Objective:To understand the clinical characteristics of pregnant women infected with dengue virus (DENV) in Ruili City, Yunnan Province, so as to provide basis for formulating effective diagnosis and treatment protocol of dengue fever in pregnant women.Methods:A total of 18 pregnant women infected with DENV hospitalized in Ruili People's Hospital in 2017 and 2018 were selected as observation group, and 18 non-pregnant women infected with DENV were selected as control group according to the age range of the observation group, and epidemiological and clinical data of patients in the two groups were retrospectively collected. Epidemiological characteristics, clinical symptoms and laboratory biochemical indexes of the two groups were compared and analyzed.Results:There were no significant differences ( t = - 0.032, 0.495, P > 0.05) in age [(27.9 ± 5.3) vs (27.9 ± 5.1) years old] and hospitalization stay [(6.8 ± 1.6) vs (6.6 ± 2.0) d] between the observation group and control group. One pregnant woman in observation group had early pregnancy abortion. Patients of both groups had fever in 18 cases (100.0%), headache, muscle aches, and chills in 14 cases (77.8%), anorexia in 15 cases (83.3%), and nausea and vomiting in 5 cases (27.8%); fatigue in 14 cases (77.8%) and 16 cases (88.9%), respectively; there was 1 case of rash in observation group (5.6%), and no rash in control group. There were no significant differences in the above mentioned clinical symptoms distribution between the two groups ( P > 0.05). On the first day of admission, the reduction proportions in red blood cells [61.1% (11/18) vs 5.6% (1/18)], hemoglobin [50.0% (9/18) vs 16.7% (3/18)], and hematocrit [61.1% (11/18) vs 16.7% (3/18)] in observation group were significantly higher than those in control group ( P < 0.05); on the fifth day of admission, the reduction proportions in hemoglobin [33.3% (6/18) vs 5.6% (1/18)] and hematocrit [33.3% (6/18) vs 5.6% (1/18)] in observation group were significantly higher than those in control group ( P < 0.05). Conclusions:The red blood cells, hemoglobin and hematocrit of pregnant women infected with DENV are significantly reduced, and there is a risk of miscarriage in early pregnancy. It is suggested that relevant departments should strengthen the training of medical staff to diagnose and treat pregnant women infected with DENV early.