Effect of air pollutants on the processes of fertilization and embryo formation

Abstract

Abstract Fertilization and embryo cultures are at risk of direct exposure of germ cells to air pollutants in assisted reproductive technology. The degree of exposure of germ cells to the pollutants is different in vitro fertilization methods, conventional in vitro fertilization (c-IVF), and intracytoplasmic sperm injection (ICSI) cycles. However, there are conflicting conclusions about the effect of air pollutants on in vitro cultures. A retrospective analysis of fertilization and embryo cultures of 2689 c-IVF and 1133 ICSI cycles that underwent assisted reproductive treatment for the first time was performed. Weighted binary logistic regression models were used to investigate the correlation between air pollutant exposure and fertilization, cleavage, and embryo development. We found that D− 1-NO2 (adjusted odds ratios (aOR): 0.996; 95% CI: 0.992–1.000) was negatively correlated with normal fertilization, whereas D− 1-PM2.5 (aOR: 0.989; 95% CI: 0.982–0.995) and D1-O3 (aOR: 0.998; 95% CI: 0.997–1.000) were negatively correlated with high-quality embryo formation, D− 1-CO (aOR: 1.631; 95% CI: 1.152–2.311) and D− 1-O3 (aOR: 1.002; 95% CI: 1.001–1.004) were positively correlated with high-quality embryo formation. In c-IVF cycles, D0-SO2 (aOR: 0.974; 95% CI: 0.953–0.995) was negatively correlated with normal fertilization, D− 1-PM2.5 (aOR: 0.986; 95% CI: 0.978–0.993) was negatively correlated with high-quality embryos formation, and D− 1-CO (aOR: 1.498; 95% CI: 1.002–2.240; p = 0.049) was positively correlated with high-quality embryos formation. In ICSI cycles, D− 1-NO2 (aOR: 0.991; 95%CI: 0.983–0.999) was negatively correlated with normal fertilization, whereas D− 1-CO (OR: 2.161; 95%CI: 1.068–4.373) and D− 1-O3 (OR: 1.004; 95%CI: 1.001–1.007) were positively correlated with high-quality embryos formation. We conclude that air pollutants affect the processes of fertilization and embryo development in vitro; however, the types and interference stages of air pollutants that affect germ cell cultures in vitro are different in c-IVF and ICSI.