低浓度空气污染与妊娠结局

立陶宛学者最近研究了空气污染与低出生体重和早产的关系。调查了１９９８年Kaunas市出生的３９９８名新生儿生出情况和他们的母亲孕期暴露于空气污染的情况。研究发现在控制混杂因素后，低出生体重调整的OR值随空气甲醛浓度的上升而上升；孕妇暴露于NO２的浓度每增加１０mg／m３其早产的危险就增加２５％（调整的OR＝１．２５，９５％CI：１．０７～１．４６）。妊娠前３个月孕妇暴露于空气污染物的情况对妊娠结局最有影响，而其他妊娠阶段暴露于空气污染物（如NO２和甲醛）与妊娠结局的低出生体重和早产关系不显著。说明新生儿低出生…     

1747例空气污染与妊娠不良结局之间关系的调查研究

目的：定量分析和评价武汉市大气污染对新生儿早产、低出生体重及出生缺陷等不良妊娠结局的影响。方法：收集武汉市硚口区妇幼保健院2011年3月—2013年6月分娩个案资料,对妊娠结局的相关危险因素及不同妊娠大气中PM10和SO2浓度对妊娠结局的影响进行分析。结论：武汉市空气污染已对妊娠结局造成一定影响,应采取严格的空气污染控制措施,降低不良妊娠结局发生率。     

大气污染与不良妊娠结局关系的研究进展

流行病学研究发现大气污染对人群健康已造成一定影响［1］。但以往学者多关注大气污染对成人死亡率和呼吸道疾病发病率的影响,而与不良妊娠结局关系的研究近期才得以重视。不良妊娠结局指正常妊娠以外所有的病理妊娠及分娩期并发症,包括早产、胎膜早破、自然流产、低出生体重、出生缺陷和新生儿窒息等孕产妇及围产儿的不良结局。本文将对大气主要污染物大气颗粒物（PM）、氮氧化物（NOX）、二氧化硫（SO2）、一氧化碳（CO）和臭氧（O3）与不良妊娠结局的低出生体重、早产、出生缺陷、流产、死产和婴儿期死亡之间关系进行综述。     

妊娠期烹调油烟污染物暴露与低出生体重

近年来,流行病学研究表明妊娠期暴露于空气污染物会导致不良妊娠结局。烹调油烟污染是室内空气污染的主要来源之一,油烟污染物可通过母体影响胎儿的生长发育,最终导致胎儿低出生体重,生长发育受限以及其他不良妊娠结局。本文通过对烹调油烟成分构成及其危害、孕期油烟污染物暴露对低出生体重影响及其生物学机制作简要综述。     

妊娠期空气颗粒物暴露与早产

越来越多的研究证据表明,孕妇妊娠期颗粒物暴露可通过母体影响胎儿的发育,导致早产、低出生体重、胎儿生长受限和潜在的不良心血管和呼吸道结局。但研究结果并不一致,且生物学机制尚不明确。本文通过对近年来国内外主要几种颗粒物人体暴露来源和其对早产影响及生物学机制作一简要综述,为控制空气污染和减少早产等不良妊娠结局的发生以及进一步探讨其可能的生物学机制提供基础依据。     

妊娠妇女空气污染暴露相关生物学标记研究进展

空气污染可以导致呼吸道疾病以及心脑血管疾病。妊娠妇女机体处于一种高代谢状态,对空气污染物比较敏感;胎儿处于生长发育的关键时期,对污染物也更敏感。近年来的研究表明,妊娠妇女暴露于空气污染物与各种不良妊娠结局有关,包括自然流产、胎儿生长受限、早产和低出生体质量等。然而,其潜在机制尚不清楚。目前暴露组学、代谢组学的应用筛选出许多空气污染体内暴露的生物学标记物,如DNA加合物等代谢产物。生物学标记物可以用来反映个体的内暴露水平,相比外暴露的污染物监测更为准确,更能反映机体的暴露水平,从而指导探究空气污染暴露与各种妊娠结局相关的潜在机制。     

PM_(2.5)污染与低出生体重发生风险关联的研究进展

PM_(2.5)指环境空气中直径小于或等于2.5微米的颗粒物,可以通过呼吸道等途径进入人体,并诱发氧化应激和炎症反应。研究显示,空气污染与低出生体重、早产、宫内发育迟缓等不良妊娠结局存在关联。本文主要就大气污染物PM_(2.5)与低出生体重发生风险的关联研究进行综述,以期为今后流行病学研究及发生机制研究提供参考。     

妊娠妇女空气污染暴露相关生物学标记研究进展

空气污染可以导致呼吸道疾病以及心脑血管疾病。妊娠妇女机体处于一种高代谢状态,对空气污染物比较敏感;胎儿处于生长发育的关键时期,对污染物也更敏感。近年来的研究表明,妊娠妇女暴露于空气污染物与各种不良妊娠结局有关,包括自然流产、胎儿生长受限、早产和低出生体质量等。然而,其潜在机制尚不清楚。目前暴露组学、代谢组学的应用筛选出许多空气污染体内暴露的生物学标记物,如DNA加合物等代谢产物。生物学标记物可以用来反映个体的内暴露水平,相比外暴露的污染物监测更为准确,更能反映机体的暴露水平,从而指导探究空气污染暴露与各种妊娠结局相关的潜在机制。     

湖北麻城市2007-2012年不良妊娠结局的流行病学特征

不良妊娠结局包括早产、低出生体重、出生缺陷、、窒息、死胎、死产等,不仅会增加新生儿病死率,还会增加社会负担.随着社会的发展和进步以及医疗保健水平的不断提高,婴幼儿的健康水平得到显著改善.但是早产、低出生体重、出生缺陷等不良妊娠结局并没有得到有效的控制,成为威胁婴幼儿健康和公共卫生的重要危险因素.研究发现,近年来西方发达国家的低出生体重发生率仍居高不下,甚至有上升的趋势[1].在我国低出生体重和早产等不良妊娠结局的发生率也处于较高水平[2,3].研究采用湖北省麻城市妇幼保健院的出生分娩资料,分析麻城市不良妊娠结局流行病学的发生变化情况,从而为预防和减少麻城市不良妊娠结局的发生提供依据.     

环境污染对妊娠结局影响的研究进展

环境污染不仅能直接导致人群死亡率和呼吸循环等疾病的发病率升高,而且能引起不良妊娠结局的发生增多。作者综述了国内外环境污染重金属污染、大气污染、电磁污染、交通污染、持久性有机污染物污染)对妊娠结局的影响与不良妊娠结局(早产、低出生体重、出生缺陷、死产等)的文献,提出了环境污染对不良妊娠结局风险的统计学关联证据,并在生物学机制上做了相关探讨。     

不良妊娠结局的环境因素研究进展

妊娠不良结局的相关因素很多,这些危险因素影响着孕妇的健康,增加不良妊娠结局风险,包括早产、低出生体重、出生缺陷等。导致妊娠不良结局的原因目前主要分为母体、胎儿、环境三方面。研究环境因素与不良妊娠结局的关系,减少孕妇高危环境暴露,提前采取干预措施,可避免不良妊娠结局的发生。该文就不良妊娠结局的环境因素研究进展进行综述。     

Ambient air pollution and pregnancy outcomes: a review of the literature

Over the last decade or so, a large number of studies have investigated the possible adverse effects of ambient air pollution on birth outcomes. We reviewed these studies, which were identified by a systematic search of the main scientific databases. Virtually all reviewed studies were population based, with information on exposure to air pollution derived from routine monitoring sources. Overall, there is evidence implicating air pollution in adverse effects on different birth outcomes, but the strength of the evidence differs between outcomes. The evidence is sufficient to infer a causal relationship between particulate air pollution and respiratory deaths in the postneonatal period. For air pollution and birth weight the evidence suggests causality, but further studies are needed to confirm an effect and its size and to clarify the most vulnerable period of pregnancy and the role of different pollutants. For preterm births and intrauterine growth retardation (IUGR) the evidence as yet is insufficient to infer causality, but the available evidence justifies further studies. Molecular epidemiologic studies suggest possible biologic mechanisms for the effect on birth weight, premature birth, and IUGR and support the view that the relation between pollution and these birth outcomes is genuine. For birth defects, the evidence base so far is insufficient to draw conclusions. In terms of exposure to specific pollutants, particulates seem the most important for infant deaths, and the effect on IUGR seems linked to polycyclic aromatic hydrocarbons, but the existing evidence does not allow precise identification of the different pollutants or the timing of exposure that can result in adverse pregnancy outcomes.     

Iron status during pregnancy: setting the stage for mother and infant

Supplementation with iron is generally recommended during pregnancy to meet the iron needs of both mother and fetus. When detected early in pregnancy, iron deficiency anemia (IDA) is associated with a > 2-fold increase in the risk of preterm delivery. Maternal anemia when diagnosed before midpregnancy is also associated with an increased risk of preterm birth. Results of recent randomized clinical trials in the United States and in Nepal that involved early supplementation with iron showed some reduction in risk of low birth weight or preterm low birth weight, but not preterm delivery. During the 3rd trimester, maternal anemia usually is not associated with increased risk of adverse pregnancy outcomes and may be an indicator of an expanded maternal plasma volume. High levels of hemoglobin, hematocrit, and ferritin are associated with an increased risk of fetal growth restriction, preterm delivery, and preeclampsia. While iron supplementation increases maternal iron status and stores, factors that underlie adverse pregnancy outcome are considered to result in this association, not iron supplements. On the other hand, iron supplements and increased iron stores have recently been linked to maternal complications (eg, gestational diabetes) and increased oxidative stress during pregnancy. Consequently, while iron supplementation may improve pregnancy outcome when the mother is iron deficient it is also possible that prophylactic supplementation may increase risk when the mother does not have iron deficiency or IDA. Anemia and IDA are not synonymous, even among low-income minority women in their reproductive years.     

Evidence for increased risks of preterm delivery in a population residing near a freeway in Taiwan

Traffic emissions are a major source of air pollution in urban areas. The results of recent studies have suggested that air pollution may be related to adverse pregnancy outcomes such as low birth weight and preterm delivery. The authors investigated the association between traffic-related air pollution and preterm deliveries. The study group included all first-parity singleton live births that occurred during 1992-1997 to women who lived in a zone along the Zhong-Shan Freeway in Taiwan (N = 6,251). The zone was defined as areas 1,500-m wide on either side of the freeway; it was located in the San-Ming, Nan-Tzu, Chienchen, and Linya wards-all of which are residential areas in East Kaohsiung. The prevalence of deliveries of preterm birth infants was significantly higher among mothers who lived within 500 m of the freeway than among mothers who resided 500-1,500 m from the freeway. In their analysis, the authors controlled for several confounders (e.g., maternal age, season, marital status, maternal education, infant gender). The adjusted odds ratio was 1.30 (95% confidence interval = 1.03, 1.65) for delivery of preterm infants born to mothers who lived within 500 m of the freeway. Such data provide additional support for the hypothesis that air pollution can affect the outcome of pregnancy.     

Effects of psychosocial characteristics of work on pregnancy outcomes: a critical review

Birth outcomes may influence subsequent susceptibility to chronic diseases. With the increased number of women who continue to work during pregnancy, occupational stress has been hypothesized to be a potential contributor to adverse reproductive health outcomes. The Job Demand and Control model has been primarily used in investigating associations between work-related stress and outcomes such as preterm delivery, low birth weight, and spontaneous abortion. A literature review of occupational factors that have been associated with adverse reproductive outcomes was conducted. In studies assessing preterm delivery and low birth weight, some evidence has suggested a modest association with work-related stress but has not been conclusive. In the literature on psychosocial characteristics of work and spontaneous abortion, job strain alone was often not associated with adverse outcomes. However the presence of other risk factors resulted in a synergistic effect which strengthened the odds of an adverse outcome. Future studies should use a prospective design with a large study sample, in which work-related stress exposure data are collected before or in the early stages of the pregnancy. In addition, future research should measure psychosocial characteristics of work both objectively and subjectively.     

The Impact of Prior Poor Birth Outcomes on Smoking Behavior on Subsequent Pregnancies: Analysis of the National PRAMS Data

Objectives The link between cigarette smoking and poor birth outcomes has been well established. However, there is paucity of research investigating the effect of previous history of poor birth outcomes on smoking behavior during subsequent pregnancies. The present study seeks to determine whether a previous preterm or low birth weight delivery impacts maternal smoking during the subsequent pregnancy. Methods Data from the National Pregnancy Risk Assessment Monitoring System (PRAMS) was analyzed. Multiparous women who currently had singleton birth were included in the analysis (N = 137,297). Previous poor birth outcome and smoking were defined based on the PRAMS question that asked women whether their immediate previous baby was born preterm or low birth weight and if they smoked during the index pregnancy. Results Approximately 16.3 % of the women who reported previous poor birth outcome also reported smoking during the subsequent pregnancy. Multiple logistic regression analysis revealed that women who had previous poor birth outcome had 22 % higher odds of smoking during the subsequent pregnancy. Similarly, the odds of smoking during pregnancy were 30 and 13 % higher among women who had previous low birth weight and preterm birth, respectively. Conclusions Women who experienced previous preterm or low birth weight baby had higher prevalence of smoking during the subsequent pregnancy. The occurrence of a preterm/low birth weight may present a critical intervention point for providers to educate women on the risks of repeated poor birth outcomes and provide intervention programs to address high-risk behaviors.     

Individual exposure to nitrogen dioxide and adverse pregnancy outcomes in Kaunas study

Several epidemiological studies have found some evidence suggesting that exposure to air pollutants during pregnancy increases the risk of adverse birth outcomes. In this cohort study, we assessed individual maternal exposure to nitrogen dioxide (NO₂) during pregnancy and examined the association between the exposure and pregnancy outcomes, such as low birth weight (LBW), term low birth weight (TLBW), small for gestational age (SGA) and preterm birth (PB). 3292 women living in Kaunas city, Lithuania, data and their singleton newborns were included in the study. Exposure to NO₂ was assigned to each individual subject during pregnancy based on residential address using an AIRVIRO dispersion model and geographic information system (GIS). The results of the logistic regression analysis showed that LBW risk increased statistically significantly with increasing exposure to NO₂. Increased maternal exposure to NO₂ tended to increase the risk for TLBW, SGA and PB.     

The Impact of Gestational Weight Gain on the Risks of Adverse Maternal and Infant Outcomes among Normal BMI Women with High Triglyceride Levels during Early Pregnancy

A high maternal triglyceride (mTG) level during early pregnancy is linked to adverse pregnancy outcomes, but the use of specific interventions has been met with limited success. A retrospective cohort study was designed to investigate the impact of gestational weight gain (GWG) on the relationship between high levels of mTG and adverse pregnancy outcomes in normal early pregnancy body mass index (BMI) women. The patients included 39,665 women with normal BMI who had a singleton pregnancy and underwent serum lipids screening during early pregnancy. The main outcomes were adverse pregnancy outcomes, including gestational hypertension, preeclampsia, gestational diabetes, cesarean delivery, preterm birth, and large or small size for gestational age (LGA or SGA) at birth. As a result, the high mTG (≥2.05mM) group had increased risks for gestational hypertension ((Adjusted odds ratio (AOR), 1.80; 95% CI, 1.46 to 2.24)), preeclampsia (1.70; 1.38 to 2.11), gestational diabetes (2.50; 2.26 to 2.76), cesarean delivery (1.22; 1.13 to 1.32), preterm birth (1.42, 1.21 to 1.66), and LGA (1.49, 1.33 to 1.68) compared to the low mTG group, after adjustment for potential confounding factors. Additionally, the risks of any adverse outcome were higher in each GWG subgroup among women with high mTG than those in the low mTG group. High mTG augmented risks of gestational hypertension, preeclampsia, preterm birth, and LGA among women with 50th or greater percentile of GWG. Interestingly, among women who gained less than the 50th percentile of GWG subgroups, there was no relationship between high mTG level and risks for those pregnancy outcomes when compared to low mTG women. Therefore, weight control and staying below 50th centile of the suggested GWG according to gestational age can diminish the increased risks of adverse pregnancy outcomes caused by high mTG during early pregnancy.     

Evidence for Increased Risks of Preterm Delivery in a Population Residing near a Freeway in Taiwan

Traffic emissions are a major source of air pollution in urban areas. The results of recent studies have suggested that air pollution may be related to adverse pregnancy outcomes such as low birth weight and preterm delivery. The authors investigated the association between traffic-related air pollution and preterm deliveries. The study group included all first-parity singleton live births that occurred during 1992-1997 to women who lived in a zone along the Zhong-Shan Freeway in Taiwan (N = 6,251). The zone was defined as areas 1,500-m wide on either side of the freeway; it was located in the San-Ming, Nan-Tzu, Chienchen, and Linya wards—all of which are residential areas in East Kaohsiung. The prevalence of deliveries of preterm birth infants was significantly higher among mothers who lived within 500 m of the freeway than among mothers who resided 500-1,500 m from the freeway. In their analysis, the authors controlled for several confounders (e.g., maternal age, season, marital status, maternal education, infant gender). The adjusted odds ratio was 1.30 (95% confidence interval = 1.03, 1.65) for delivery of preterm infants born to mothers who lived within 500 m of the freeway. Such data provide additional support for the hypothesis that air pollution can affect the outcome of pregnancy.