Abstract: OBJECTIVE To analyze the association of urogenital Chlamydia trachomatis (CT) infection in the genitourinary tract of pregnant women with HLA-DQ gene polymorphism and its impact on maternal and infant outcomes. METHODS Totally 80 pregnant women with urogenital CT infection who received prenatal examination and gave birth in department of obstetrics of No. 3201 Hospital between Aug. 2017 and Aug. 2021 were selected as infection group, and 50 pregnant women without infection during the same period were selected as the control group. The gene polymorphisms of HLA-DQA1 and HLA-DQB1 were detected and the maternal and infant outcomes were analyzed. The general data, allele distribution of HLA-DQA1 and HLA-DQB1 and the occurrence of adverse maternal and infant outcomes were compared between the two groups of pregnant women. Logistic regression analysis was used to analyze the relationship between CT infection, gene polymorphisms of HLA-DQA1 and HLA-DQB1, and adverse maternal and infant outcomes. RESULTS The frequencies of HLA-DQA1*0102 allele and HLA-DQB1*0602 allele in the infection group were higher than those in the control group, while the frequency of HLA-DQA1*0501 allele was lower than that in the control group (P<0.05). The overall incidence of maternal miscarriage, premature delivery, premature rupture of membranes, intrauterine infection, puerperal infection and postpartum hemorrhage of puerperae and the incidence of neonatal asphyxia, neonatal pneumonia, neonatal pathological jaundice and conjunctivitis were higher in the infection group than those in the control group (P<0.05). Logistic regression analysis showed that genital CT infection of pregnant women and alleles of HLA-DQA1*0102, HLA-DQA1*0501 and HLA-DQB1*0602 were the influencing factors for adverse maternal and infant outcomes (P<0.05). CONCLUSION Urogenital CT infection of pregnant women and gene polymorphisms of HLA-DQA1 and HLA-DQB1 were the influencing factors for adverse maternal and infant outcomes.