant oscillations impair in vitro fertilization clinical results?

Summary answer
Oscillations of the main air contaminants (SO2, NO, NO2, O3, CO, PM10, C6H6) inside the IVF laboratory do not impair success rates.

What is known already
Pollution is a challenge that as humans we face around the world. Given the limited number of studies that demonstrate the effect of pollution into IVF treatments, the effect that air contaminants have on in vitro human gametes/embryos is not clear.
IVF laboratories are designed to limit the stress that gametes and embryos suffer during culture and manipulation. Controlling temperature, humidity, light, and filtering the air is essential to have a successful IVF program. However, HEPA and active carbon filters are not enough to ensure that gametes/embryos are not exposed to contaminants, exposing them to potentially harmful gases and particles.

Study design, size, duration
Prospective study comprising treatments throughout 2019, recording levels of the main air contaminants (SO2, NO, NO2, O3, CO, PM10, C6H6) every 10 minutes inside the IVF laboratory in order to assess the effect of these pollutants. We included egg donor cycles without PGT-A.

Participants/materials, setting, methods
A total of 724 egg donation treatments were included. Using uninterrupted culture (Global, CooperSurgical) in time lapse incubators (Embryoscope, Vitrolife). A mean concentration of every pollutant during the 6 days of every treatment was calculated. We analyzed success rates such as fertilization rates, blastocyst rates, pregnancy rates, implantation rates, miscarriage rates, and live birth rates.

Main results and the role of chance
Our results show that no contaminant affects neither fertilization rates nor good quality blastocyst rates.
The only pollutants that have an association with pregnancy rates are NO and CO (p = 0.014 y p = 0.021) in both the univariate and the multivariate statistical analysis. Still, this association is week and could be explained due to the large data set. When analyzing further data we do not find any association between the dose of contaminants and implantation rates, miscarriage rates nor live birth rates (p &gt; 0.01) demonstrating that oscillations in levels of these contaminants do not affect clinical results.
Our results differ with the results from a previous study where they detected an effect of SO2 and O3 when analyzing frozen embryo transfer results. This might be explained because the levels of these gases were lower in our clinic and the pregnancy and live birth rates are higher.

Limitations, reasons for caution
Although we measured the levels of the contaminants inside the IVF laboratory, we did not measure the levels inside the incubators.
Wider implications of the findings: This results show that IVF success rates are not impaired by oscillations in air quality if the laboratory does use the necessary HEPA and active-carbon air filter systems.

Trial registration number
Not applicable