Does exposure to air pollution during different time windows affect pregnancy outcomes of in vitro fertilization treatment? A systematic review and meta-analysis

Air pollution and fecundability in a North American preconception cohort study

“…Ecologic studies in the U.S. ( Xue and Zhu, 2018b ), Spain ( Nieuwenhuijsen et al, 2014 ), and China ( Xue and Zhu, 2018a ) have found that counties or census tracts with higher levels of air pollution have lower fertility rates. Associations between air pollution and markers of fertility have also been reported in studies of couples undergoing in vitro fertilization (IVF) ( Boulet et al, 2019 ; Choe et al, 2018 ; Dai et al, 2021 ; Gaskins et al, 2018 , 2019 ; Iodice et al, 2021 ; Jin et al, 2022 ; Legro et al, 2010 ; Li et al, 2020 ; Liu et al, 2022 , 2023 ; Qiu et al, 2019 ; Shi et al, 2021 ; Tartaglia et al, 2022 ; Wu et al, 2021 , 2023 ; Zeng et al, 2020 ; Zhang et al, 2022 ; Quraishi et al, 2019 ) and among couples trying to conceive spontaneously ( Li et al, 2021 ; Mahalingaiah et al, 2016 ; Mendola et al, 2017 ; Nobles et al, 2018 ; Slama et al, 2013 ; Wesselink et al, 2020 , 2022 ). However, the pollutants associated with reduced fertility and the window of exposure during which an association was observed were not consistent across studies.…”

“…However, the pollutants associated with reduced fertility and the window of exposure during which an association was observed were not consistent across studies. For example, long-term PM 2.5 concentrations have generally not been strongly associated with reduced fertility ( Mahalingaiah et al, 2016 ; Wesselink et al, 2022 ; Quraishi et al, 2019 ) (with the exception of a retrospective cohort in China) ( Li et al, 2021 ), whereas PM 2.5 concentrations across the menstrual cycle and during specific critical windows of IVF ( e.g ., between oocyte retrieval and embryo transfer) were associated with reduced fertility in some ( Gaskins et al, 2019 ; Slama et al, 2013 ; Wesselink et al, 2022 ), but not all ( Legro et al, 2010 ; Nobles et al, 2018 ) studies ( Liu et al, 2023 ). Similar inconsistencies in the relevant timing of exposure exist for studies examining NO 2 ( Choe et al, 2018 ; Gaskins et al, 2019 ; Legro et al, 2010 ; Nobles et al, 2018 ; Wesselink et al, 2022 ; Quraishi et al, 2019 ) and O 3 ( Choe et al, 2018 ; Gaskins et al, 2019 ; Legro et al, 2010 ; Nobles et al, 2018 ; Wesselink et al, 2022 ).…”

Does Exposure to Ambient Air Pollution Affect Gestational Age and Newborn Weight?—A Systematic Review

“…Other studies show a more significant influence in the first trimester, which is vital for organogenesis [ 26 , 34 , 40 , 57 , 63 , 64 , 72 , 76 ]. Nevertheless, it is believed that the influence in the first trimester has a binary effect on the pregnancy, either leading to a miscarriage or not leaving the pregnancy unaffected by any adverse consequences during pregnancy [ 26 ], as was shown by Bai et al and Liu et al in their meta-analyses assessing pregnancy outcomes including miscarriage [ 112 , 113 ]. The influence in the second and third trimesters may better reflect the influence of air pollutants on SGA as organogenesis is almost complete, and the fetus mainly grows during this period [ 25 , 31 , 33 , 37 , 43 , 49 , 59 , 64 , 72 , 76 , 81 , 87 , 88 ].…”

Individual-level air pollutants exposure and pregnancy outcomes in patients who underwent assisted reproductive technology: A retrospective longitudinal cohort study

“…Despite that some publications have linked air pollution with high risks of adverse pregnancy outcomes, 20,21 evidence on such impacts in ART patients is limited and mixed. 22,23 Some reported adverse effects on IVF outcomes, [24][25][26][27] whereas others observed non-significant or opposing results. [28][29][30][31] For example, Wu and colleagues detected that air pollution [O3, nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO)] was adversely associated with pregnancy and live birth in patients receiving IVF treatment.…”

“…Liu and colleagues designed seven different time windows to explore the correlation of air pollution and IVF outcomes, while the longest window only explored up to 85 days before oocyte retrieval. 23 Less research, meanwhile, has considered the role of frozen embryo transfer (FET) cycles in associations of air pollution with pregnancy outcomes. Presently, if it occurs a failed fresh transfer or freeze-all cycle, according to the acknowledged standard clinical practice, FET cycles treatment will be performed again after one menstrual cycle at least.…”