nitrogen-dioxide and Stillbirth

Individual studies on the relations between ambient air pollution and the risk of stillbirth have provided contradictory results. We conducted a systematic review and meta-analysis to summarise the existing evidence.. We conducted a systematic search of three databases: PubMed, Scopus and Web of Science, from their time of inception to mid-April, 2015. Original studies of any epidemiological design were included. Data from eligible studies were extracted by two investigators. To calculate the summary effect estimates (EE), the random effects model was used with their corresponding 95% CI.. 13 studies met the inclusion criteria. Although not reaching statistical significance, all the summary effect estimates for the risk of stillbirth were systematically elevated in relation to mean prenatal exposure to NO2 per 10 ppb (EE=1.066, 95% CI 0.965 to 1.178, n=3), CO per 0.4 ppm (EE=1.025, 95% CI 0.985 to 1.066, n=3), SO2 per 3 ppb (EE=1.022, 95% CI 0.984 to 1.062, n=3,), PM2.5 per 4 μg/m(3) (EE=1.021, 95% CI 0.996 to 1.046, n=2) and PM10 per 10 μg/m(3) (EE=1.014, 95% CI 0.948 to 1.085, n=2). The effect estimates for SO2, CO, PM10 and O3 were highest for the third trimester exposure. Two time series studies used a lag term of not more than 6 days preceding stillbirth, and both found increased effect estimates for some pollutants.. The body of evidence suggests that exposure to ambient air pollution increases the risk of stillbirth. Further studies are needed to strengthen the evidence.

Topics: Air Pollutants; Air Pollution; Carbon Monoxide; Environmental Monitoring; Female; Humans; Maternal Exposure; Nitrogen Dioxide; Ozone; Particulate Matter; Pregnancy; Pregnancy Trimester, Third; Risk Factors; Stillbirth; Sulfur Dioxide

Air pollution poses a threat to human health, with pregnant women and their developing fetuses being particularly vulnerable. A high dual burden of ambient and indoor air pollution exposure has been identified in Ethiopia, but studies investigating their effects on adverse birth outcomes are currently lacking. This study explores the association between ambient air pollution (NO

Topics: Air Pollutants; Air Pollution; Air Pollution, Indoor; Ethiopia; Female; Humans; Infant, Newborn; Nitrogen Dioxide; Particulate Matter; Perinatal Death; Pregnancy; Prospective Studies; Stillbirth

Evidence for associations between ambient air pollution and preterm birth and stillbirth is inconsistent. Road traffic produces both air pollutants and noise, but few studies have examined these co-exposures together and none to date with all-cause or cause-specific stillbirths.. To analyse the relationship between long-term exposure to air pollution and noise at address level during pregnancy and risk of preterm birth and stillbirth.. The study population comprised 581,774 live and still births in the Greater London area, 2006-2010. Outcomes were preterm birth (<37 completed weeks gestation), all-cause stillbirth and cause-specific stillbirth. Exposures during pregnancy to particulate matter with diameter <2.5 μm (PM. An interquartile range increase in O. Our findings suggest that exposure to higher levels of O

Topics: Air Pollutants; Air Pollution; Female; Humans; Infant, Newborn; London; Nitrogen Dioxide; Particulate Matter; Pregnancy; Premature Birth; Stillbirth

Associations between ambient air pollution and stillbirth have recently been explored, but most studies have focused on long-term (trimester or gestational averages) rather than short-term (within one week) air pollution exposures.. To evaluate whether short-term exposures to criteria air pollutants are associated with increased risk of stillbirth.. Using air pollution and fetal death certificate data from 1999 to 2009, we assessed associations between acute prenatal air pollution exposure and stillbirth in California. In a time-stratified case-crossover study, we analyzed single day and/or cumulative average days (up to a 6 day lag) of exposure to fine (PM. Stillbirth cases in the primary analyses ranged between 1,203 and 13,018, depending on the pollutant. For an IQR increase in SO. This study provides evidence for associations between prenatal short-term air pollution exposure, specifically SO

Topics: Air Pollutants; Air Pollution; California; Cross-Over Studies; Environmental Exposure; Female; Humans; Nitrogen Dioxide; Ozone; Particulate Matter; Pregnancy; Stillbirth; Sulfur Dioxide

In a racially and ethnically diverse urban area (Harris County, Texas) with historic nonattainment O3 levels, we obtained birth and fetal death records from 2008-2013 and estimated maternal residential O3 concentrations from conception until delivery using inverse-distance interpolation from the local air monitoring network. We examined multipollutant models (with fine particulate matter and nitrogen dioxide) and effect measure modification by race/ethnicity and length of gestation. We found a 9% (95% confidence interval (CI): 1, 18) increased stillbirth risk associated with a 3.6-parts-per-billion increase in O3 exposure. The risk was higher among women with pregnancies of <37 gestational weeks (hazard ratio (HR) = 1.13, 95% CI: 1.04, 1.23) compared with women with pregnancies of longer gestation (HR = 1.05, 95% CI: 0.87, 1.27) and among Hispanic women (HR = 1.14, 95% CI: 1.02, 1.27). We also conducted a case-crossover analysis and detected no associations with short-term exposure. To our knowledge, this study is the first to use time-to-event analyses to examine stillbirth risk associated with time-varying prenatal ozone (O3) exposure over pregnancy. Our findings indicate that maternal O3 exposure over pregnancy is associated with stillbirth risk and that Hispanic women and women with shorter pregnancies might be at particular risk.

Topics: Adult; Air Pollutants; Environmental Exposure; Female; Humans; Maternal Exposure; Nitrogen Dioxide; Ozone; Particulate Matter; Pregnancy; Risk; Stillbirth; Texas; Urban Health; Urban Population

Pregnant women may be vulnerable to changes in ambient temperature and warming climates. Recent evidence suggests that temperature increases are associated with placental abruption, a risk factor for stillbirth.. We investigated the effect of acute exposures to apparent temperature on stillbirths in Harris County, Texas, 2008-2013.. Independent of air pollutant exposures, a 10 °F increase in apparent temperature in the week preceding delivery (lag days 1 to 6) was positively associated with a 45% (adjusted OR = 1.45, 95% confidence interval (CI): 1.18, 1.77) increase in risk for stillbirth. Risks were elevated for stillbirths occurring in June through August, for Hispanic and non-Hispanic Black women, but not for non-Hispanic Whites. We also observed elevated risks associated with temperature increases in the few days preceding delivery among stillbirths caused by placental abruption, with the risk being highest on lag day 1 (OR = 1.93, 95% CI: 1.15, 3.23).. Independent of maternal ambient air pollutant exposure, we found evidence of an association between apparent temperature increases in the week preceding an event and risk of stillbirth. Risks for stillbirth varied by race/ethnicity. Further, in the first study to evaluate the impact of temperature on a specific complication during pregnancy, the risks were higher among mothers with placental abruption.

Topics: Abruptio Placentae; Adult; Air Pollution; Cross-Over Studies; Female; Humans; Nitrogen Dioxide; Particulate Matter; Pregnancy; Risk Factors; Stillbirth; Temperature; Texas; Weather; Young Adult

Recent studies have suggested an association between air pollution and stillbirth. In this California study, we examined the records of 13,999 stillbirths and 3,012,270 livebirths occurring between 1999 and 2009. Using a retrospective cohort design and logistic regression models, we calculated the odds of stillbirth associated with each pollutant exposure by trimester and throughout the entire pregnancy. Covariates considered in the model included infant sex, maternal demographic characteristics, season of last menstrual period, apparent temperature, air basin of mother's residence, and year of conception. In single-pollutant models, we found that a 10-µg/m(3) increase in particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (odds ratio (OR) = 1.06, 95% confidence interval (CI): 0.99, 1.13) and a 10-ppb increase in nitrogen dioxide (OR = 1.08, 95% CI: 1.03, 1.13) during the entire pregnancy were associated with stillbirth. A 10-ppb increase in ozone exposure during the third trimester was also associated with a slightly elevated risk (OR = 1.03, 95% CI: 1.01, 1.05). These ozone and nitrogen dioxide findings were fairly stable after adjustment in 2-pollutant models. However, adjustment for nitrogen dioxide attenuated the full-pregnancy-particulate matter relationship. No significant associations were found for sulfur dioxide or carbon monoxide. These findings support growing evidence of an association between air pollution and adverse birth outcomes.

Topics: Air Pollutants; Air Pollution; California; Carbon Monoxide; Female; Gestational Age; Humans; Maternal Exposure; Nitrogen Dioxide; Ozone; Particulate Matter; Pregnancy; Pregnancy Trimesters; Retrospective Studies; Risk Factors; Sex Factors; Socioeconomic Factors; Stillbirth; Sulfur Dioxide; Temperature

We previously reported an increased risk of stillbirth associated with increases in trimester-specific ambient air pollutant concentrations. Here, we consider whether sudden increase in the mean ambient air pollutant concentration immediately before delivery triggers stillbirth.. We used New Jersey linked fetal death and hospital discharge data and hourly ambient air pollution measurements from particulate matter ≤ 2.5 mm (PM2.5), carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) monitors across New Jersey for the years 1998-2004. For each stillbirth, we assigned the concentration of air pollutants from the closest monitoring site within 10 km of the maternal residence. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of stillbirth associated with interquartile range (IQR) increases in the mean pollutant concentrations on lag day 2 and lag days 2 through 6 before delivery, and whether these associations were modified by maternal risk factors.. The relative odds of stillbirth increased with IQR increases in the mean concentrations of CO (odds ratio [OR] = 1.20, 95% confidence interval [CI] = 1.05-1.37), SO2 (OR = 1.11, 95% CI = 1.02-1.22), NO2 (OR = 1.11, 95% CI = 0.97-1.26), and PM2.5 (OR = 1.07, 95% CI = 0.93-1.22) 2 days before delivery. We found similar associations with increases in pollutants 2 through 6 days before delivery. These associations were not modified by maternal risk factors.. Short-term increases in ambient air pollutant concentrations immediately before delivery may trigger stillbirth.

Topics: Adult; Air Pollutants; Air Pollution; Carbon Monoxide; Female; Humans; New Jersey; Nitrogen Dioxide; Particulate Matter; Pregnancy; Risk Assessment; Risk Factors; Stillbirth; Sulfur Dioxide; Time Factors

The purpose of the present study was to examine the risk of stillbirth associated with ambient air pollution during pregnancy. Using live birth and fetal death data from New Jersey from 1998 to 2004, the authors assigned daily concentrations of air pollution to each birth or fetal death. Generalized estimating equation models were used to estimate the relative odds of stillbirth associated with interquartile range increases in mean air pollutant concentrations in the first, second, and third trimesters and throughout the entire pregnancy. The relative odds of stillbirth were significantly increased with each 10-ppb increase in mean nitrogen dioxide concentration in the first trimester (odds ratio (OR) = 1.16, 95% confidence interval (CI): 1.03, 1.31), each 3-ppb increase in mean sulfur dioxide concentration in the first (OR = 1.13, 95% CI: 1.01, 1.28) and third (OR = 1.26, 95% CI: 1.03, 1.37) trimesters, and each 0.4-ppm increase in mean carbon monoxide concentration in the second (OR = 1.14, 95% CI: 1.01, 1.28) and third (OR = 1.14, 95% CI: 1.06, 1.24) trimesters. Although ambient air pollution during pregnancy appeared to increase the relative odds of stillbirth, further studies are needed to confirm these findings and examine mechanistic explanations.

Topics: Adult; Air Pollutants; Air Pollution; Carbon Monoxide; Cohort Studies; Female; Humans; Maternal Exposure; Middle Aged; Models, Statistical; New Jersey; Nitrogen Dioxide; Odds Ratio; Particulate Matter; Pregnancy; Pregnancy Trimesters; Risk Factors; Stillbirth; Sulfur Dioxide