Ambient Air Pollution Exposure and Fecundability in Women Undergoing In Vitro Fertilization

Abstract

Background: Limited research suggests ambient air pollution impairs fecundity but groups most susceptible have not been identified. We studied whether long-term ambient air pollution exposure before an in vitro fertilization (IVF) cycle was associated with successful livebirth, and whether associations were modified by underlying infertility diagnosis. Methods: Data on women initiating their first autologous IVF cycle in 2012–2013 were obtained from four US clinics. Outcomes included pregnancy, pregnancy loss, and livebirth. Annual average exposure to fine particulate matter (PM2.5), PM10, and nitrogen dioxide (NO2) before IVF start were estimated at residential address using a validated national spatial model incorporating land-use regression and universal kriging. We also assessed residential distance to major roadway. We calculated risk ratios (RR) using modified Poisson regression and evaluated effect modification (EM) by infertility diagnosis on additive and multiplicative scales. Results: Among 7,463 eligible participants, 36% had a livebirth. There was a nonsignificant indication of an association between PM2.5 or NO2 and decreased livebirth and increased pregnancy loss. Near-roadway residence was associated with decreased livebirth (RR = 0.96, 95% CI = 0.82, 0.99). There was evidence for EM between high exposure to air pollutants and a diagnosis of diminished ovarian reserve (DOR) or male infertility and decreased livebirth. Conclusions: Despite suggestive but uncertain findings for the overall effect of air pollution on fecundity, we found a suggestive indication that there may be synergistic effects of air pollution and DOR or male infertility diagnosis on livebirth. This suggests two possible targets for future research and intervention.

Air pollution and fecundability: Results from a Danish preconception cohort study

“…We assessed both long‐ and short‐term exposures to try to identify the aetiologically relevant window of exposure. Because we did not have sufficiently granular data on the numerous biological processes that occur leading up to pregnancy (i.e., folliculogenesis, ovulation, implantation), we were unable to measure exposure in finer windows that may be more biologically relevant, as studies of couples undergoing IVF have done 29–32 . In addition, because the vast majority of couples reside at the same address and exposure was residence‐based, we were not able to separate out effects of air pollution on female versus male partners.…”

“…Because we did not have sufficiently granular data on the numerous biological processes that occur leading up to pregnancy (i.e., folliculogenesis, ovulation, implantation), we were unable to measure exposure in finer windows that may be more biologically relevant, as studies of couples undergoing IVF have done. [29][30][31][32] In addition, because the We measured time-to-pregnancy using self-reported information on LMP dates, menstrual cycle length, attempt time at study entry, and pregnancy status during follow-up. These variables were measured retrospectively on bi-monthly follow-up questionnaires, rather than prospectively using daily diaries.…”

The impact of fine particulate matter (PM) on various beneficial functions of human endometrial stem cells through its key regulator SERPINB2

“…Similarly, women exposed to high concentrations of PM during the follicular phase of the menstrual cycle may have an increased risk of miscarriage compared to that of women exposed to low concentrations 8 . In this context, few studies have attempted to explain how PM exposure can trigger female infertility and increase the rate of pregnancy loss 9 , 10 . Furthermore, the precise mechanisms underlying PM exposure-related female infertility are still poorly understood, probably due to the multiplicity of factors affecting female reproductive function and fertility 11 – 13 .…”

Environmental Factors Involved in Maternal Morbidity and Mortality

“…13 Carbon monoxide 14 and PM 2.5 15 are associated with decreased conception rates. Decreased live birth rates are associated with NO 2 , 12,15,16 SO 2 , 17 ozone, 15 and PM 2.5 . 13 An ecologic association between air pollutant peaks and monthly in vitro fertilization pregnancy failure rates has been observed.…”

“…45 Air pollution has been directly associated with reduced fertility. 6 Specifically, NO 2 , 7 PM 2.5 , 7 and metals 12,[24][25][26][27] have been associated with reduced conception rates, infertility, or increased pregnancy loss. Exposure to NO 2 and ozone, particularly around ovulation, may reduce conception.…”