The Association between Ambient Particulate Matters Pollutant and Spontaneous Abortion of the First Trimester of Pregnancy in Tehran

Air pollution has been one of the threatening factors of human health during the last century. Particulate matters are the major air pollutants in urban areas. The aim of this study was to determine the effect of ambient particulate mattes on spontaneous abortion. This case-control study was conducted between June 2010 to February 2011 on 148 spontaneous abortion (case group) and 148 pregnant women (control group) in Tehran. From 22 regions of Tehran, 10 hospitals were randomly selected and samples were collected by simple random sampling from these hospitals. The mean of particulate matters was obtained from monitoring stations of Tehran Air Quality Control Company (TAQCC). Collected data was analyzed by the SPSS software using independent sample t-test, chi-square test, multiple and linear regression models. Two groups in the study were matched in participant's age, husband's age, age at first childbirth, educational level, family average income, previous type of delivery and the interval between deliveries, any previous abortion experience, body mass index, parity, duration of residence in Tehran and the amount of time spent at work and outside of home (P>0.05). On analyzing the collected data, it was revealed that the mean of ambient PM10 concentration in case group (94.4±39.22 micro gr/m3) was significantly higher than the control group (83.54±22.55 micro gr/m3) in T-test (P<0.001) and also the rate of abortion was higher in these areas (OR: 1.01, CI95%: 1.003-1.018). For assessing the relationship between gestational age and ambient PM10 concentration, linear regression method was used. Results indicated that there was a negative correlation between these variables. Findings of this study showed that there was a significant relationship between occurrence of spontaneous abortion and the ambient PM10 concentration.