Recently, Professor Sun Yun's team from the Department of Reproductive Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, published the latest research results in The International Authoritative Journal of Environmental Health (Environment International, impact factor of 11.694), and found that air pollutant exposure significantly reduced the live birth rate of IVF fertile women. The results suggest that IVF couples should take individualized protection measures as soon as possible to improve the air quality of the living environment and reduce avoidable dust and exhaust gas exposure.
In recent years, epidemiological studies and basic research results have shown that air pollutant exposure can affect various reproductive stages including the female menstrual cycle, ovarian reserve, male spermatogenesis and early embryonic development, and its potential mechanisms include causing oxidative stress, inflammation, metabolomics changes, epigenetic modifications, etc. With the adjustment of the mainland population strategy and the implementation of the three-child policy, the demand for assisted reproductive and fertility technology has surged. More data show that in the past 10 years, the proportion of the mainland population born with assisted reproductive technology has increased by 4 times, from 0.46% in 2009 to 2.37% in 2018. The importance of assisted reproductive technology for fertility has become increasingly prominent, and the impact of air pollutants on the fertility of assisted reproductive fertility women has attracted more and more attention.
In this retrospective study, Professor Sun Yun's team used the location advantage of the Fertility Center of Renji Hospital to study 12,665 couples from the Yangtze River Delta region who underwent IVF or ICSI fertility at the center from 2015 to 2019, including 4,085 fresh embryo transfer cycles and 8,580 frozen embryo transfer cycles. The time and space exposure values of individuals were obtained using data from 149 air quality state-controlled sites in the Yangtze River Delta region and the specific addresses of the couples included in the study.
Unlike previous studies that limited the length of exposure windows to 3 months of egg renewal in women, this study extended the exposure window to 1 year before egg retrieval for analysis. The findings suggest that increased exposure to major air pollutants (PM10, PM2.5, SO2 and CO) in IVF fertile women in the year prior to egg retrieval will significantly reduce the rate of live births after embryo transfer, and this adverse effect is more pronounced in women undergoing frozen embryo transfer.
This study provides a factual reference for the relationship between air pollutant levels and IVF fertility outcomes in the Yangtze River Delta region, suggesting that couples who are willing to undergo IVF fertility should carry out corresponding individualized protection measures as soon as possible, and can improve IVF fertility outcomes by improving the local air quality level in the living environment, reasonable outdoor protection, and reducing avoidable dust and exhaust gas exposure.
Dr. Zhang Chuyue, Dr. Yao Ning and Dr. Lu Yao of the Department of Reproductive Medicine of Renji Hospital are the co-first authors of the paper, and Professor Sun Yun of the Department of Reproductive Medicine of Renji Hospital is the corresponding author. Dr. Ji Zhou, Department of Air and Ocean Sciences and Institute of Air Sciences, Fudan University, provided strong support for this research. The research has been funded by the National Key R&D Program, the National Natural Science Foundation of China, the Shanghai Leading Talents Program, the SHDC Clinical Research Program and many other topics.