Table 1 Characteristics of the studies in the review
author(year) | Exposure period | Pollutant(s) | Exposure assessment | Study design | Statistical method | Adjustment variables | Data source | Period | Total Number | Case number | Location |
|---|---|---|---|---|---|---|---|---|---|---|---|
Gilboa SM et al.(2005) | Weeks 3–8 of pregnancy | PM10、O3、CO、SO2、NO2 | Air pollutants data from the nearest monitoring station | Case-control | Logistic regression models | Alcohol consumption or smoking during pregnancy, gravidity, maternal age, maternal education, maternal illness, maternal race/ethnicity, parity, plurality, prenatal care, season of conception and so on. | The Texas Birth Defects Registry provided data on birth defect diagnoses for 7,381 livebirths and fetal deaths of infants | 1997–2000 | 607500 | 293 | USA |
Hwang BF et al.(2008) | First trimester | PM10、O3、CO、SO2、NOx | The inverse distance weighting method | Case-control | Logistic regression models | Sex of infant, maternal age, plurality, gestational age and season of conception. | The Taiwanese Birth Registry from 2001 through 2003 | 2001–2003 | 721289 | 653 | Taiwan |
Hansen CA et al.(2009) | Weeks 3–8 of pregnancy | PM10、O3、CO、SO2、NO2 | Air pollutants data from the nearest monitoring station | Case-control | Conditional logistic regression | neonate gender | The Queensland Health Perinatal Data Collection Unit | 1997–2004 | 150308 | none | Australia |
Marshall EG et al.(2010) | Weeks 3–8 of pregnancy | PM2.5、PM10、O3、CO、SO2、NO2 | Air pollutants data from the nearest monitoring station | Case-control | Logistic regression models | mother’s age, race, ethnicity, smoking and drinking alcohol during pregnancy, and season of conception | The New Jersey Department of Health and Senior Services (NJDHSS) Special Child Health Services registry. | 1998–2003 | 690000 | 717 | USA |
Zhu Y et al.(2015) | Weeks 3–8 of pregnancy and the 3 months pre-pregnancy | PM2.5、PM10、O3、CO、SO2、Nox | The inverse distance weighting method | Cohort | Logistic regression models | site/region, maternal age, race, marital status, insurance, pregnancy body mass index, nulliparity, smoking and/or alcohol consumption during pregnancy and so on. | The Consortium on Safe Labor included 12 clinical centers | 2002–2008 | 188102 | 159 | USA |
Tanner JP et al. (2015) | Weeks 3–8 of pregnancy | PM2.5、benzene | The inverse distance weighting method | Cohort | Multivariable Poisson regression | Maternal race/ethnicity, Maternal age, Maternal education, Maternal marital status, Parity | The Florida Birth Defects Registry | 2000–2009 | 2123874 | 923 | USA |
Zhou Y et al.(2017) | Weeks 5–10 of pregnancy | PM2.5、O3 | The Bayesian downscaler model | Case-control | Conditional logistic regression | infant sex, maternal race and ethnicity, maternal education, smoking status during pregnancy, mother’s age, and parity. | The National Birth Defects Prevention Network (NBDPN) and the Centers for Disease Control and Prevention (CDC). | 2001–2007 | 4697523 | 7035 | USA |
Zhao J et al.(2018) | First trimester | PM2.5、PM10、O3、CO、SO2 | Air pollutants data from the nearest monitoring station | Cohort | Multivariate logistic regression models | maternal ages, education levels, infant sexes, parities, the season of conception, the air temperature, the humidity, and the air pressure. | The Wuhan Maternal and Child Health Management Information System | 2011–2013 | 108167 | 133 | China |
Wang L et al.(2019) | First trimester | SO2、NO2、PM10 | The ordinary block kriging | Cohort | Poisson generalized additive model | long-time trend, seasonality, temperature and relative humidity | The Xi’an Birth Defects Monitoring System | 2010–2015 | 755551 | 8865 | China |
Jiang W et al. (2021) | First trimester | CO、NO2、SO2、O3、PM2.5、PM10 | Air pollutants data from the nearest monitoring station | Case-control | Multivariate logistic regression models | maternal age、maternal educational level、gravidity, infant sex, plurality, temperature and relative humidity. | The hospital based birth defect monitoring (HBBDM) system of Hunan Province and the electronic medical records (EMR) | 2015–2018 | none | 589 | China |
Liu FH et al.(2021) | First trimester and the 3 months pre-pregnancy | SO2 | The mean concentration of all air monitoring stations in the city | Case-control | Univariate logistic regression | maternal age, education, season of conception and the mean levels of PM10, as well as NO2 during the same period. | 14 city institutions of maternal and child health. | 2010–2015 | 1365000 | 3086 | China |