BACKGROUND Pregnancy complications, such as gestational diabetes mellitus (GDM) and hypertensive disorders of pregnancy (HDP), have a great impact on public health. Exposure to ambient air pollution during pregnancy may cause pregnancy complications. The aim of our study is to explore the risk of trimester-specific maternal exposure to air pollutants on complications of pregnancy. METHODS PubMed, EMBASE, Web of Science, and Cochrane were systematically searched for cohort studies published before October 27, 2019 which reported the association between ambient air pollutants (PM2.5, PM10, CO, NO, NO2, NOx, O3, and SO2) and pregnancy complications (GDM, HDP, preeclampsia, and gestational hypertension) during different exposure windows. A meta-analysis was applied to combine relative risks (RRs) and their confidence intervals (CIs) from eligible studies. Quality assessment was conducted and Egger test was used to evaluate the publication bias. All statistical analyses were performed by STATA software (Version 15, StataCorp, College Station, Texas, USA). RESULTS This meta-analysis consisted of 33 cohort studies conducted on 22,253,277 pregnant women. Meta-analyses showed during the first trimester, there were significant associations of PM10 with gestational hypertension (RR = 1.07, 95% CI: 1.02-1.12 per 10 μg/m3, I2 = 0.0%), of SO2 with GDM (RR = 1.04, 95% CI: 1.00-1.08 per 1 ppb increment, I2 = 54.1%), of PM2.5 with preeclampsia (RR = 0.97, 95% CI: 0.95-1.00 per 5 μg/m3, I2 = 4.1%). During the entire pregnancy, PM2.5 significantly increased the risk of hypertensive disorders of pregnancy (RR = 1.18, 95% CI: 1.02-1.34 per 5 μg/m3, I2 = 85.1%). Egger test indicated that wide-scale publication bias was unlikely. CONCLUSION Maternal exposure to ambient air pollutants is associated with pregnancy complications especially during the first trimester. Further large multicenter cohort studies considering different constituents of pollutants, levels of disease severity, sensitive populations, and various exposure windows are warranted in the future research.

中文翻译：

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环境空气污染与妊娠并发症之间的关联：队列研究的系统评价和荟萃分析。

背景技术妊娠并发症，如妊娠期糖尿病（GDM）和妊娠期高血压疾病（HDP），对公众健康有很大影响。怀孕期间暴露于环境空气污染可能导致妊娠并发症。我们研究的目的是探讨妊娠期特定孕产妇暴露于空气污染物对妊娠并发症的风险。方) 和不同暴露窗口期间的妊娠并发症（GDM、HDP、先兆子痫和妊娠高血压）。应用荟萃分析来结合符合条件的研究的相对风险 (RR) 及其置信区间 (CI)。进行质量评估，并使用 Egger 检验评估发表偏倚。所有统计分析均由 STATA 软件（第 15 版，StataCorp，College Station，Texas，USA）进行。结果 这项荟萃分析包括对 22,253,277 名孕妇进行的 33 项队列研究。荟萃分析显示，在妊娠早期，PM10 与妊娠期高血压（RR = 1.07，95% CI：1.02-1.12/10 μg/m3，I2 = 0.0%）、SO2 与 GDM 显着相关（RR = 1.04 , 95% CI: 1.00-1.08 每 1 ppb 增量, I2 = 54.1%), PM2.5 与先兆子痫 (RR = 0.97, 95% CI: 0.95-1.00 每 5 μg/m3, I2 = 4.1%)。在整个怀孕期间，PM2. 5 显着增加妊娠期高血压疾病的风险（RR = 1.18，95% CI：1.02-1.34/5 μg/m3，I2 = 85.1%）。Egger 检验表明不太可能出现广泛的发表偏倚。结论 孕妇暴露于环境空气污染物与妊娠并发症有关，尤其是在妊娠早期。在未来的研究中，有必要进行进一步的大型多中心队列研究，考虑污染物的不同成分、疾病严重程度、敏感人群和各种暴露窗口。