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

Abstract

Background Animal and epidemiologic studies indicate that air pollution may adversely affect fertility. Epidemiologic studies have been restricted largely to couples undergoing fertility treatment or have retrospectively ascertained time‐to‐pregnancy among pregnant women. Objectives We examined the association between residential ambient air pollution and fecundability, the per‐cycle probability of conception, in a large preconception cohort of Danish pregnancy planners. Methods During 2007–2018, we used the Internet to recruit and follow women who were trying to conceive without the use of fertility treatment. Participants completed an online baseline questionnaire eliciting socio‐demographic characteristics, lifestyle factors, and medical and reproductive histories and follow‐up questionnaires every 8 weeks to ascertain pregnancy status. We determined concentrations of ambient nitrogen oxides (NOx), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), particulate matter <2.5 µm (PM2.5) and <10 µm (PM10), and sulphur dioxide (SO2) at each participant's residential address. We calculated average exposure during the year before baseline, during each menstrual cycle over follow‐up and during the entire pregnancy attempt time. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders and co‐pollutants. The analysis was restricted to the 10,183 participants who were trying to conceive for <12 cycles at study entry whose addresses could be geocoded. Results During 12 months of follow‐up, 73% of participants conceived. Higher concentrations of PM2.5 and PM10 were associated with small reductions in fecundability. For example, the FRs for a one interquartile range (IQR) increase in PM2.5 (IQR = 3.2 µg/m3) and PM10 (IQR = 5.3 µg/m3) during each menstrual cycle were 0.93 (95% CI: 0.87, 0.99) and 0.91 (95% CI: 0.84, 0.99), respectively. Other air pollutants were not appreciably associated with fecundability. Conclusions In this preconception cohort study of Danish women, residential exposures to PM2.5 and PM10 were associated with reduced fecundability.

Association Between Neighborhood Disadvantage and Fertility Among Pregnancy Planners in the US

“… 39 Less affluent areas often have higher concentrations of air pollution, 40 which has been associated with adverse fertility outcomes. 41 , 42 , 43 , 44 , 45 , 46 , 47 There also may be fewer amenities such as green spaces to provide capacity restoration for residents, such as reducing stress. 26 , 48 Conversely, urban renewal programs show positive health benefits for local populations, 29 although the effects are mixed when gentrification is taken into account.…”

“…For example, higher neighborhood unemployment has been associated with decreased population-level fertility rates . Less affluent areas often have higher concentrations of air pollution, which has been associated with adverse fertility outcomes . There also may be fewer amenities such as green spaces to provide capacity restoration for residents, such as reducing stress .…”

Air pollution exposure and pregnancy outcomes among women with polycystic ovary syndrome

“…Recently, the relationship between air pollution and reproductive outcomes has become a research focus (6)(7)(8)(9). The exposure to air pollution has been reported to be related to the reduced fecundability and fertility rates or increased risk of infertility (10,11). Ambient particulate matter in the air has been identified to adversely affect the sperm motility and induce the incidence of asthenozoospermia (12).…”

Impacts of climate change on reproductive, perinatal and paediatric health

“…Animal and epidemiological evidence demonstrates that air pollution may influence fertility. Wesselink and colleagues 8 add to this literature using data from a large preconception cohort of Danish couples trying to conceive during 2007–2018. They found that increasing residential ambient concentrations of particulate matter <2.5 µm (PM 2.5 ) and <10 µm (PM 10 ) were associated with reduced fecundability, the per cycle probability of conception.…”