Association of Ambient Air Pollution and Pregnancy Outcomes Among Women with Assisted Reproductive Technology in Qingdao, China: A Retrospective Cohort Study.

BACKGROUND

Ambient air pollutants, a major global public health concern, have been widely documented in recent years as key risk factors for adverse reproductive system outcomes. Assisted reproductive technology (ART) has become an important therapeutic means for infertility, but its pregnancy outcomes are influenced by various environmental factors. Thus, we explored the effects of ambient air pollutants on populations undergoing ART.

METHODS

The retrospective cohort study included 3478 infertility patients with fresh embryo transplantation residing in Qingdao City who underwent in vitro fertilization and intracytoplasmic sperm injection in China from 2021 to 2023. We employed multivariable logistic regression to assess the effects of contaminants on oocyte quality, embryonic development, and pregnancy outcomes. Stratified analysis was conducted to identify potential vulnerable subpopulations.

RESULTS

Regression showed that NO2 exposure showed negative association with biochemical pregnancy rates (aOR=0.967, 95% CI=0.935-0.999) and clinical pregnancy rates (aOR=1.044, 95% CI=1.001-1.088). CO exposure was positively correlated with cleavage rate (aOR=1.293, 95% CI=1.048-1.594) and day 3 high-quality embryo rate (aOR=1.462, 95% CI=1.054-2.028). PM2.5 and NO2 exposure were negatively associated with the number of oocyte retrieval and MII oocytes. WQS index was negatively correlated with MII oocyte count (aOR=0.916, 95% CI=0.857-0.978). BKMR analysis confirmed PM2.5 correlated negatively with MII oocyte count. Stratified analyses revealed women aged ≥35 were more sensitive to NO2, while those <35 were to O3. Women with ≥7 oocytes were more sensitive to PM2.5 and NO2.

CONCLUSION

Ambient air pollutants exert significant negative effects on ART-related reproductive outcomes. Women aged ≥35 were more sensitive to NO2, whereas those <35 were O3. Women with ≥7 oocytes were more sensitive to PM2.5 and NO2. This study provides a scientific basis for the prevention of air pollution and clinical decision-making in ART population. It is necessary to develop personalized intervention strategies for sensitive populations and strengthen the environmental control of related pollutants.