Safe in the womb? Effects of air pollution to the unborn child and neonates

Prenatal exposure to multiple air pollutants and risks of preterm birth and low birth weight in twins: A comparison between natural conception and medically assisted reproduction

Exposure to air pollution has been linked to higher risks of adverse pregnancy outcomes. However, evidence from twin pregnancies is limited, and differences between natural conception (NC) and medically assisted reproduction (MAR) remain unexplored. This study enrolled 935 twin pairs in Wuxi, China, from 2017 to 2022. A high spatiotemporal resolution prediction model was used to assess prenatal exposure to air pollutants, including PM2.5, PM10, SO2, NO2, CO, and O3. Associations of prenatal air pollution exposure with preterm birth (PTB), low birth weight (LBW), and low birth weight preterm birth (LBWPT) were analyzed using generalized linear models. The prevalence of PTB, LBW, and LBWPT among the twin pairs was 68.0 %, 72.4 %, and 57.5 %, respectively. Prenatal exposures to PM2.5, PM10, SO2, and CO were significantly associated with increased risks of PTB, LBW, and LBWPT. Subgroup analyses revealed increased risks in the MAR group (SO2) for PTB and LBWPT, the NC group (CO) for LBW, and twins born in winter/spring (PM2.5, PM10, SO2) for PTB and LBWPT. Our findings underscore the importance of tailoring preventive measures to MAR-conceived twins, NC twins, and those born in winter/spring to better protect against the adverse effects of prenatal air pollution exposure.

Impact of air pollution and climate change on maternal, fetal and postnatal health

OBJECTIVE

Besides socioeconomic factors, environmental pollution, and climate change are contemporary threats to health. In this review, the authors present results from a recent comprehensive synthesis of existing research on the effects of air pollution and climate change on gestation, fetal development, and postnatal health.

DATA SOURCES

Findings from systematic reviews conducted over the past five years and available in PubMed were used.

SUMMARY OF FINDINGS

A vast and robust evidence exists on the association between air pollution exposures and negative outcomes. Gestational diabetes, hypertensive disorders of pregnancy, preeclampsia, spontaneous abortion, and maternal postpartum depression are reported. Fetal development and postnatal health are also impaired by exposures; low birth weight is a common finding from studies worldwide, but there are increased risks for malformations and impairments in neurodevelopment. While there are fewer studies on factors related to climate change, there is sufficient evidence regarding the direct and indirect effects on maternal health and fetal development. Increased risks for prematurity, low birth, and emergency room visits are associated with higher temperatures. Asthma incidence and infectious respiratory disease risks are also influenced by extreme weather events. It is essential to recognize the profound impact that environmental factors, such as air pollution and climate change can have on maternal health, fetal development, and neonatal health.

CONCLUSION

The data presented underscores the significant risks that environmental pollution poses during gestation, influencing not only maternal health but also the short- and long-term well-being of the child.

Involvement of Maternal and Socioeconomic Risk Factors in the Incidence of Fetal Growth Restriction in a Large Maternity Hospital in Romania

Background: Fetal growth restriction (FGR) refers to a condition in which a fetus does not reach its genetically predetermined growth potential due to various pathological factors of maternal or fetal origin, with potential long-life consequences, such as elevated blood pressure, type 2 diabetes mellitus, obesity, dyslipidemia, atherosclerosis. Aim: The purpose of our research is to delve into the intricate relationship between economic and social factors and the occurrence of FGR. Methods: We analyzed risk factors previously associated with FGR and aimed to compare them between two cohorts of infants with FGR: a historical cohort of infants born from 2010 to 2012 and a contemporary cohort of infants born from 2020 to 2022. Results: The global incidence of FGR in our study was 5.13%, with non-significant differences between the two time periods: 5.03% in the historical cohort and 5.25% in the contemporary cohort. More mothers of FGR infants receive formal education and are employed in the contemporary group and thus have a more stable income. There was a major decrease in the number of preterm infants with FGR, from 23.9% in the historical cohort to 5.9% in the contemporary cohort (p < 0.001). Compared to the historical cohort, we found significant increases in the incidence of pregnancy-induced hypertension, Cesarean sections, and prenatal follow-up in the contemporary cohort (8.3% vs. 3.8%, p < 0.001; 59.2% vs. 49.9%, p < 0.001; 67.7% vs. 49.6%, p < 0.001, respectively) and we also found significant correlations between prenatal care on one side and maternal smoking, urban residence, higher maternal education, and prematurity on the other. Conclusions: Certain socioeconomic factors show definite improvements over the ten-year timespan, which results in an increase in prenatal care and a decrease in the rate of prematurity. However, the incidence of FGR remains constant over the considered period, meaning that other factors, apart from socioeconomic factors, play a substantial role. Recognizing these risk factors is crucial for developing effective public health strategies aimed at reducing the incidence of FGR and improving maternal and child outcomes.

A case-crossover study of air pollution exposure during pregnancy and the risk of stillbirth in Tehran, Iran

The growing fetus is very sensitive to environmental conditions. There is limited and conflicting evidence about the short-term effects of exposure to air pollutants on the pregnancy outcome. In this time-stratified case-crossover study, the effect of several air pollutants (i.e. O3, CO, NO2, SO2, and PM2.5) on the occurrence of stillbirth was evaluated in Tehran (the capital of Iran) between December 2018 and March 2023. Using a quasi-Poisson regression model and distributed lag nonlinear models (DLNM), we estimated the effect of exposure to air pollutants measured as lags (0 to 7 days) and cumulative average days (0-2, 0-6, and 0-14-day lag) before delivery on stillbirth. The association was adjusted for potential confounding factors including meteorological factors. During the study period in Tehran, 5311 stillbirths were reported. In single-pollutant models, during the entire year, SO2 (lag 1 day) and NO2 (lag 2 days) were found to have a direct and significant relationship with stillbirth. In the warm seasons, we found direct and inverse relationships between NO2 (lag 2 days) and PM2.5 (lag 4 days), respectively. In cold seasons, PM 2.5 (lag 1 day) and cumulative lag (0-2 days), SO2 (lag 1 day), and cumulative lag (0-2 and 0-6 days) were found to have direct and significant relationships with stillbirth. In two-pollutant models, SO2 & CO, and SO2 & O3, direct and significant associations were observed between SO2 exposures and stillbirth for the entire year. A similar pattern was observed for PM2.5 in combinations with NO2, and O3 and for NO2 in the two-pollutant model (O3 & NO2). However, in warm seasons, inverse associations were observed between PM2.5 and stillbirth in combinations with O3, NO2, and SO2, while NO2 showed a direct association in combinations with PM2.5, CO, and O3. In the cold seasons, direct and significant associations were observed between SO2 and stillbirth in model combinations with CO, O3, and NO2. This relationship was observed for PM2.5 in combination with CO, and NO2. Also, for CO in the two-pollutant model of CO & NO2. As a result, this study showed evidence of a relationship between short-term exposure to ambient air pollution before birth, especially SO2, NO2, PM2.5, and CO with increased risk of stillbirth.

Short term air pollution exposure during pregnancy and associations with maternal immune markers

BACKGROUND

Air pollution exposure during pregnancy has been associated with numerous adverse pregnancy, birth, and child health outcomes. One proposed mechanism underlying these associations is maternal immune activation and dysregulation. We examined associations between PM2.5 and NO2 exposure during pregnancy and immune markers within immune function groups (TH1, TH2, TH17, Innate/Early Activation, Regulatory, Homeostatic, and Proinflammatory), and examined whether those associations changed across pregnancy.

METHODS

In a pregnancy cohort study (n = 290) in Rochester, New York, we measured immune markers (using Luminex) in maternal plasma up to 3 times during pregnancy. We estimated ambient PM2.5 and NO2 concentrations at participants' home addresses using a spatial-temporal model. Using mixed effects models, we estimated changes in immune marker concentrations associated with interquartile range increases in PM2.5 (2.88 μg/m3) and NO2 (7.82 ppb) 0-6 days before blood collection, and assessed whether associations were different in early, mid, and late pregnancy.

RESULTS

Increased NO2 concentrations were associated with higher maternal immune markers, with associations observed across TH1, TH2, TH17, Regulatory, and Homeostatic groups of immune markers. Furthermore, the largest increases in immune markers associated with each 7.82 ppb increase in NO2 concentration were in late pregnancy (e.g., IL-23 = 0.26 pg/ml, 95% CI = 0.07, 0.46) compared to early pregnancy (e.g., IL-23 = 0.08 pg/ml, 95% CI = -0.11, 0.26).

CONCLUSIONS

Results were suggestive of NO2-related immune activation. Increases in effect sizes from early to mid to late pregnancy may be due to changes in immune function over the course of pregnancy. These findings provide a basis for immune activation as a mechanism for previously observed associations between air pollution exposure during pregnancy and reduced birthweight, fetal growth restriction, and pregnancy complications.

Maternal NO2 exposure and fetal growth restriction: Hypoxia transmission and lncRNAs-proinflammation-mediated abnormal hematopoiesis

Epidemiological studies show a strong correlation between air pollution and fetal growth restriction (FGR), but existing results are controversial due to inherent limitations, such as causality of specific pollutants, developmental origin, and maternal-fetal transmission. To address this controversy, we first conducted a retrospective analysis of 28,796 newborns and revealed that maternal nitrogen dioxide (NO2) exposure during the second trimester was positively associated with FGR, with an adjusted odds ratio of 1.075 (95% confidence interval: 1.020-1.133) per 10 μg/m3 NO2 increase for small for gestational age. Then, by establishing an animal model of prenatal NO2 exposure, we confirmed its adverse effects on embryonic growth and hematopoiesis in the yolk sac and fetal liver, primarily affecting the differentiation of hematopoietic stem and progenitor cells and erythroid maturation. By applying internal exposure analyses coupled with 15N isotope tracing, we found that maternal NO2 inhalation induced acquired methemoglobinemia through its byproducts and placental hypoxia in pregnant mice. Importantly, by combining transcriptional profiling, bioinformatics analysis, and RNA binding protein immunoprecipitation (RIP)/chromatin immunoprecipitation (CHIP), we clarified that placental-fetal hypoxia transmission activated hypoxia-inducible factors, disturbed hematopoiesis through the hypoxia-inducible factor 1β-long noncoding RNAs-CCAAT/enhancer binding protein alpha-proinflammatory signaling pathway, ultimately contributing to FGR progression. These findings provide insights for risk prevention and clinical intervention to promote child well-being in NO2-polluted areas.

Effect of environmental air pollutants on placental function and pregnancy outcomes: a molecular insight

Air pollution has become a major health concern, particularly for vulnerable populations such as the elderly, children, and pregnant women. Studies have reported a strong association between prenatal exposure to air pollutants and adverse pregnancy outcomes, including lower birth weight, reduced fetal growth, and an increased frequency of preterm births. This review summarizes the harmful effects of air pollutants, such as particulate matter, on pregnancy and outlines the mechanistic details associated with these adverse outcomes. Particulate pollutant matter may be able to cross the placenta barrier, and alterations in placental functions are central to the detrimental effects of these pollutants. In addition to associations with preeclampsia and gestational hypertension, air pollutants also induce oxidative stress, inflammation, and epigenetic alteration in the placenta. These pollutants can also affect placental homeostasis and endocrine function, contributing to pregnancy complications and possible transgenerational effects. Prenatal air pollution exposure has been linked to reduced cognitive and motor function in infants and newborns, increasing the predisposition to autism spectrum disorders and other neuropsychiatric disorders. This review also summarizes the use of various animal models to study the harmful effects of air pollution on pregnancy and postnatal outcomes. These findings provide valuable insight into the molecular events associated with the process and can aid in risk mitigation and adopting safety measures. Implementing effective environmental protocols and taking appropriate steps may reduce the global disease burden, particularly for developing nations with poor regulatory compliance and large populations of pregnant women.

The effect of toxic air pollutants on fertility men and women, fetus and birth rate

Human health is affected by various factors such as air pollutants. Exposure to toxic air pollutants is impaired fertility in men and women. The purpose of this review study was investigation of the effect of toxic air pollutants on fertility and birth rate. Databases used to for searched were the PubMed, Web of Science, Springer and Science Direct (Scopus) and Google Scholar. Identify all relevant studies published 1999-2022. In this study, according to databases five hundred articles were retrieved. 33 studies were screened after review and 19 full-text articles entered into the analysis process. Finally, 11 articles were selected in this study. The literature signs a notable health effects from toxic air pollutants and increase risk of infertility in men and women and having a variety of reproductive system cancers such as prostate, bladder, ovary, kidney and uterus. According to the finding toxic air pollutants can increase the risk infertility in men and women, incidence of cancers of reproductive system and decrease the birth rate. Activities that play an important role in reducing the health effects of toxic air pollutants such as infertility in men and women and reducing the population rate of communities are improving the quality of fuel used in the home, car, industries, changing production processes in large industries, installing catalysts to reduce emissions in cars, use more public transportation, plant trees and increase green space per capita, increase public awareness about various effects of toxic air pollutants and protective measures.

Impact of Environmental Quality on Healthcare Expenditures in Developing Countries: A Panel Data Approach

Objective: The deterioration in environmental quality has an economic and social cost. The aim of this study is to analyze the impact of environmental factors on health expenditures in developing countries. Method: To analyze the relationship between environmental quality (air pollution and temperature) and health expenditure in thirty-three developing countries, the study uses system generalized method of moments (GMM) using data from 2000 to 2017. Results: The results suggest a positive effect of both air pollution and temperature on health expenditure. However, the effect is highest for government health expenditure, followed by private and total health expenditure in the studied countries. The results further suggest that the impact of environmental factors is greater in higher-income countries when we divide the studied countries into two groups, i.e., higher- and lower-income countries. Conclusion: Our results are interesting and informative for the policy makers to design such policies to attain better environmental quality and social well-being. The increased healthcare expenditures due to increased air pollution and climate change necessitate for an efficient, reliable, affordable and modern energy policy by emphasizing the use of clean and renewable energy in these countries that ensure better health for the masses. Furthermore, a smart and sustainable environmentally friendly economic growth policy is necessary to ensure better health for the masses.