David Warburton, M.D., D.Sc.
Children’s Hospital of Los Angeles
NIEHS Grant D43ES022862
According to research funded by the NIEHS, pollution from the coal-burning stoves used in Ulaanbaatar, Mongolia for winter heating is strongly associated with miscarriages. Ulaanbaatar is the coldest capital city in the world, and one of the most air polluted.
To examine the association between miscarriages and seasonal variation of air pollutants, the investigators used measurements from Mongolian Government Air Quality Monitoring stations and medical records of 1,219 women admitted to the hospital because of miscarriages. The overall rate of miscarriages reported in Ulaanbaatar was similar to that of Western countries, but miscarriages per calendar month increased from 23 per 1,000 live births in May 2011 to 73 per 1,000 live births in December 2011. Monthly average ambient levels of air pollutants increased in relation to hours of darkness and the coldest temperatures, when the coal heating stoves are used most. Regression analysis of ambient pollutants against fetal death revealed dose–response correlations for sulfide dioxide r > 0.9 (p < 0.001), nitrogen dioxide (r > 0.8), carbon monoxide (r > 0.9), PM 10 (r > 0.9) and PM 2.5 (r > 0.8), (p < 0.001), indicating a strong correlation between air pollution and decreased fetal wellbeing.
Although major policy changes are helping to curb air pollution in Mongolia, the researchers speculate that up to a five-fold further reduction in air pollutants in winter would be needed to reduce fetal death rates to levels experienced during the summer in Ulaanbaatar.
Citation: Enkhmaa D, Warburton N, Javzandulam B, Uyanga J, Khishigsuren Y, Lodoysamba S, Enkhtur S, Warburton D. 2014. Seasonal ambient air pollution correlates strongly with spontaneous abortion in Mongolia. BMC Pregnancy Childbirth 14(1):146.