Abstract: Objective To investigate effects of household chemical use during first trimester of pregnancy on adverse birth outcomes,including preterm birth(PB),low birth weight(LBW),and small for gestational age(SGA).Methods A total of 10 269 women of childbearing age who gave birth to single and live babies were recruited from October 2008 to October 2010 in 3 maternal and child health centers in Hefei,Wuhu,and Maanshan city.Chi-square test and binary logistic regression were used to analyze the association between household chemical use and adverse birth outcomes.Results Among the women,whitening cream was most frequently used during the first trimester,while the other household chemicals were rarely used.The incidence of PB,LBW,and SGA were 3.4%(343/10 120),1.8%(183/10 186),and 3.2%(324/10 091),respectively.The adjusted relative risks of PB,LBW,and SGA related to household chemical use were 0.73(95% confidence interval95%CI:0.58-0.91),1.11(95%CI:0.83-1.49),and 1.07(95%CI:0.85-1.33),respectively.Conclusion Overall,the results of the study did not suggest an association between household chemical use of pregnant women during the first trimester and adverse birth outcomes.