Environment/Climate Change
Examining early gestational susceptibility to ambient air pollutants and risk of pregnancy loss in a time-to-pregnancy cohort Kaniz Rabeya* Kaniz Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya Rabeya University of Massachusetts Amherst
Background: Early pregnancy is a highly sensitive developmental period in relation to pregnancy loss. We examined air pollution exposure during the earliest gestational weeks encompassing implantation, placentation, and embryogenesis.
Methods: A preconception time-to-pregnancy study (EAGeR trial, 2007-2011) enrolled 1,001 women (18-40 years) from the Intermountain West, with most residing along the Wasatch Front. Residential air pollution exposure was estimated from Air Quality Data for Health-Related Applications (AQDH) & Community Multiscale Air Quality (CMAQ) Models, including ozone (O3), fine particulate matter (PM2.5), & nitrogen dioxide (NO2) and averaged across gestational weeks encompassing pre-ovulation & early embryo development (weeks 1-3), implantation & early loss (4&5), & clinical pregnancy loss (6-9). Pregnancy loss was defined as an observed loss after detection of pregnancy using human chorionic gonadotropin. Generalized linear models estimated relative risk for pregnancy loss per interquartile range increase in pollutants, adjusting for age, income, education, race/ethnicity, and season.
Result: A trend of increasing risk of pregnancy loss was observed during the earliest gestational weeks, including pre-ovulation & early embryo development for both models, although estimates were imprecise. In gestational week 4, PM2.5 was associated with a 29% higher risk of pregnancy loss (RR 1.29, 95% CI 1.00, 1.66 per 2.4 µg/m³ for CMAQ model) while O3 showed no clear association and NO2 was associated with a non-significant risk decrease. Conversely, during weeks encompassing clinical pregnancy loss, NO2 was associated with an imprecise trend of higher pregnancy loss (RRs ranging from 1.20 to 1.45), while PM2.5 RRs ranged from 0.65 to 0.92.
Conclusion: Exposure to air pollution early in pregnancy may be associated with pregnancy loss, although interdependencies among pollutants may limit inferences. Next steps include evaluating broader air pollution mixtures.