Air Pollution and Stillbirth Risk: Exposure to Airborne Particulate Matter during Pregnancy Is Associated with Fetal Death

Abstract

ObjectiveTo test the hypothesis that exposure to fine particulate air pollution (PM2.5) is associated with stillbirth.Study DesignGeo-spatial population-based cohort study using Ohio birth records (2006-2010) and local measures of PM2.5, recorded by the EPA (2005-2010) via 57 monitoring stations across Ohio. Geographic coordinates of the mother’s residence for each birth were linked to the nearest PM2.5 monitoring station and monthly exposure averages calculated. The association between stillbirth and increased PM2.5 levels was estimated, with adjustment for maternal age, race, education level, quantity of prenatal care, smoking, and season of conception.ResultsThere were 349,188 live births and 1,848 stillbirths of non-anomalous singletons (20-42 weeks) with residence ≤10 km of a monitor station in Ohio during the study period. The mean PM2.5 level in Ohio was 13.3 μg/m3 [±1.8 SD, IQR(Q1: 12.1, Q3: 14.4, IQR: 2.3)], higher than the current EPA standard of 12 μg/m3. High average PM2.5 exposure through pregnancy was not associated with a significant increase in stillbirth risk, adjOR 1.21(95% CI 0.96,1.53), nor was it increased with high exposure in the 1st or 2nd trimester. However, exposure to high levels of PM2.5 in the third trimester of pregnancy was associated with 42% increased stillbirth risk, adjOR 1.42(1.06,1.91).ConclusionsExposure to high levels of fine particulate air pollution in the third trimester of pregnancy is associated with increased stillbirth risk. Although the risk increase associated with high PM2.5 levels is modest, the potential impact on overall stillbirth rates could be robust as all pregnant women are potentially at risk.

Prenatal ambient air pollution exposure and the risk of stillbirth: systematic review and meta-analysis of the empirical evidence

“…Regarding the studies conducted by Faiz et al 21 23 and DeFranco et al ,27 mothers had to live within a 10 km radius of the closest monitoring station; and Green et al 28 used 20 km radius for PM 2.5 , O 3 , SO 2 and 5 km radius for CO and NO 2 to be included in the studies. Whereas Hwang et al 24 applied a 25 km radius.…”

“…Six studies21 23 24 27 28 32 used a stillbirth cut-off point of >20 weeks of gestation, with three studies22 25 30 using a cut-off of >28 weeks of gestation. Landgren33 and Sakai31 did not provide a case definition in their reports.…”

The First 5-Year-Long Survey on Intrauterine Unexplained Sudden Deaths from the Northeast Italy

“…From the analysis of the risk factors reported in the filled forms for the mothers, exogenous risk factors, affecting the intrauterine environment, are relevant, such as maternal smoking, maternal alcoholism, abuse of drugs, and likely atmospheric pollution [31][32][33]. In particular, exposure to tobacco smoke in utero is the most important preventable risk factor.…”

“…The smoking, in fact, causes vasoconstriction and reduces the fetal oxygenation and blood flow [34][35][36][37]. In addition, air pollution, which features high rates of both gases (carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide) and particulate matter (above all PM 10 , with a median diameter of <10 µm), could have an important influence in determining SIUDS [32]. We have already postulated that pollutants, cigarette smoke included, can cross the placenta during pregnancy through the maternal blood, and lead to a hypoxic status responsible for structural and/or functional impairments of the central nervous system [38,39].…”

Analysis of risk factors of stillbirth: a hospital based study in a tertiary care centre

“…[3][4][5][6] Exposure to high levels of fine particulate air pollution in the third trimester of pregnancy is reported to be associated with increased stillbirth risk. 7 However pregnancy complication or feto-placental pathology are the major cause of fetal death.The pregnancy complication commonly associated with IUFD as reported in literature are preeclampsia, antpartum haemorrhage (APH), oligohydramnios, intrauterine growth restriction (IUGR). 6,8,9 Helgadottier LB found 68% of the cases the major cause of fetal death was placental pathology(IUFD8).…”