Objective:To investigate the relationship between air pollutants and missed abortion in early pregnancy,explore the probable environmental risk factors for embryo development and missed abortion. Methods:We collected the number of the induced abortion and the missed abortion patients in each month during 6 recent years from 15 general hospitals or gynecology and obstetrics hospitals in urban area of Tianjin.We obtained the average levels of main air pollutants(SO_2、TSP、NO_2) from 2001 to 2007 in six national monitoring stations in urban field of Tianjin from Environment Monitoring Centre monthly,and compared the differences of the percentage of missed abortion cases in all the abortion operations of each months between months,seasons and heating and non-heating period.We used SPSS 11.0 statistic software to analyze probable environmental risk factors for missed abortion. Results:Air pollution in Tianjin during heating period was significantly more serious than non-heating period, while the percentage of missed abortion in all abortions was higher.The levels of PM_(10) and TSP correlated with the percentage of missed abortion cases,and environmental PM_(10) might be a risk factor of missed abortion.Pregnant in autumn and winter might cause an adverse effect on embryo development. Conclusion:Air pollution might have an adverse effect on normal embryo development in early pregnancy. Objective: To investigate the relationship between air pollutants and missed abortion in early pregnancy, explore the probable environmental risk factors for embryo development and missed abortion. Methods: We collected the number of the induced abortion and the missed abortion patients in each month during 6 recently years from 15 general hospitals or gynecology and obstetrics hospitals in urban area of ​​Tianjin. We have the average levels of main air pollutants (SO_2, TSP, NO_2) from 2001 to 2007 in six national monitoring stations in urban field of Tianjin from Environment Monitoring Center monthly, and compared the differences of the percentage of missed abortion cases in all the abortion operations of each months between months, seasons and heating and non-heating period.We used SPSS 11.0 statistic software to analyze probable environmental risk factors for missed abortion. : Air pollution in Tianjin during heating period was significantly more serious than non-heating period, w hile the percentage of missed abortion in all abortions was higher. The levels of PM_ (10) and TSP correlated with the percentage of missed abortion cases, and environmental PM_ (10) might be a risk factor of missed abortion. Pregnant in autumn and winter might cause an adverse effect on embryo development. Conclusion: Air pollution might have an adverse effect on normal embryo development in early pregnancy.